Respuesta inmune contra SARS-CoV-2 en personas con VIH convalecientes de COVID-19 / SARS-CoV-2 immunity in PWH

Desde principios de la pandemia de SARS-CoV-2 se ha debatido el curso de la enfermedad COVID-19 en personas con VIH. Por un lado, la inmunodeficiencia derivada de la infección por VIH y la mayor prevalencia de comorbilidades estarían asociadas al desarrollo de enfermedad grave. Por otro lado, la disfunción inmunológica podría evitar una respuesta inflamatoria exacerbada. En este trabajo de revisión analizamos la evidencia disponible en cuanto a la relación entre la manifestación clínica de COVID-19 y la respuesta inmune humoral y celular contra SARS-CoV-2 en el contexto de la coinfección con VIH. La bibliografía sugiere que las personas con VIH que reciben tratamiento antirretroviral logran respuestas eficaces contra SARS-CoV-2, a pesar de presentar algunas de las funciones celulares alteradas. Esto sugiere un impacto significativo de la terapia antirretroviral, no solo en el control del VIH sino en potenciar la inmunidad para restringir otras infecciones.

Since the beginning of SARS-CoV-2 pandemic, the course of COVID-19 in people with HIV has been debated. On the one hand, the immunodeficiency derived from HIV infec-tion and the higher prevalence of comorbidities would be associated with severe disease. On the other hand, due to its immunological dysfunction, an exacerbated inflam-matory response might be avoided.In this review, we analyzed the evidence regarding the clinical manifestation of COVID-19 and the humoral and cellular immune response against SARS-CoV-2 during HIV coinfection. The literature suggests that people with HIV on antiretroviral treatment achieved effective responses against SARS-CoV-2, despite having altered cell func-tions. This indicates a remarkable impact of antiretroviral therapy, not only in controlling HIV but also in boosting immunity to restrict other infections

Intestinal transcriptional profiling reveals fava bean-induced immune response in DBA/1 mice

BACKGROUND: Fava beans (FBs) have long been used as food, and their principal disadvantage is derived from their haemotoxicity. We hypothesized that FB ingestion alters the intestinal gene expression pattern, thereby inducing an immune response. RESULTS: In-depth sequence analysis identified 769 differentially expressed genes (DEGs) associated with the intestine in FB-treated DBA/1 mouse intestines. The identified genes were shown to be associated with biological processes (such as response to stimulus and immune system processes), human disease pathways (such as infectious diseases, endocrine and metabolic diseases, and immune diseases), and organismal system pathways (such as the digestive system, endocrine system, environmental adaptation, and immune system). Moreover, plasma total immunoglobulin E (IgE), histamine, interleukin (IL)-4 and IL-13 levels were significantly increased when the mice were treated with FBs. CONCLUSIONS: These results demonstrated that FBs affect the intestinal immune response and IgE and cytokine secretion in DBA/1 mice.

Immune humoral response of young lambs naturally infested by Oestrus ovis (Diptera: Oestridae) / Resposta imune humoral de cordeiros jovens naturalmente infestados por Oestrus ovis (Diptera: Oestridae)

Abstract Twenty-six newborn lambs were evaluated for 21 weeks, from birth to slaughter, to assess their plasma anti-Oestrus ovis immunoglobulin (IgG) using the ELISA technique. On the last day of sampling, all the lambs were slaughtered and O. ovis larvae were recovered, quantified and identified according to the larval stage. High levels of IgG were observed over the first three weeks of life, thus indicating that antibodies are transferred via colostrum from ewes to lambs. Afterwards, the antibody levels declined progressively until the lambs were 11 weeks of age and subsequently started to increase again when they were around 13 weeks of age, reaching the apex on the last week of sampling. All the lambs were parasitized with different larval stages of O. ovis, with an average of 39 larvae per lamb, and the intensity of the infestation ranged from 10 to 97 larvae. However, there was non-significant correlation coefficients between IgG levels and O. ovis larval burden (P > 0.05). In conclusion, although the lambs became infested with O. ovis at an early age, the larval burden was not associated with specific IgG levels.

