Immunotherapy Combining Mimotopes Selected by Phage Display Plus Amphotericin B Is Effective for Treatment Against Visceral Leishmaniasis.

The treatment for visceral leishmaniasis (VL) causes toxicity in patients, entails high cost and/or leads to the emergence of resistant strains. No human vaccine exists, and diagnosis presents problems related to the sensitivity or specificity of the tests. Here, we tested two phage clones, B1 and D11, which were shown to be protective against Leishmania infantum infection in a murine model as immunotherapeutics to treat mice infected with this parasite species. The phages were used alone or with amphotericin B (AmpB), while other mice received saline, AmpB, a wild-type phage (WTP) or WTP/AmpB. Results showed that the B1/AmpB and D11/AmpB combinations induced polarised Th1-type cellular and humoral responses, which were primed by high levels of parasite-specific IFN-γ, IL-12, TNF-α, nitrite and IgG2a antibodies, which reflected in significant reductions in the parasite load in distinct organs of the animals when analyses were performed 1 and 30 days after the treatments. Reduced organic toxicity was also found in these animals, as compared with the controls. In conclusion, preliminary data suggest the potential of the B1/AmpB and D11/AmpB combinations as immunotherapeutics against L. infantum infection.

Red-on-yellow queen bio-layer interferometry reveals functional diversity within micrurus venoms and toxin resistance in prey species

Snakes in the family Elapidae largely produce venoms rich in three-fnger toxins (3FTx) that bind to the α1 subunit of nicotinic acetylcholine receptors (nAChRs), impeding ion channel activity. These neurotoxins immobilize the prey by disrupting muscle contraction. Coral snakes of the genus Micrurus are specialist predators who produce many 3FTx, making them an interesting system for examining the coevolution of these toxins and their targets in prey animals. We used a bio-layer interferometry technique to measure the binding interaction between 15 Micrurus venoms and 12 taxon-specifc mimotopes designed to resemble the orthosteric binding region of the muscular nAChR subunit. We found that Micrurus venoms vary greatly in their potency on this assay and that this variation follows phylogenetic patterns rather than previously reported patterns of venom composition. The long-tailed Micrurus tend to have greater binding to nAChR orthosteric sites than their short-tailed relatives and we conclude this is the likely ancestral state. The repeated loss of this activity may be due to the evolution of 3FTx that bind to other regions of the nAChR. We also observed variations in the potency of the venoms depending on the taxon of the target mimotope. Rather than a pattern of prey-specifcity, we found that mimotopes modeled after snake nAChRs are less susceptible to Micrurus venoms and that this resistance is partly due to a characteristic tryptophan→serine mutation within the orthosteric site in all snake mimotopes. This resistance may be part of a Red Queen arms race between coral snakes and their prey.

Red‑on‑yellow queen: bio‑layer interferometry reveals functional diversity within Micrurus venoms and toxin resistance in prey species

Snakes in the family Elapidae largely produce venoms rich in three-fnger toxins (3FTx) that bind to the α1 subunit of nicotinic acetylcholine receptors (nAChRs), impeding ion channel activity. These neurotoxins immobilize the prey by disrupting muscle contraction. Coral snakes of the genus Micrurus are specialist predators who produce many 3FTx, making them an interesting system for examining the coevolution of these toxins and their targets in prey animals. We used a bio-layer interferometry technique to measure the binding interaction between 15 Micrurus venoms and 12 taxon-specifc mimotopes designed to resemble the orthosteric binding region of the muscular nAChR subunit. We found that Micrurus venoms vary greatly in their potency on this assay and that this variation follows phylogenetic patterns rather than previously reported patterns of venom composition. The long-tailed Micrurus tend to have greater binding to nAChR orthosteric sites than their short-tailed relatives and we conclude this is the likely ancestral state. The repeated loss of this activity may be due to the evolution of 3FTx that bind to other regions of the nAChR. We also observed variations in the potency of the venoms depending on the taxon of the target mimotope. Rather than a pattern of prey-specifcity, we found that mimotopes modeled after snake nAChRs are less susceptible to Micrurus venoms and that this resistance is partly due to a characteristic tryptophan→serine mutation within the orthosteric site in all snake mimotopes. This resistance may be part of a Red Queen arms race between coral snakes and their prey.

Mimotope discovery as a tool to design a vaccine against Zika and dengue viruses.

Vaccine development against dengue virus is challenging because of the antibody-dependent enhancement of infection (ADE), which causes severe disease. Consecutive infections by Zika (ZIKV) and/or dengue viruses (DENV), or vaccination can predispose to ADE. Current vaccines and vaccine candidates contain the complete envelope viral protein, with epitopes that can raise antibodies causing ADE. We used the envelope dimer epitope (EDE), which induces neutralizing antibodies that do not elicit ADE, to design a vaccine against both flaviviruses. However, EDE is a discontinuous quaternary epitope that cannot be isolated from the E protein without other epitopes. Utilizing phage display, we selected three peptides that mimic the EDE. Free mimotopes were disordered and did not elicit an immune response. After their display on adeno-associated virus (AAV) capsids (VLP), they recovered their structure and were recognized by an EDE-specific antibody. Characterization by cryo-EM and enzyme-linked immunosorbent assay confirmed the correct display of a mimotope on the surface of the AAV VLP and its recognition by the specific antibody. Immunization with the AAV VLP displaying one of the mimotopes induced antibodies that recognized ZIKV and DENV. This work provides the basis for developing a Zika and dengue virus vaccine candidate that will not induce ADE.

