Prokaryotic expression of a recombinant protein of adeno-associated virus capsid conserved regions and preparation of its polyclonal antibody / 南方医科大学学报

OBJECTIVE@#To express and purify the antigenic peptide of adeno-associated virus (AAV) capsid conserved regions in prokaryotic cells and prepare its rabbit polyclonal antibody.@*METHODS@#The DNA sequence encoding the conserved regions of AAV capsid protein was synthesized and cloned into the vector pET30a to obtain the plasmid pET30a-AAV-CR for prokaryotic expression and purification of the conserved peptides. Coomassie blue staining and Western blotting were used to identify the AAV conserved peptides. Japanese big ear white rabbits were immunized with AAV conserved region protein to prepare polyclonal antibody, with the rabbits injected with PBS as the control group. The antibody titer was determined with ELISA, and the performance of the antibody for recognizing capsid protein sequences of AAV1-AAV10 was assessed with Western blotting and immunofluorescence assay.@*RESULTS@#The plasmid pET30a-AAV-CR was successfully constructed, and a recombinant protein with a relative molecular mass of 17000 was obtained. The purified protein induced the production of antibodies against the conserved regions of AAV capsid in rabbits, and the titer of the purified antibodies reached 1:320 000. The antibodies were capable of recognizing a wide range of capsid protein sequences of AAV1-AAV10.@*CONCLUSION@#We successfully obtained the polyclonal antibodies against AAV capsid conserved region protein from rabbits, which facilitate future studies of AAV vector development and the biological functions of AAV.

Identificación de una triparedoxina peroxidasa citoplasmática en Leishmania braziliensis / Identification of a cytoplasmic tryparedoxin peroxidase from Leishmania braziliensis / Identificação de uma triparedoxina peroxidase citoplasmica de Leishmania braziliensis

Resumen Los sistemas de defensa anti-oxidante utilizados por el parásito intracelular Leishmania braziliensis durante el proceso de infección permiten eliminar especies reactivas de oxígeno y nitrógeno a expensas de equivalentes reductores derivados de la tripanotiona, evitando daños celulares del patógeno. Con el objetivo de identificar potenciales blancos moleculares para el desarrollo de fármacos contra este parásito, se realizó la detección de la enzima triparedoxina peroxidasa citoplasmática de L. braziliensis (LbTXNPxII), la cual es esencial para disminuir concentraciones tóxicas de peróxido de hidrógeno en el contexto de infección. Para esto se generaron anticuerpos policlonales en modelo aviar, partiendo de la clonación, expresión y purificación de la proteína recombinante 6xHis-SUMO-LbTXNPxII (37kDa) en el sistema heterólogo Escherichia coli. La proteína purificada se utilizó como antígeno para la producción de anticuerpos IgY, cuya implementación en estudios in situ permitió detectar y localizar la enzima LbTXNPxII endógena (22kDa) en el citoplasma de promastigotes fijados y verificar su interacción molecular con la nicotinamida/ nicotinato mononucleótido adenilil transferasa, enzima involucrada en la síntesis del NAD. De este modo, se reporta el desarrollo de una herramienta bioquímica para la identificación y estudio de la enzima LbTXNPxII y su participación en vías del metabolismo energético y de defensa anti-oxidante.

Abstract The antioxidant defense systems used by the intracellular parasite Leishmania braziliensis during the infection process make it possible to eliminate reactive oxygen and nitrogen species at the expense of reducing equivalents derived from trypanothione, avoiding cellular damage of the pathogen. In order to identify potential molecular targets for the development of drugs against this parasite, the cytoplasmic tryparedoxin peroxidase of L. braziliensis (LbTXNPxII), which is essential to reduce toxic concentrations of hydrogen peroxide in the context of infection, was carried out. In this regard, polyclonal antibodies were generated in an avian model, starting from the cloning, expression, and purification of the recombinant protein 6xHis-SUMO-LbTXNPxII (37kDa) in the heterologous system of Escherichia coli. The purified protein was used as an antigen for the production of IgY antibodies, whose implementation in in situ experiments allowed the detection and localization of the endogenous LbTXNPxII enzyme (22kDa) in the cytoplasm of fixed promastigotes, as well as the verification of its molecular interaction with nicotinamide/nicotinate mononucleotide adenylyltransferase, an enzyme involved in the synthesis of NAD. Thus, the development of a biochemical tool for the identification and study of the LbTXNPxII enzyme and its participation in energy metabolism and antioxidant defense pathways is reported.

Resumo Os sistemas de defesa antioxidante utilizados pelo parasita intracelular Leishmania braziliensis durante o processo de infecção, permitem a eliminação de espécies reativas de oxigênio e nitrogênio em detrimento de equivalentes redutores derivados de tripanotiona, evitando o dano celular do patógeno. Com o objetivo de identificar potenciais alvos moleculares para o desenvolvimento de drogas contra esse parasita, foi detectada a enzima citoplasmática triparedoxina peroxidase de L. braziliensis (LbTXNPxII), essencial para reduzir as concentrações tóxicas de peróxido de hidrogênio no contexto de infecção. Para isso, anticorpos policlonais foram gerados em modelo aviário, a partir da clonagem, expressão e purificação da proteína recombinante 6xHis-SUMO-LbTXNPxII (37kDa) no sistema heterólogo de Escherichia coli. A proteína purificada foi utilizada como antígeno para a produção de anticorpos IgY, cuja implementação em experimentos in situ permitiu a detecção e localização da enzima LbTXNPxII endógena (22kDa) no citoplasma de promastigotas fixos e verificar sua interação molecular com nicotinamida/nicotinato mononucleotídeo adenililtransferase, enzima envolvida na síntese de NAD. Assim, é relatado o desenvolvimento de uma ferramenta bioquímica para a identificação e estudo da enzima LbTXNPxII e sua participação no metabolismo energético e nas vias de defesa antioxidante.