Resumo Vinte e seis cordeiros recém-nascidos foram avaliados por 21 semanas, desde o nascimento até o abate, para avaliar os níveis plasmáticos de imunoglobulina (IgG) anti-Oestrus ovis utilizando-se a técnica de ELISA. No último dia de coleta, todos os cordeiros foram abatidos e as larvas de O. ovis foram recuperadas, quantificadas e identificadas de acordo com o estádio larval. Foram observados altos níveis de IgG nas primeiras três semanas de vida, indicando que os anticorpos são transferidos por meio do colostro das ovelhas para os cordeiros. Posteriormente, os níveis de anticorpos diminuíram progressivamente, até os cordeiros completarem 11 semanas de vida. Os níveis de IgG começaram a aumentar novamente a partir de 13 semanas de idade, atingindo o ápice na última semana de coleta. Todos os cordeiros estavam parasitados com diferentes estádios larvais de O. ovis com uma média de 39 larvas por cordeiro, e a intensidade da infestação variou de 10 a 97 larvas. Porém, não houve correlação significativa entre os níveis de IgG e a carga larval de O. ovis (P > 0,05). Em conclusão, embora os cordeiros tenham sido infestados com O. ovis ainda jovens, a carga larval não foi associada a níveis específicos de IgG.

Humoral immune response to measles and varicella vaccination in former very low birth weight preterm infants

ABSTRACT Introduction: Immune response to vaccination in infants born prematurely may be lower than in infants born at full-term. Some clinical factors might be associated with humoral immune response. Objectives: The objectives of this study were to compare the immune response to measles and varicella vaccination in infants born prematurely with those born at full-term and to analyze factors associated with measles and varicella antibody levels. Methods: Prospective study including two groups of infants aged 12 months. One group of infants born prematurely with birth-weight <1500 g and who were in follow-up at the outpatient clinic for preterm infants at the institution and other group of infants born at full-term. Infants with malformations, primary immunodeficiency diseases, born to HIV-positive mothers or who had received plasma or immunoglobulin transfusions five months before or three weeks after vaccination were excluded. Plasma antibodies were measured by ELISA and factors associated with antibody levels were assessed by linear regression. Results: Sixty-five premature and 56 full-term infants were included. The percentage of immune individuals after vaccination against measles (100% vs. 100%) and varicella (92.5% vs. 93.2%) were similar in both groups, as well as the antibody levels against measles (2.393 vs. 2.412 UI/mL; p = 0.970) and varicella (0.551 vs. 0.399 UI/mL; p = 0.114). Use of antenatal corticosteroids decreased measles antibody levels whereas breastfeeding for more than six months increased varicella antibody levels. Conclusions: Humoral responses to measles and varicella were similar between infants born prematurely and full-term infants. Measles antibody levels were negatively associated with antenatal corticosteroid use; varicella antibodies were positively associated with prolonged breastfeeding.

Antígenos MICA y trasplante / MICA antigens and transplantation

Los antígenos leucocitarios humanos (HLA, del inglés human leukocyte antigens), codificados por los genes del complejo principal de histocompatibilidad (MHC, del inglés m ajor histocompatibility complex), actúan como inductores de las respuestas inmunitarias en el trasplante; sin embargo, los productos de los genes relacionados a cadenas MHC clase I (MIC, del inglés MHC class I chain-related genes), constituyen también uno de los blancos del rechazo. La familia de los genes MIC consta de siete miembros, de los cuales solo MICA y MICB son funcionales. Los transcriptos son glicoproteínas de superficie celular de 62 kDA que presentan homología en su secuencia con las moléculas HLA clase I y cuya función está relacionada con la inmunidad innata. En los órganos trasplantados ocurre un incremento en la expresión de los antígenos MICA como una señal temprana de "peligro" debido al trauma quirúrgico y la isquemia. Esta sobrexpresión antigénica puede llevar al rechazo mediado por anticuerpos anti-MICA que activan el complemento y por un incremento de la citotoxicidad debido a la estimulación en los linfocitos citolíticos naturales (NK, del inglés natural killer) y los linfocitos CD8+ &+ αß y γδ, del receptor conocido como NKG2D (NK grupo 2 miembro D(AU)