Tumor antigen-unbiased variable epitope library contains mimotopes with antitumor effect in a mouse model of breast cancer.

Breast cancer is one of the leading causes of death that affects the female population worldwide. Despite advances in treatments and a greater understanding of the disease, there are still difficulties in successfully treating patients. Currently, the main challenge in the field of cancer vaccines is antigenic variability which can reduce antigen-specific T- cell response efficacy. The search for and validation of immunogenic antigen targets increased dramatically over the past few decades and, with the advent of modern sequencing techniques, permitting the fast and accurate identification of the neoantigen landscape of tumor cells, will undoubtedly continue to grow exponentially for years to come. We have previously implemented Variable Epitope Libraries (VEL) as an unconventional vaccine strategy in preclinical models and for identifying and selecting mutant epitope variants. Here, we used an alanine-based sequence to generate a 9-mer VEL-like combinatorial mimotope library G3d as a new class of vaccine immunogen. An in silico analysis of the 16,000 G3d-derived sequences revealed potential MHC-I binders and immunogenic mimotopes. We demonstrated the antitumor effect of treatment with G3d in the 4T1 murine model of breast cancer. Moreover, two different T cell proliferation screening assays against a panel of randomly selected G3d-derived mimotopes allowed the isolation of both stimulatory and inhibitory mimotopes showing differential therapeutic vaccine efficacy. Thus, the mimotope library is a promising vaccine immunogen and a reliable source for isolating molecular cancer vaccine components.

Imunização de camundongos LDLr-/- com peptídeo mimético da LDL eletronegativa: uma potencial estratégia terapêutica para a aterosclerose / Immunization of LDLr - / - mice with electronegative LDL mimetic peptides: a potential therapeutic strategy for atherosclerosis

Introdução: A aterosclerose é uma doença inflamatória crônica decorrente de alterações na parede das artérias de médio e grande calibre e associadas a diversos fatores de risco, dentre os quais destaca-se as hiperlipidemias, ou seja, o aumento plasmático das lipoproteínas, mas também outras comorbidades, como a Síndrome Metabólica. Entre as lipoproteínas, a lipoproteína de baixa densidade (LDL) é de grande relevância na aterosclerose. Diferentes espécies de LDL modificada (LDLm) são originadas através de lipólise, glicação e proteólise, além da oxidação, variando em densidade e eletronegatividade, sendo melhor denominada LDL eletronegativa [LDL (-)]. Considerando as diferenças conformacionais entre a estrutura da ApoB-100 da LDL nativa e da LDL (-), em um estudo inicial, nosso grupo desenvolveu um anticorpo monoclonal (2C7) a partir da imunização de camundongos Balb/c com a LDL (-) humana. Em uma etapa seguinte foi mapeado o epítopo reconhecido pelo anticorpo monoclonal anti-LDL (-) através de phage display. O peptídeo ligante do anticorpo monoclonal anti-LDL (-) foi nomeado p2C7. Esse peptídeo não representa regiões da sequência linear da ApoB-100 humana, mas microdomínios conformacionais de epítopos da ApoB-100 da LDL (-), tornando-os candidatos para a imunomodulação da aterogênese. Portanto, investigar a imunomodulação induzida pelos peptídeo p2C7 miméticos da LDL (-), por representar um epítopo imunodominante da LDL (-), poderá abrir novas perspectivas terapêuticas futuras para a imunomodulação da aterosclerose. Objetivo: Avaliar a imunomodulação promovida pelo p2C7 in vivo, utilizando camundongos C57BL/6 LDLr -/- e amostras de plasma humano. Adicionalmente, no estágio (BEPE) realizado no Instituto Karolinska (dezembro de 2019 a março de 2021), investigou-se o imunometabolismo como mediador nas doenças cardiovasculares. Na parte II-A, estão descritos os resultados do estudo inicialmente proposto. Na parte II-B, apresenta-se os resultados que foram desenvolvidos posteriormente, com ampliação do escopo do projeto, abordando-se a inflamação vascular envolvida no aneurisma de aorta abdominal através de ferramentas de bioinformática. Na parte II-C, são apresentados os resultados do estudo do envolvimento da enzima indolamina 2,3 dioxigenase (IDO) na esteatohepatite não-alcoólica (NASH) e aterosclerose em camundongos ApoE-/- and ApoE/IDO/double-knockout. Metodologia: Foi avaliada a presença de anticorpos anti-p2C7 em amostras de plasma humano de indivíduos com ou sem síndrome metabólica. Realizamos a determinação de TNF circulante nas mesmas amostras e prosseguimos com regressões lineares associando os parâmetros inflamatórios com os níveis de anticorpos anti-p2C7. Camundongos C57BL/6 LDLr -/- foram imunizados com p2C7 e os adjuvantes Alum ou Montanide ISA 720, analisando-se os títulos de anticorpos contra p2C7 e LDL (-), a produção de citocinas (IL-10, IL-4, IL-2, IL-6, IFNγ, IL-17, TNFα) e células secretoras de anticorpos. Camundongos C57BL/6 LDLr -/- foram tolerizados contra os peptídeos mimotopos, com injeções intravenosas (veia caudal) e desafiados com a imunização contendo LDL (-) + Alum. Avaliou-se os títulos de anticorpos contra p2C7 e LDL (-) e a produção de citocinas (TNF-α, IFNγ, IL-12, IL-6, IL-10 e MCP-1). Os camundongos foram mantidos em dieta hipercolesterolêmica por 3 meses para formação da placa aterosclerótica. Após este período, os camundongos foram eutanasiados, avaliando-se a formação de placa aterosclerótica na artéria abdominal e arco aórtico, assim como a produção de citocinas (TNF-α, IFNγ, IL-12, IL-6, IL-10 e MCP-1). Camundongos C57BL/6 LDLr -/- foram imunizados com OVA-p2C7 e, após dieta hipercolesterolêmica de 3 meses para formação de placa aterosclerótica, foram avaliados os parâmetros inflamatórios e avaliada a captação de 18F-FDG no arco aórtico através de PET/CT. Resultados: A imunização com o p2C7 (livre) não foi capaz de induzir resposta humoral, não se observando títulos detectáveis de anticorpos reativos à p2C7 ou LDL (-) em nenhum camundongo imunizado, assim como não foram detectadas células secretoras de anticorpos específicos para a LDL (-). O grupo imunizado com Alum ou Montanide + p2C7 teve aumento significativo na produção de TNF- quando comparado com os demais grupos. O protocolo de tolerização foi realizado com sucesso, visto que os camundongos tolerizados apresentaram títulos de anticorpos inferiores aos controles para o epítopo utilizado. Apenas os camundongos tolerizados com o p2C7 apresentaram aumento significativo na produção de IL-6, IL-12, IL-10, TNF-α, IFNγ e MCP 1 após dieta hipercolesterolêmica. A imunização ativa com OVA-p2C7 foi capaz de reduzir a produção de TNF induzida pela dieta hipercolesterolêmica, assim como reduzir a captação de 18F-FDG. Conclusão: o epítopo p2C7 é altamente expresso na LDL (-) de pacientes com maior risco cardiovascular. Além disso, a imunização ativa com p2C7 também se mostra uma ferramenta promissora para prevenir e regular a inflamação causada pela LDL (-) no curso da aterosclerose