Human leukocyte antigens (HLA), encoded by major histocompatibility complex (MHC) genes, act as inducers of immune responses in transplantation. However, the products of the genes related to MHC class I chains (MIC) are also one of the targets of rejection. The family of MIC genes consists of seven members, of which only MICA and MICB are functional. Transcripts are cell surface glycoproteins of 62 kDa that exhibit homology in sequence with HLA class I molecules and whose function is related to innate immunity. In transplanted organs an increase in the expression of MICA antigens occurs as an early sign of "danger" due to surgical trauma and ischemia. This antigenic overexpression can lead to rejection mediated by complement-activating anti-MICA antibodies and by increased cytotoxicity due to stimulation in natural killer (NK) lymphocytes and CD8 + + αß and γδ lymphocytes. Receptor known as NKG2D (NK group 2 member D)(AU)

Evaluation of the immunogenicity of Schistosoma mansoni egg surface

Abstract INTRODUCTION Immunogenicity of Schistosoma mansoni egg surface was examined to determine whether intact eggshells have lower antigenicity than ruptured eggs. METHODS: Swiss Webster mice were inoculated with intact or ultrasonicated S. mansoni eggs isolated from infected human feces. Mice were separated into four groups of six animals each and immunizations were performed approximately every 20 days during a 60-day period. Groups 1-4 were administered with saline solution, sonicated eggs with Freund's adjuvant, sonicated eggs without Freund's adjuvant, and intact eggs, respectively. IgG humoral immune response was assessed by ELISA using Soluble Egg Antigen produced from eggs isolated from the livers of infected mice. RESULTS Sonicated eggs co-administered with adjuvant induced the highest humoral response at 58 days, which was 11.9-fold (95% CI 6.2-17.5) greater than the response induced by saline solution. Sonicated eggs without adjuvant induced a 4.3-fold stronger response (95% CI 2.4-6.2) than normal saline. Intact eggs induced humoral response that was nominally twice stronger (95% CI 0.8-3.2) than that induced by normal saline but the effect did not reach statistical significance. CONCLUSIONS Soluble antigens are not abundant on the surface of S. mansoni eggs and/or are not secreted in sufficient quantities to induce a significant immune response to intact eggs. Assuming that isolation procedures had not damaged the eggs used for inoculation, our observations suggest that intact eggs either do not induce a significant immune response or, if they do, the mechanism involves insoluble antigens from the egg surface.

DNA prime-protein boost based vaccination with a conserved region of leptospiral immunoglobulin-like A and B proteins enhances protection against leptospirosis

Leptospirosis is a zoonotic disease caused by pathogenic spirochetes of theLeptospira genus. Vaccination with bacterins has severe limitations. Here, we evaluated the N-terminal region of the leptospiral immunoglobulin-like B protein (LigBrep) as a vaccine candidate against leptospirosis using immunisation strategies based on DNA prime-protein boost, DNA vaccine, and subunit vaccine. Upon challenge with a virulent strain ofLeptospira interrogans, the prime-boost and DNA vaccine approaches induced significant protection in hamsters, as well as a specific IgG antibody response and sterilising immunity. Although vaccination with recombinant fragment of LigBrep also produced a strong antibody response, it was not immunoprotective. These results highlight the potential of LigBrep as a candidate antigen for an effective vaccine against leptospirosis and emphasise the use of the DNA prime-protein boost as an important strategy for vaccine development.

Malaria in pregnant women living in areas of low transmission on the southeast Brazilian Coast: molecular diagnosis and humoural immunity profile

Studies on autochthonous malaria in low-transmission areas in Brazil have acquired epidemiological relevance because they suggest continued transmission in what remains of the Atlantic Forest. In the southeastern portion of the state of São Paulo, outbreaks in the municipality of Juquitiba have been the focus of studies on the prevalence of Plasmodium, including asymptomatic cases. Data on the occurrence of the disease or the presence of antiplasmodial antibodies in pregnant women from this region have not previously been described. Although Plasmodium falciparum in pregnant women has been widely addressed in the literature, the interaction of Plasmodium vivax and Plasmodium malariae with this cohort has been poorly explored to date. We monitored the circulation of Plasmodium in pregnant women in health facilities located in Juquitiba using thick blood film and molecular protocols, as well as immunological assays, to evaluate humoural immune parameters. Through real-time and nested polymerase chain reaction, P. vivax and P. malariae were detected for the first time in pregnant women, with a positivity of 5.6%. Immunoassays revealed the presence of IgG antibodies: 44% for ELISA-Pv, 38.4% for SD-Bioline-Pv and 18.4% for indirect immunofluorescence assay-Pm. The high prevalence of antibodies showed significant exposure of this population to Plasmodium. In regions with similar profiles, testing for a malaria diagnosis might be indicated in prenatal care.

43 kDa and 66 kDa, two blood stage antigens induce immune response in Plasmodium berghei malaria.

The hunt for an effective vaccine against malaria still continues. Several new target antigens as candidates for vaccine design are being explored and tested for their efficacy. In the present study the sera from mice immunized with 24,000 × g fraction of Plasmodium berghei has been used to identify highly immunogenic blood stage antigens. The protective antibodies present in immune sera were covalently immobilized on CNBr activated sepharose 4B and used for affinity chromatography purification of antigens present in blood stages of P. berghei. Two polypeptides of 66 and 43 kDa molecular weights proved to be highly immunogenic. They exhibited a strong humoral immune response in mice as evident by high titres in ELISA and IFA. Protective immunity by these two antigens was apparent by in vivo and in vitro studies. These two proteins could further be analysed and used as antigens in malaria vaccine design.

Serum bactericidal activity as indicator of innate immunity in pacu Piaractus mesopotamicus (Holmberg, 1887) / Atividade bactericida do soro como indicador de imunidade inata de pacu Piaractus mesopotamicus (Holmberg, 1887)

The immune system of teleost fish has mechanisms responsible for the defense against bacteria through protective proteins in several tissues. The protein action can be evaluated by serum bactericidal activity and this is an important tool to analyze the immune system. Pacu, Piaractus mesopotamicus, is one of the most important fish in national aquaculture. However there is a lack of studies on its immune responses. In order to standardize and assess the accuracy of the serum bactericidal activity assay, fish were briefly challenged with Aeromonas hydrophila and sampled one week after the challenge. The bacterial infection increased the concentration of protective proteins, resulting in a decrease of colony-forming unit values expressed as well as an enhanced serum bactericidal activity. The protocol showed a reliable assay, appropriate to determine the serum bactericidal activity of pacu in the present experimental conditions.

O sistema imune de peixes teleósteos tem mecanismos responsáveis pela defesa contra bactérias e atua através de proteínas presentes em diversos tecidos. A ação destas proteínas pode ser avaliada pela atividade bactericida do soro, sendo esta uma importante ferramenta para analisar o sistema imune. O pacu, Piaractus mesopotamicus, é um peixe nativo muito importante para aquicultura nacional, entretanto há pouco conhecimento sobre o funcionamento de seu sistema imune. Assim foi realizado experimento para padronizar e avaliar a eficiência do ensaio de atividade bactericida. Resumidamente, peixes foram desafiados por Aeromonas hydrophila e amostradas uma semana após o desafio. A infecção bacteriana promoveu um aumento na concentração de proteínas protetoras, resultando em diminuição dos valores de unidades formadoras de colônias ou expressos também como aumento da atividade bactericida do soro. O protocolo se mostrou confiável, sendo apropriado para determinar a atividade bactericida do soro de pacu nas condições experimentais.

Genetic polymorphism and immune response to tuberculosis in indigenous populations: a brief review

We systematically reviewed studies of the immune response to tuberculosis and the genetic polymorphisms associated with Th1-or Th2-mediated cytokine expression in indigenous populations. A bibliographic search was performed on the Medline and ISI databases and included studies published between January 1980 and October 2011. The search terms were tuberculosis, American Indians, Amerindian, indigenous, Indians, native people, aboriginal, immun*, host immune, immune response, cytokine*, polymorphism*, and gene. Regardless of their design, studies that evaluated immunoglobulin, cytokine levels and genetic polymorphisms that altered cytokine expression were included. Thirteen studies met the inclusion criteria. The majority of studies were performed in Latin America, and five investigated the Warao ethnic group of Venezuela. Most of the investigations indirectly evaluated the immune response. Higher anergy to the tuberculin skin test, higher IgG4 and IgM levels, higher IL-5 production and lower TNF-a, IL-12p40 and IFN-I production were found in the indigenous populations. The studies also reported a predominantly Th2-type response in these populations and a possibly higher susceptibility to tuberculosis. A better understanding of the relevant genetic polymorphisms and their role in immune regulation would help to clarify the immunogenetic mechanisms of TB infection in these populations. This information would be useful for identifying new treatments and preventing infection and progression to active disease.