Introduction: Atherosclerosis is a chronic inflammatory disease resulting from changes in the wall of medium and large-caliber arteries and associated with several risk factors, among which hyperlipidemias stand out, ie, the increase in plasma lipoproteins, but also other comorbidities, such as Metabolic Syndrome. Among the lipoproteins, low-density lipoprotein (LDL) is of great relevance in atherosclerosis. Different isoforms of modified LDL (LDLm) are originated through lipolysis, glycation and proteolysis, in addition to oxidation, varying in density and electronegativity, being better called electronegative LDL [LDL (-)]. Considering the conformational differences between the ApoB-100 structure of native LDL and LDL (-), in an initial study, our group developed a monoclonal antibody (2C7) from the immunization of Balb/c mice with human LDL (-). In a next step, the epitope recognized by the anti-LDL monoclonal antibody (-) was mapped using phage display. The binding peptide of anti-LDL monoclonal antibodies (-) was named p2C7. This peptide does not represent linear sequence regions of human ApoB-100, but conformational microdomains of LDL (-) ApoB-100 epitopes, making them candidates for the immunomodulation of atherogenesis. Therefore, investigating the immunomodulation induced by p2C7 peptide mimetics of LDL (-) as it represents an immunodominant epitope of LDL (-) could open new future therapeutic perspectives for the immunomodulation of atherosclerosis. Objective: To evaluate the immunomodulation promoted by p2C7 in vivo, using C57BL/6 LDLr -/- mice, and human plasma samples. In addition, in the internship (BEPE), held at the Karolinska Institute (December 2019 to March 2021), immunometabolism as a mediator of Cardiovascular Diseases was studied. In part II-A, the results of the initially proposed study are described. In part II-B, the results that were developed later are presented, expanding the scope of the project, approaching the vascular inflammation involved in the abdominal aortic aneurysm through bioinformatics tools. In part II-C, the results of the study of the involvement of the enzyme indoleamine 2,3 dioxygenase (IDO) in non-alcoholic steatohepatitis (NASH) and atherosclerosis in ApoE-/- and ApoE/IDO/double mice are presented -knockout. Methodology: The presence of anti-p2C7 antibodies in human plasma samples with or without Metabolic Syndrome was evaluated. We measured circulating TNF in the same samples and proceeded with linear regressions associating inflammatory parameters with levels of anti-p2C7 antibodies. C57BL/6 LDLr -/- mice were immunized with p2C7 and the adjuvants Alum or Montanide ISA 720, analyzing the antibody titers against p2C7 and LDL (-), the production of cytokines (IL-10, IL-4, IL -2, IL-6, IFNγ, IL-17, TNFα) and antibody-secreting cells. C57BL/6 LDLr -/- mice were tolerized against mimotope peptides with intravenous injections (caudal vein) and challenged with immunization containing LDL (-) + Alum. Antibody titers against p2C7 and LDL (-) and cytokine production (TNF-α, IFNγ, IL-12, IL-6, IL-10 and MCP-1) were evaluated. The mice were kept on a hypercholesterolemic diet for 3 months for atherosclerotic plaque formation. After this period, the mice were euthanized, evaluating the formation of atherosclerotic plaque in the abdominal artery and aortic arch, as well as the production of cytokines (TNF-α, IFNγ, IL-12, IL-6, IL-10 and MCP -1). C57BL/6 LDLr -/- mice were immunized with OVA-p2C7 and, after a 3-month hypercholesterolemic diet for atherosclerotic plaque formation, inflammatory parameters were evaluated and 18F-FDG uptake was evaluated by PET/CT. Results: Immunization with p2C7 (free) was not able to induce a humoral response, with no detectable titers of antibodies reactive to p2C7 or LDL (-) being observed in any immunized mouse, as well as no detectable antibody-secreting cells for the LDL (-). The group immunized with Alum or Montanide + p2C7 had a significant increase in TNF-α production when compared to the other groups. The tolerance protocol was successfully performed, as the tolerized mice had lower antibody titers than controls for the epitope used. Only mice tolerated with p2C7 showed a significant increase in the production of IL-6, IL-12, IL-10, TNF-α, IFNγ and MCP 1 after a hypercholesterolemic diet. Active immunization with OVA-p2C7 was able to reduce TNF production induced by the hypercholesterolemic diet, as well as to reduce 18F-FDG uptake. Conclusion: the p2C7 epitope is highly expressed in LDL (-) of patients with higher cardiovascular risk. Furthermore, active immunization with p2C7 is also a promising tool to prevent and regulate inflammation caused by LDL (-) in the course of atherosclerosis