Repercussão da adenotonsilectomia sobre o sistema imune a curto e longo prazo / Short and long term impact of adenotonsillectomy on the immune system

As tonsilas palatinas e faríngea são órgãos linfoides imunologicamente reativos, que manifestam anticorpos específicos e atividade de células B e T em resposta a uma variedade de antígenos, desempenhando funções de imunidade humoral e celular. Os possíveis efeitos imunológicos da adenotonsilectomia ainda permanecem controversos. OBJETIVO: O propósito desse estudo foi investigar o impacto da tonsilectomia na imunidade celular e humoral em crianças a curto e longo prazo. MÉTODO: Desenho do estudo: longitudinal prospectivo. Foram incluídas 29 crianças com indicação de adenotonsilectomia por hipertrofia adenoamigdaliana. IgA, IgM e IgG séricas e contagem de linfócitos foram analisados em 3 períodos: antes, 1 a 2 meses (curto prazo) e 12 a 14 meses (longo prazo) após o procedimento cirúrgico. RESULTADOS: Houve aumento estatisticamente significante de linfócitos TCD4+ a curto prazo após adenotonsilectomia. Os valores de IgA e IgG apresentaram diminuição significante a longo prazo, mas permaneceram dentro dos parâmetros de normalidade para a faixa etária. CONCLUSÃO: Os resultados do presente estudo indicam que a adenotonsilectomia, tanto a curto como a longo prazo, não apresenta repercussão negativa sobre a imunidade celular e humoral das crianças submetidas a este procedimento.

Palatine and pharyngeal tonsils are immune reactive lymphoid organs that manifest specific antibodies and B/T-cell activity to respond to a variety of antigens. They perform humoral and cellular immune functions. The possible effects of adenotonsillectomy upon the immune system remain controversial. OBJECTIVE: To study the short and long-term impacts of tonsillectomy upon the cellular and humoral immunity of children. METHOD: This longitudinal prospective study included 29 children referred to adenotonsillectomy for adenotonsillar hypertrophy. Serum IgA, IgM, and IgG and lymphocyte counts were analyzed at three points in time: before surgery, 1-2 months after surgery (short term), and 12-14 months after surgery (long term). RESULTS: TCD4+ cell counts were significantly increased shortly after surgery. IgA and IgG values were significantly reduced in the long run, but were within normal ranges for this age group. CONCLUSION: This study indicated that adenotonsillectomy does not pose negative short or long term impacts upon the cellular and humoral immunity of children submitted to the procedure.

Período de absorção intestinal de macromoléculas em cabritos recém-nascidos após a ingestão de colostro bovino / Macromolecules intestinal absorption period of goat kids after bovine colostrum intake

Após o nascimento, os cabritos são dependentes das imunoglobulinas colostrais devido às características placentárias que não permitem a passagem de macromoléculas da circulação materna. De acordo com a literatura, os cabritos possuem capacidade absortiva por até quatro dias. Muitos aspectos fisiológicos de outras espécies são aceitos e utilizados para caprinos, mas aqueles relacionados à transferência de imunidade passiva precisam de investigação. Os objetivos do presente estudo foram determinar o período de passagem de macromoléculas da mucosa intestinal para a circulação e a duração da proteção humoral transferida passivamente pela ingestão de colostro bovino e caprino. Sessenta cabritos recém-nascidos foram distribuídos em seis tratamentos: T 0 (n=25), ingestão natural de colostro caprino à vontade; T 1 (n=7), colostro bovino entre o nascimento e duas horas pós-parto; T 2 (n=7), ingestão de colostro bovino entre quatro e seis horas pós-nascimento; T 3 (n=7), leite nas primeiras oito horas e colostro bovino entre 10 e 12 horas pós-parto; T 4 (n=7), ingestão de leite até 18 horas e colostro bovino entre 22 e 24 horas pós-nascimento; T 5 (n=7), leite até 30 horas e ingestão de colostro bovino entre 34 e 36 horas pós-parto. Determinaram-se as concentrações séricas de proteína total (PT), gamaglobulina, imunoglobulina G (IgG) e a atividade sérica de gama glutamiltransferase (GGT). Ao nascimento, todos os neonatos tiveram valores mais baixos das variáveis, com aumento significativo da PT e gamaglobulina, após dois dias, nos grupos T 0, T 1 e T 2; a IgG e GGT aumentaram em todos os grupos. Os tratamentos T 3, T 4 e T 5 foram considerados como indutores de falha de transferência de imunidade passiva. A absorção de macromoléculas pelo trato intestinal dos cabritos ocorreu até 36 horas pós-parto, sendo mais efetiva até 12 horas. Os níveis de anticorpos persistiram até 75 dias após a ingestão de colostro bovino, porém, com concentrações inadequadas.

After birth goat kids are dependent of colostrum immunoglobulins due to placental characteristics that don't allow macromolecules passage from dam's circulation. According to literature goat kids have colostrum immunoglobulin absorption capability for up to four days. Many physiological aspects of other species have been accepted and used for goats, but those related to passive immunity transference needs more investigation. The goals of the present study was to determine the period of macromolecules passage through gut wall to circulation until 36 hours postpartum and verify the duration of protective humoral immunity transferred by the ingestion of bovine and caprine colostrum. Sixty newborn goat kids were allocated into six treatment groups: T 0 (n=25), non-restricted natural ingestion of goat colostrum; T 1 (n=7), bovine colostrum from birth to two hours postpartum; T 2 (n=7), bovine colostrum ingestion between four to six hours after birth; T 3 (n=7), milk intake until the first eight hours and bovine colostrum administration between 10 to 12 hours postpartum; T 4 (n=7), milk ingestion for the first 18 hours and bovine colostrum ingestion between 22 and 24 hours after birth; T 5 (n=7), milk administration until 30 hours and bovine colostrum intake between 34 to 36 hours postpartum. The total protein (TP), gammaglobulin, immunoglobulin G (IgG) and gamma-glutamyltransferase (GGT) serum concentrations were determined. At birth all neonates presented lower values of the variables, with significant increase of TP and gammaglobulin at two days in groups T 0, T 1 and T 2, IgG and GGT increased in all groups. The treatments T 3, T 4 and T 5 were considered to induce failure of immunity passive transfer. The absorption of macromolecules by kid's intestinal tract occurred until 36 hours postpartum, with better effectiveness until 12 hours. Antibody levels persist up to 75 days after bovine colostrum intake, but at this time their low concentrations doesn't provide adequate protection.

Carbohydrate-rich high-molecular-mass antigens are strongly recognized during experimental Histoplasma capsulatum infection / Antígenos de alta massa molecular ricos em carboidratos são fortemente reconhecidos durante infecção experimental por Histoplasma capsulatum

INTRODUCTION: During histoplasmosis, Histoplasma capsulatum soluble antigens (CFAg) can be naturally released by yeast cells. Because CFAg can be specifically targeted during infection, in the present study we investigated CFAg release in experimental murine histoplasmosis, and evaluated the host humoral immune response against high-molecular-mass antigens (hMMAg. >150 kDa), the more immunogenic CFAg fraction. METHODS: Mice were infected with 2.2x10(4) H. capsulatum IMT/HC128 yeast cells. The soluble CFAg, IgG anti-CFAg, IgG anti-hMMAg, and IgG-hMMAg circulating immune complexes (CIC) levels were determined by enzymelinked immunosorbent assay, at days 0, 7, 14, and 28 post-infection. RESULTS: We observed a progressive increase in circulating levels of CFAg, IgG anti-CFAg, IgG anti-hMMAg, and IgG-hMMAg CIC after H. capsulatum infection. The hMMAg showed a high percentage of carbohydrates and at least two main immunogenic components. CONCLUSIONS: We verified for the first time that hMMAg from H. capsulatum IMT/HC128 strain induce humoral immune response and lead to CIC formation during experimental histoplasmosis.

INTRODUÇÃO: Durante a histoplasmose, os antígenos solúveis de Histoplasma capsulatum (CFAg) podem ser liberados naturalmente pelas células leveduriformes. Considerando que os CFAg constituem um alvo específico durante a infecção, no presente estudo nós investigamos a liberação de CFAg durante a histoplasmose murina experimental, e avaliamos a resposta imune humoral do hospedeiro contra antígenos de alta MM (hMMAg; >150 kDa), altamente imunogênicos. MÉTODOS: Camundongos foram infectados com 2.2x10(4) leveduras de H. capsulatum, cepa IMT/HC128. Os níveis de CFAg solúveis, IgG anti-CFAg, IgG anti-hMMAg, e também de imunocomplexos circulantes (CIC) IgG-hMMAgs foram determinados por ELISA nos dias 0, 7, 14 e 28 após a infecção. RESULTADOS: Após a infecção por H. capsulatum, observamos um aumento progessivo de CFAg circulantes, IgG anti-CFAg, IgG anti-hMMAg, e também de CIC IgG-hMMAgs. Os hMMAg apresentaram alta porcentagem de carboidratos e, pelo menos, dois componentes imunogênicos. CONCLUSÕES: Mostramos pela primeira vez que os hMMAg de H. capsulatum cepa IMT/HC128 induzem resposta imune humoral e levam à formação de CIC durante a histoplasmose experimental.