Imunização de camundongos LDLr-/- com peptídeo mimético da LDL eletronegativa: uma potencial estratégia terapêutica para a ateroscleros / Immunization of LDLr - / - mice with electronegative LDL mimetic peptides: a potential therapeutic strategy for atherosclerosis

Introdução: A aterosclerose é uma doença inflamatória crônica decorrente de alterações na parede das artérias de médio e grande calibre e associadas a diversos fatores de risco, dentre os quais destaca-se as hiperlipidemias, ou seja, o aumento plasmático das lipoproteínas, mas também outras comorbidades, como a Síndrome Metabólica. Entre as lipoproteínas, a lipoproteína de baixa densidade (LDL) é de grande relevância na aterosclerose. Diferentes espécies de LDL modificada (LDLm) são originadas através de lipólise, glicação e proteólise, além da oxidação, variando em densidade e eletronegatividade, sendo melhor denominada LDL eletronegativa [LDL (-)]. Considerando as diferenças conformacionais entre a estrutura da ApoB-100 da LDL nativa e da LDL (-), em um estudo inicial, nosso grupo desenvolveu um anticorpo monoclonal (2C7) a partir da imunização de camundongos Balb/c com a LDL (-) humana. Em uma etapa seguinte foi mapeado o epítopo reconhecido pelo anticorpo monoclonal anti-LDL (-) através de phage display. O peptídeo ligante do anticorpo monoclonal anti-LDL (-) foi nomeado p2C7. Esse peptídeo não representa regiões da sequência linear da ApoB-100 humana, mas microdomínios conformacionais de epítopos da ApoB-100 da LDL (-), tornando-os candidatos para a imunomodulação da aterogênese. Portanto, investigar a imunomodulação induzida pelos peptídeo p2C7 miméticos da LDL (-), por representar um epítopo imunodominante da LDL (-), poderá abrir novas perspectivas terapêuticas futuras para a imunomodulação da aterosclerose. Objetivo: Avaliar a imunomodulação promovida pelo p2C7 in vivo, utilizando camundongos C57BL/6 LDLr -/- e amostras de plasma humano. Adicionalmente, no estágio (BEPE) realizado no Instituto Karolinska (dezembro de 2019 a março de 2021), investigou-se o imunometabolismo como mediador nas doenças cardiovasculares. Na parte II-A, estão descritos os resultados do estudo inicialmente proposto. Na parte II-B, apresenta-se os resultados que foram desenvolvidos posteriormente, com ampliação do escopo do projeto, abordando-se a inflamação vascular envolvida no aneurisma de aorta abdominal através de ferramentas de bioinformática. Na parte II-C, são apresentados os resultados do estudo do envolvimento da enzima indolamina 2,3 dioxigenase (IDO) na esteatohepatite não-alcoólica (NASH) e aterosclerose em camundongos ApoE-/- and ApoE/IDO/double-knockout. Metodologia: Foi avaliada a presença de anticorpos anti-p2C7 em amostras de plasma humano de indivíduos com ou sem síndrome metabólica. Realizamos a determinação de TNF circulante nas mesmas amostras e prosseguimos com regressões lineares associando os parâmetros inflamatórios com os níveis de anticorpos anti-p2C7. Camundongos C57BL/6 LDLr -/- foram imunizados com p2C7 e os adjuvantes Alum ou Montanide ISA 720, analisando-se os títulos de anticorpos contra p2C7 e LDL (-), a produção de citocinas (IL-10, IL-4, IL-2, IL-6, IFNγ, IL-17, TNFα) e células secretoras de anticorpos. Camundongos C57BL/6 LDLr -/- foram tolerizados contra os peptídeos mimotopos, com injeções intravenosas (veia caudal) e desafiados com a imunização contendo LDL (-) + Alum. Avaliou-se os títulos de anticorpos contra p2C7 e LDL (-) e a produção de citocinas (TNF-α, IFNγ, IL-12, IL-6, IL-10 e MCP-1). Os camundongos foram mantidos em dieta hipercolesterolêmica por 3 meses para formação da placa aterosclerótica. Após este período, os camundongos foram eutanasiados, avaliando-se a formação de placa aterosclerótica na artéria abdominal e arco aórtico, assim como a produção de citocinas (TNF-α, IFNγ, IL-12, IL-6, IL-10 e MCP-1). Camundongos C57BL/6 LDLr -/- foram imunizados com OVA-p2C7 e, após dieta hipercolesterolêmica de 3 meses para formação de placa aterosclerótica, foram avaliados os parâmetros inflamatórios e avaliada a captação de 18F-FDG no arco aórtico através de PET/CT. Resultados: A imunização com o p2C7 (livre) não foi capaz de induzir resposta humoral, não se observando títulos detectáveis de anticorpos reativos à p2C7 ou LDL (-) em nenhum camundongo imunizado, assim como não foram detectadas células secretoras de anticorpos específicos para a LDL (-). O grupo imunizado com Alum ou Montanide + p2C7 teve aumento significativo na produção de TNF- quando comparado com os demais grupos. O protocolo de tolerização foi realizado com sucesso, visto que os camundongos tolerizados apresentaram títulos de anticorpos inferiores aos controles para o epítopo utilizado. Apenas os camundongos tolerizados com o p2C7 apresentaram aumento significativo na produção de IL-6, IL-12, IL-10, TNF-α, IFNγ e MCP 1 após dieta hipercolesterolêmica. A imunização ativa com OVA-p2C7 foi capaz de reduzir a produção de TNF induzida pela dieta hipercolesterolêmica, assim como reduzir a captação de 18F-FDG. Conclusão: o epítopo p2C7 é altamente expresso na LDL (-) de pacientes com maior risco cardiovascular. Além disso, a imunização ativa com p2C7 também se mostra uma ferramenta promissora para prevenir e regular a inflamação causada pela LDL (-) no curso da aterosclerose

Introduction: Atherosclerosis is a chronic inflammatory disease resulting from changes in the wall of medium and large-caliber arteries and associated with several risk factors, among which hyperlipidemias stand out, ie, the increase in plasma lipoproteins, but also other comorbidities, such as Metabolic Syndrome. Among the lipoproteins, low-density lipoprotein (LDL) is of great relevance in atherosclerosis. Different isoforms of modified LDL (LDLm) are originated through lipolysis, glycation and proteolysis, in addition to oxidation, varying in density and electronegativity, being better called electronegative LDL [LDL (-)]. Considering the conformational differences between the ApoB-100 structure of native LDL and LDL (-), in an initial study, our group developed a monoclonal antibody (2C7) from the immunization of Balb/c mice with human LDL (-). In a next step, the epitope recognized by the anti-LDL monoclonal antibody (-) was mapped using phage display. The binding peptide of anti-LDL monoclonal antibodies (-) was named p2C7. This peptide does not represent linear sequence regions of human ApoB-100, but conformational microdomains of LDL (-) ApoB-100 epitopes, making them candidates for the immunomodulation of atherogenesis. Therefore, investigating the immunomodulation induced by p2C7 peptide mimetics of LDL (-) as it represents an immunodominant epitope of LDL (-) could open new future therapeutic perspectives for the immunomodulation of atherosclerosis. Objective: To evaluate the immunomodulation promoted by p2C7 in vivo, using C57BL/6 LDLr -/- mice, and human plasma samples. In addition, in the internship (BEPE), held at the Karolinska Institute (December 2019 to March 2021), immunometabolism as a mediator of Cardiovascular Diseases was studied. In part II-A, the results of the initially proposed study are described. In part II-B, the results that were developed later are presented, expanding the scope of the project, approaching the vascular inflammation involved in the abdominal aortic aneurysm through bioinformatics tools. In part II-C, the results of the study of the involvement of the enzyme indoleamine 2,3 dioxygenase (IDO) in non-alcoholic steatohepatitis (NASH) and atherosclerosis in ApoE-/- and ApoE/IDO/double mice are presented -knockout. Methodology: The presence of anti-p2C7 antibodies in human plasma samples with or without Metabolic Syndrome was evaluated. We measured circulating TNF in the same samples and proceeded with linear regressions associating inflammatory parameters with levels of anti-p2C7 antibodies. C57BL/6 LDLr -/- mice were immunized with p2C7 and the adjuvants Alum or Montanide ISA 720, analyzing the antibody titers against p2C7 and LDL (-), the production of cytokines (IL-10, IL-4, IL -2, IL-6, IFNγ, IL-17, TNFα) and antibody-secreting cells. C57BL/6 LDLr -/- mice were tolerized against mimotope peptides with intravenous injections (caudal vein) and challenged with immunization containing LDL (-) + Alum. Antibody titers against p2C7 and LDL (-) and cytokine production (TNF-α, IFNγ, IL-12, IL-6, IL-10 and MCP-1) were evaluated. The mice were kept on a hypercholesterolemic diet for 3 months for atherosclerotic plaque formation. After this period, the mice were euthanized, evaluating the formation of atherosclerotic plaque in the abdominal artery and aortic arch, as well as the production of cytokines (TNF-α, IFNγ, IL-12, IL-6, IL-10 and MCP -1). C57BL/6 LDLr -/- mice were immunized with OVA-p2C7 and, after a 3-month hypercholesterolemic diet for atherosclerotic plaque formation, inflammatory parameters were evaluated and 18F-FDG uptake was evaluated by PET/CT. Results: Immunization with p2C7 (free) was not able to induce a humoral response, with no detectable titers of antibodies reactive to p2C7 or LDL (-) being observed in any immunized mouse, as well as no detectable antibody-secreting cells for the LDL (-). The group immunized with Alum or Montanide + p2C7 had a significant increase in TNF-α production when compared to the other groups. The tolerance protocol was successfully performed, as the tolerized mice had lower antibody titers than controls for the epitope used. Only mice tolerated with p2C7 showed a significant increase in the production of IL-6, IL-12, IL-10, TNF-α, IFNγ and MCP 1 after a hypercholesterolemic diet. Active immunization with OVA-p2C7 was able to reduce TNF production induced by the hypercholesterolemic diet, as well as to reduce 18F-FDG uptake. Conclusion: the p2C7 epitope is highly expressed in LDL (-) of patients with higher cardiovascular risk. Furthermore, active immunization with p2C7 is also a promising tool to prevent and regulate inflammation caused by LDL (-) in the course of atherosclerosis