Induction of humoral responses to BHV-1 glycoprotein D expressed by HSV-1 amplicon vectors

Herpes simplex virus type-1 (HSV-1) amplicon vectors are versatile and useful tools for transferring genes into cells that are capable of stimulating a specific immune response to their expressed antigens. In this work, two HSV-1-derived amplicon vectors were generated. One of these expressed the full-length glycoprotein D (gD) of bovine herpesvirus 1 while the second expressed the truncated form of gD (gDtr) which lacked the trans-membrane region. After evaluating gD expression in the infected cells, the ability of both vectors to induce a specific gD immune response was tested in BALB/c mice that were intramuscularly immunized. Specific serum antibody responses were detected in mice inoculated with both vectors, and the response against truncated gD was higher than the response against full-length gD. These results reinforce previous findings that HSV-1 amplicon vectors can potentially deliver antigens to animals and highlight the prospective use of these vectors for treating infectious bovine rhinotracheitis disease.

Introduction of the CIITA gene into tumor cells produces exosomes with enhanced anti-tumor effects

Exosomes are small membrane vesicles secreted from various types of cells. Tumor-derived exosomes contain MHC class I molecules and tumor-specific antigens, receiving attention as a potential cancer vaccine. For induction of efficient anti-tumor immunity, CD4+ helper T cells are required, which recognize appropriate MHC class II-peptide complexes. In this study, we have established an MHC class II molecule-expressing B16F1 murine melanoma cell line (B16F1-CIITA) by transduction of the CIITA (Class II transactivator) gene. Exosomes from B16-CII cells (CIITA-Exo) contained a high amount of MHC class II as well as a tumor antigen TRP2. When loaded on dendritic cells (DCs), CIITA-Exo induced the increased expression of MHC class II molecules and CD86 than the exosomes from the parental cells (Exo). In vitro assays using co-culture of immunized splenocytes and exosome-loaded DCs demonstrated that CIITA-Exo enhanced the splenocyte proliferation and IL-2 secretion. Consistently, compared to B16-Exo, CIITA-Exo induced the increased mRNA levels of inflammatory cytokines such as TNF-alpha, chemokine receptor CCR7 and the production of Th1-polarizing cytokine IL-12. A tumor preventive model showed that CIITA-Exo significantly inhibited tumor growth in a dose-dependent manner. Ex vivo assays using immunized mice demonstrated that CIITA-Exo induced a higher amount of Th1-polarized immune responses such as Th1-type IgG2a antibodies and IFN-gamma cytokine as well as TRP2-specific CD8+ T cells. A tumor therapeutic model delayed effects of tumor growth by CIITA-Exo. These findings indicate that CIITA-Exo are more efficient as compared to parental Exo to induce anti-tumor immune responses, suggesting a potential role of MHC class II-containing tumor exosomes as an efficient cancer vaccine.

Evaluation of the immune humoral response of Brazilian patients with Rubinstein-Taybi syndrome

Rubinstein-Taybi syndrome (RTS) is a rare developmental disorder characterized by craniofacial dysmorphisms, broad thumbs and toes, mental and growth deficiency, and recurrent respiratory infections. RTS has been associated with CREBBP gene mutations, but EP300 gene mutations have recently been reported in 6 individuals. In the present study, the humoral immune response in 16 RTS patients with recurrent respiratory infections of possible bacterial etiology was evaluated. No significant differences between patients and 16 healthy controls were detected to explain the high susceptibility to respiratory infections: normal or elevated serum immunoglobulin levels, normal salivary IgA levels, and a good antibody response to both polysaccharide and protein antigens were observed. However, most patients presented high serum IgM levels, a high number of total B cell and B subsets, and also high percentiles of apoptosis, suggesting that they could present B dysregulation. The CREBBP/p300 family gene is extremely important for B-cell regulation, and RTS may represent an interesting human model for studying the molecular mechanisms involved in B-cell development.