Biopanning the mimotopes of aflatoxin B1 and their immunogenicity / Panning de mimotopo aflatoxina B1 e sua imunogenicidade

Utilizando um anticorpo monoclonal contra a aflatoxina B1 (AFB1) como ligante, foi identificado um mimotopo específico de aflatoxina B1 após se realizarem quatro ciclos de seleção biológica de 7-peptídeos aleatórios em biblioteca de fago exibida. O mimotopo é denominado P10, e sua sequência de aminoácidos é YRRHEKD. O soro imunológico de ratos Balb/c imunizados com P10 foi especificamente ligado à aflatoxina B1-albumina, indicando que o anticorpo era específico ao AFB1. Esses resultados sugerem que é possível desenvolver a vacina baseada em mimotopo associado à toxina.(AU)

Biopanning the mimotopes of aflatoxin B1 and their immunogenicity / Panning de mimotopo aflatoxina B1 e sua imunogenicidade

Utilizando um anticorpo monoclonal contra a aflatoxina B1 (AFB1) como ligante, foi identificado um mimotopo específico de aflatoxina B1 após se realizarem quatro ciclos de seleção biológica de 7-peptídeos aleatórios em biblioteca de fago exibida. O mimotopo é denominado P10, e sua sequência de aminoácidos é YRRHEKD. O soro imunológico de ratos Balb/c imunizados com P10 foi especificamente ligado à aflatoxina B1-albumina, indicando que o anticorpo era específico ao AFB1. Esses resultados sugerem que é possível desenvolver a vacina baseada em mimotopo associado à toxina.(AU)

Inflammasome Activation in Human Macrophages Induced by a LDL (-) Mimetic Peptide.

The inflammasome is responsible for maturation of interleukin-1ß (IL-1ß) and interleukin-18 (IL-18) contributing to the inflammatory process in atherosclerosis. It is shown here that an electronegative low-density lipoprotein [LDL (-)] apoB-100 mimetic peptide can activate the transcriptional and posttranslational signs needed for complete inflammasome activation. This peptide, named p2C7, can activate the Toll-like receptor 4 (TLR4) that induces NF-κB activation and the transcription of inflammasome components. After blocking TLR4 with a neutralizing antibody, inflammasome component (NLRP3, CASP1, and ASC) and IL1b and IL18 gene downregulation occurred in human-derived macrophages stimulated with p2C7 or LDL (-). Moreover, the posttranslational signal was activated by the interaction between p2C7 and the lectin-type oxidized LDL receptor 1 (LOX-1), as demonstrated by the induction of caspase-1 cleavage in macrophages. The blockage of either TLR4 or LOX-1 decreased IL-1ß and IL-18 secretion by human-derived macrophages as both pathways are necessary for complete inflammasome activation. These findings suggest a mechanism by which macrophages transduce the pro-inflammatory signal provided by LDL (-) ApoB-100 and its mimetic peptides to activate the inflammasome protein complex what may be relevant for the inflammatory process in atherosclerosis.

Proinflammatory Action of a New Electronegative Low-Density Lipoprotein Epitope.

The electronegative low-density lipoprotein, LDL (-), is an endogenously modified LDL subfraction with cytotoxic and proinflammatory actions on endothelial cells, monocytes, and macrophages contributing to the progression of atherosclerosis. In this study, epitopes of LDL (-) were mapped using a phage display library of peptides and monoclonal antibodies reactive to this modified lipoprotein. Two different peptide libraries (X6 and CX8C for 6- and 8-amino acid-long peptides, respectively) were used in the mapping. Among all tested peptides, two circular peptides, P1A3 and P2C7, were selected based on their high affinities for the monoclonal antibodies. Small-angle X-ray scattering analysis confirmed their structures as circular rings. P1A3 or P2C7 were quickly internalized by bone marrow-derived murine macrophages as shown by confocal microscopy. P2C7 increased the expression of TNFα, IL-1 ß and iNOS as well as the secretion of TNFα, CCL2, and nitric oxide by murine macrophages, similar to the responses induced by LDL (-), although less intense. In contrast, P1A3 did not show pro-inflammatory effects. We identified a mimetic epitope associated with LDL (-), the P2C7 circular peptide, that activates macrophages. Our data suggest that this conformational epitope represents an important danger-associated molecular pattern of LDL (-) that triggers proinflammatory responses.

Engineered biomarkers for leprosy diagnosis using labeled and label-free analysis.

The biotechnological evolution towards the development of antigens to detect leprosy has been progressing. However, the identification of leprosy in paucibacillary patients, based solely on the antigen-antibody interaction still remains a challenge. The complexity of clinical manifestations requires innovative approaches to improve the sensitivity of assays to detect leprosy before the onset of symptoms, thus avoiding disabilities and contributing, indirectly, to reduce transmission. In this study, the strategies employed for early leprosy diagnosis were: i. using a phage-displayed mimotope (APDDPAWQNIFNLRR) which mimics an immunodominant sequence (PPNDPAWQRNDPILQ) of an antigen of Mycobacterium leprae known as Ag85B; ii. engineering the mimotope by adding a C-terminal flexible spacer (SGSG-C); iii. conjugating the mimotope to a carrier protein to provide better exposure to antibodies; iv. amplifying the signal using biotin-streptavidin detection system in an ELISA; and v. coating the optimized mimotope on a quartz crystal microbalance (QCM) sensor for label-free biosensing. The ELISA sensitivity increased up to 91.7% irrespective of the immunological profile of the 132 patients assayed. By using comparative modeling, the M. tuberculosis Ag85B was employed as a template to ascertain which features make the mimotope a good antigen in terms of its specificity. For the first time, a sensitive QCM-based immunosensor to detect anti M. leprae antibodies in human serum was used. M. leprae antibodies could also be detected in the sera of paucibacillary patients; thus, the use of a mimotope-derived synthetic peptide as bait for antibodies in a novel analytical label-free immunoassay for leprosy diagnosis exhibits great potential.

Antitumor activity and carrier properties of novel hemocyanins coupled to a mimotope of GD2 ganglioside.

Conjugation to carrier proteins is a way to improve the immunogenicity of peptides. Such is the case for peptides mimicking carbohydrate tumor-associated antigens in cancer vaccine development. The most used protein for this purpose is the keyhole limpet hemocyanin (KLH) from Megathura crenulata. Its limited bioavailability has prompted interest in finding new candidates; nevertheless, it is not known whether other hemocyanins might be equally efficient as carrier of carbohydrate peptide mimotopes to promotes anti-tumor responses. Here, we evaluated the carrier and antitumor activity of novel hemocyanins with documented immunogenicity obtained from Concholepas concholepas (CCH) and Fissurella latimarginata (FLH), coupled through sulfo-SMCC to P10, a mimetic peptide of GD2, the major ganglioside constituent of neuroectodermal tumors, and incorporating AddaVax as an adjuvant. The humoral immune responses of mice showed that CCH-P10 and FLH-P10 conjugates elicited specific IgM and IgG antibodies against P10 mimotope, similar to those obtained with KLH-P10, which was used as a positive control. The CCH-P10 and FLH-P10 antisera, exhibited cross-reactivity with murine and human melanoma cells, like anti-CCH and anti-FLH sera suggesting a cross-reaction of CCH and FLH glycosylations with carbohydrate epitopes on the tumor cell surfaces, similar to the KLH antisera. When mice were primed with each hemocyanin-P10 and challenged with melanoma cells, better antitumor effects were observed for FLH-P10 than for CCH-P10 and, as for KLH-P10, irrespective of conjugation. These data demonstrate that CCH and FLH are useful carriers of carbohydrate mimotopes; however, the best antitumor activity of FLH preparations, indicate that is a suitable candidate for further cancer vaccines research.

Physicochemical and immunological characterization of chitosan-coated bacteriophage nanoparticles for in vivo mycotoxin modeling.

To propose a novel modeling of aflatoxin immunization and surrogate toxin conjugate from AFB1 vaccines, an immunogen based on the mimotope, (i.e. a peptide-displayed phage that mimics aflatoxins epitope without toxin hazards) was designed. The recombinant phage 3P30 was identified by phage display technology and exhibited the ability to bind, dose dependent, specifically to its cognate target - anti-AFB1 antibody. In immunization assay, the phage-displayed mimotope and its peptide chemically synthesized were able to induce specific anti-AFB1 antibodies, indicating the proof of concept for aflatoxin mimicry. Furthermore, the phage 3P30 was homogeneously coated with chitosan, which also provided a tridimensional matrix network for mucosal delivery. After intranasal immunization, chitosan coated phages improved specific immunogenicity compared to the free antigen. It can be concluded that affinity-selected phage may contribute to the rational design of epitope-based vaccines in a prospectus for the control of aflatoxins and possibly other mycotoxins, and that chitosan coating improved the vectorization of the vaccine by the mucosal route.

Estudos de aterosclerose experimental utilizando tomografia por emissão de pósitrons ( PET-Scan ) / Studies of experimental atherosclerosis using pósitron emission tomography ( PET-Scan )