Clinical and immunological features of patients with atopy and concomitant HTLV-1 infection

Human T-cell lymphotropic virus type 1 (HTLV-1) induces an exacerbated type 1 immune response characterized by high spontaneous IFN-γ and TNF-α production. Allergic rhinitis and asthma are associated with the type 2 immune response, with elevated secretion of IL-4 and IL-5. The aim of this study was to characterize the immune response in atopic HTLV-1 carriers. The cytokine profile of atopic HTLV-1 carriers (N = 10; all females) was compared with that of non-atopic HTLV-1 carriers (N = 14; 9 females and 5 males). Mean patient age of atopic and non-atopic groups was 45 ± 8 and 38 ± 11 years, respectively. All atopic HTLV-1 carriers had rhinitis with or without asthma and a skin prick test positive for Dermatophagoides pteronyssinus antigen 1 (Derp-1). There was no difference in cytokine levels between the two groups in unstimulated peripheral blood mononuclear cell cultures. In cultures stimulated with Derp-1, IFN-γ levels tended to be higher (P = 0.06) and IL-5 levels were higher (P = 0.02) in atopic HTLV-1 patients than in non-atopic subjects. In contrast, IL-10 was lower (P = 0.004) in atopic than in non-atopic HTLV-1-infected subjects. This study shows that HTLV-1 infection with an exaggerated type 1 immune response does not prevent atopy. In this case, the exacerbated type 1 and type 2 immune responses were due to a lack of IL-10 production, a cytokine that plays an important role in down-modulating type 1 and type 2 immune responses and in preventing the development of chronic inflammatory diseases.

Humoral immune response of patients bitten by the snake Bothrops erythromelas / Resposta imune humoral em pacientes picados pela serpente Bothrops erythromelas

INTRODUCTION: Snake envenomings are a health problem in rural areas of tropical and subtropical countries, but little is known regarding the immune response presented by bitten individuals. The IgM production of patients bitten by Bothrops erythromelas snake was analyzed to identify the effectiveness of treatment in this type of envenomation. METHODS: Bothrops erythromelas venom was submitted to electrophoresis and transferred to a nitrocellulose sheet, following incubation with patients' sera. RESULTS: A 38 KDa protein was detected before and 24 h after therapy. CONCLUSIONS: The result suggests that this protein could be used as a marker for individuals envenomed by Bothrops. erythromelas.

INTRODUÇÃO: Envenenamentos ofídicos consistem problema de saúde pública em áreas rurais de países tropicais e subtropicais, mas pouco sabe-se sobre a resposta imune apresentada pelos indivíduos picados, por isso a avaliação da produção de IgM por pacientes picados por Bothrops erythromelas identificando a eficácia do tratamento nesse tipo de envenenamento. MÉTODOS: O veneno de Bothrops erythromelas foi submetido a eletroforese e transferido para nitrocelulose, seguindo incubação com soro de pacientes. RESULTADOS: Foi observada proteína de 38KDa antes e 24 horas após o tratamento. CONCLUSÕES: Os resultados sugerem que essa proteína poderia ser utilizada como marcador para indivíduos envenenados pela serpente Bothrops erythromelas.

Green propolis phenolic compounds act as vaccine adjuvants, improving humoral and cellular responses in mice inoculated with inactivated vaccines

Adjuvants play an important role in vaccine formulations by increasing their immunogenicity. In this study, the phenolic compound-rich J fraction (JFR) of a Brazilian green propolis methanolic extract stimulated cellular and humoral immune responses when co-administered with an inactivated vaccine against swine herpesvirus type 1 (SuHV-1). When compared to control vaccines that used aluminium hydroxide as an adjuvant, the use of 10 mg/dose of JFR significantly increased (p < 0.05) neutralizing antibody titres against SuHV-1, as well as the percentage of protected animals following SuHV-1 challenge (p < 0.01). Furthermore, addition of phenolic compounds potentiated the performance of the control vaccine, leading to increased cellular and humoral immune responses and enhanced protection of animals after SuHV-1 challenge (p < 0.05). Prenylated compounds such as Artepillin C that are found in large quantities in JFR are likely to be the substances that are responsible for the adjuvant activity.