A aterosclerose é caracterizada como uma doença imune-inflamatória crônica das artérias devido ao grande acúmulo de lipídios na íntima. Um dos fatores envolvidos na progressão da aterosclerose é a presença de uma subfração de partículas de lipoproteína de baixa densidade (LDL) com um grau mínimo de modificação, denominada LDL eletronegativa [LDL(-)], que possui propriedades pró-inflamatórias, apresenta maior retenção na íntima das artérias e maior tempo de permanência na circulação sanguínea, gerando respostas imuno-inflamatórias. Epítopos de anticorpos monoclonais importantes no reconhecimento das partículas de LDL(-) foram mapeados por phage display, gerando peptídeos mimotopos (P1A3 e P2C7) com potencial para acompanhamento da progressão da aterosclerose, sendo excelentes candidatos como radiotraçadores marcados com emissores de pósitrons para obtenção de imagens moleculares por tomografia por emissão de pósitrons (PET) associada à tomografia computadorizada (PET/CT). O peptídeo P1A3 foi radiomarcado com 64Cu através da complexação com o quelante DOTA, obtendo-se imagens por PET/CT da captação do peptídeo na região do arco aórtico de camundongos knockout para a apolipoproteína E (Apoe-/-) comparados com animais controle sem lesões ateroscleróticas. Antes da obtenção das imagens PET/CT, os peptídeos radiomarcados foram validados através de estudos de estabilidade e biodistribuição, acumulando-se rapidamente nos rins. Também foi sintetizado um nanocluster de ouro, marcado com 64Cu e funcionalizado com P1A3 em sua superfície, observando-se o maior direcionamento dos nanoclusters de ouro ligados ao P1A3 para a região das lesões ateroscleróticas do arco aórtico de camundongos Apoe-/-, comparado ao nanocluster controle. Os peptídeos P1A3 e P2C7 radiomarcados com 68Ga, foram também avaliados por imagens PET/CT em camundongos knockout para o gene do receptor da LDL (LDLr-/-) tratados ou não com dieta hipercolesterolêmica. As imagens PET/CT mostraram que os peptídeos marcados com 68Ga tiveram um aumento de captação na região do arco aórtico de camundongos LDLr-/- hipercolesterolêmicos em relação ao controle. Além disso, P2C7 foi radiomarcado com 99mTc e sua biodistribuição demonstrou uma relação maior de % atividade injetada (AI)/órgão da aorta/coração nos camundongos hipercolesterolêmicos, em concordância com a imagem obtida por SPECT (tomografia computadorizada por emissão de fóton único) que revelou maior captação no arco aórtico

Atherosclerosis is characterized as a chronic immune-inflammatory disease of the large arteries due to the accumulation of lipids in the intima. One of the factors involved in the progression of atherosclerosis is the presence of a subfraction of low-density lipoprotein (LDL) particles with a minimum degree of modification, called electronegative LDL [LDL (-)], which has proinflammatory properties, retention in the intima of the arteries and longer residence time in the blood circulation, generating immune-inflammatory responses. Epitopes of monoclonal antibodies important for the recognition of LDL(-) particles were mapped by phage display, generating mimotope peptides (P1A3 and P2C7) with potential to monitor the progression of atherosclerosis. These peptides are excellent candidates as radiotracers labeled with positron emitters to obtain molecular images by positron emission tomography (PET) associated with computed tomography (PET/CT). The P1A3 peptide was radiolabeled with 64Cu by complexation with the DOTA chelator to obtain PET/CT images of the peptide uptake in the aortic arch of apoliprotein E knockout mice (Apoe-/-) compared to control animals without atherosclerotic lesions. Prior to PET/CT imaging, radiolabeled peptides were validated by stability and biodistribution studies that indicated rapid accumulation in the kidneys. It was also synthesized a gold nanocluster, labeled with 64Cu and functionalized with P1A3 on its surface, observing the greater targeting of gold nanoclusters bound to P1A3 in the region of the atherosclerotic lesions of the aortic arch of Apoe-/- mice, compared to control nanocluster. The P1A3 and P2C7 peptides radiolabeled with 68Ga were also evaluated by PET imaging in LDL receptor gene knockout mice (LDLr-/-) treated or not with a hypercholesterolemic diet. PET/CT images showed that the 68Ga-labeled peptides had increased uptake in aortic arch of LDLr-/- hypercholesterolemic mice in relation to the control. Furthermore, the biodistribution of 99mTc-radiolabeled P2C7 showed a higher %ID (injected dose)/organ ratio of aorta/heart in hypercholesterolemic mice that was in accordance to SPECT (single photon emission computed tomography) imaging showing its higher uptake in the aortic arch

Strategies for Vaccine Design Using Phage Display-Derived Peptides.

Development of peptide vaccines through the phage display technology is a powerful strategy that relies on short peptides expressed in the phage capsid surface to induce highly targeted immune responses. Phage display-derived immunogenic peptides can be used directly as a phage-fused peptide reagent or as a synthetic peptide with specific modifications, according to target molecule and disease pathogen/parasite. Peptides' selection (mimotopes) can be performed against monoclonal or polyclonal antibodies to disclose determinant regions (epitopes) that can induce a neutralizing response. Validations of mimotopes are performed in vitro and in vivo, based on cell culture and animal models, to demonstrate its immunogenic potential for final vaccine formulations with an appropriate adjuvant. Here we present specific methods for the discovery of novel immunogenic peptides based on phage display.

Characterization of a monoclonal antibody that specifically inhibits triosephosphate isomerase activity of Taenia solium.

In the present study, we obtained and characterized partially a monoclonal antibody (4H11D10B11 mAb) against triosephosphate isomerase from Taenia solium (TTPI). This antibody recognized the enzyme by both ELISA and western blot and was able to inhibit its enzymatic activity in 74%. Moreover, the antigen-binding fragments (Fabs), products of digestion of the monoclonal antibody with papain, retained almost the same inhibitory effect. We determined the binding site by ELISA; synthetic peptides containing sequences from different non-conserved regions of the TTPI were confronted to the 4H11D10B11 mAb. The epitope recognized by the monoclonal antibody was located on peptide TTPI-56 (ATPAQAQEVHKVVRDWIRKHVDAGIADKARI), and an analysis of mimotopes, obtained with the 4H11D10B11 mAb, suggests that the epitope spans the sequence WIRKHVDAGIAD, residues 193-204 of the enzyme. This epitope is located within helix 6, next to loop 6, an essential active loop during catalysis. The antibody did not recognize triosephosphate isomerase from man and pig, definitive and intermediary hosts of T. solium, respectively. Furthermore, it did not bind to the catalytic site, since kinetic analysis demonstrated that inhibition had a non-competitive profile.