Development and characterization of polyclonal antibodies against the linker region of the telomere-binding protein TRF2

Background: TRF2 (telomeric repeat binding factor 2) is an essential component of the telomere-binding protein complex shelterin. TRF2 induces the formation of a special structure of telomeric DNA and counteracts activation of DNA damage-response pathways telomeres. TRF2 has a poorly characterized linker region (udTRF2) between its homodimerization and DNA-binding domains. Some lines of evidence have shown that this region could be involved in TRF2 interaction with nuclear lamina. Results: In this study, the fragment of the TERF2 gene encoding udTRF2 domain of telomere-binding protein TRF2 was produced by PCR and cloned into the pET32a vector. The resulting plasmid pET32a-udTRF2 was used for the expression of the recombinant udTRF2 in E. coli RosettaBlue (DE3). The protein was isolated and purified using ammonium sulfate precipitation followed by ion-exchange chromatography. The purified recombinant protein udTRF2 was injected into guinea pigs to generate polyclonal antibodies. The ability of anti-udTRF2 antibodies to bind endogenous TRF2 in human skin fibroblasts was tested by western blotting and immunofluorescent staining. Conclusions: In this study, the recombinant protein udTRF2 and antibodies to it were generated. Both protein and antibodies will provide a useful tool for investigation of the functions of the udTRF2 domain and its role in the interaction between TRF2 and nuclear lamina.

Preparation and identification of polyclonal antibodies against Moraxella catarrhalis UspA1 / 生物工程学报

To prepare polyclonal antibodies (PcAb) against UspA1 of Moraxella catarrhalis (Mc), we used bioinformatic analysis to determine the surface exposed region in this protein that holds the antigen epitopes. Then the corresponding coding sequences for this fragment was artificially synthesized according to the codon usage of Escherichia coli. The gene fragment was then subcloned into the prokaryotic expression vector pET-28a(+) and expressed in E. coli rosseta (DE3), and then the recombinant UspA1-His proteins were purified. Two New Zealand white rabbits were immunized with this protein to prepare antiserum. The resulting PcAb was then purified from the antiserum with Protein A affinity column. The results of fluorescence antibody assay, enzyme linked immunosorbent assay and Western blotting analysis showed that the PcAb could specifically recognize the surface exposed region of UspA1 on Mc. The preparation of the PcAb laid a foundation of further development of rapid detection technique for M. catarrhalis.

Nicotinamide mononucleotide adenylyltransferase of Trypanosoma cruzi (TcNMNAT): a cytosol protein target for serine kinases

Nicotinamide/nicotinate adenine dinucleotide (NAD+/NaAD) performs essential functions in cell metabolism and energy production due to its redox properties. The nicotinamide/nicotinate mononucleotide adenylyltransferase (NMNAT, EC 2.7.7.1/18) enzyme catalyses the key step in the biosynthesis of NAD+. Previously, the enzyme NMNAT was identified in Trypanosoma cruzi (TcNMNAT), a pathogenic agent with epidemiological importance in Latin America. To continue with the functional characterisation of this enzyme, its subcellular location and its possible post-translational modifications were examined in this study. For this, polyclonal antibodies were generated in mice, with soluble and denatured recombinant protein being used to detect the parasite’s NMNAT. Immunodetection assays were performed on whole extracts of T. cruzi, and an approximation of its intracellular location was determined using confocal microscopy on wild and transgenic parasites, which revealed the cytosol distribution patterns. This localisation occurs according to the needs of the dinucleotides that exist in this compartment. Additionally, a bioinformatics study was performed as a first approach to establish the post-translational modifications of the enzyme. Possible phosphorylation events were experimentally analysed by western blot, highlighting TcNMNAT as a potential target for serine kinases.

Characterization of an IgM-like immunoglobulin from silver catfish (Rhamdia quelen) serum and its use for the production of polyclonal antibodies and development of immunoassays / Caracterização de imunoglobulina similar a IgM em soros de jundiás (Rhamdia quelen) e sua utilização para a produção de soro policlonal e desenvolvimento de imunoensaios

Knowledge on fish immunoglobulin (Ig) characteristics and the availability of monoclonal or polyclonal antibodies to fish Igs are essential to evaluate the humoral immune response and the Ig distribution on leukocyte cells. We demonstrated that silver catfish serum Ig is composed of one immunodominant H chain with approximately 75k Da and one L chain with approximately 28 kDa, similar to human IgM. Rabbit polyclonal antibodies to the catfish IgM-like Ig recognized both the H and L chain and were useful in developing an indirect ELISA to measure the production of antibodies in fish immunized with bovine serum albumin. Dot blot and western blot cross-reactivity studies indicated a wide degree of epitope sharing amongst Ig from several Siluriformes and Characiformes fish indigenous to Brazilian rivers. In these fish species, polyclonal antibodies reacted mostly with the H chain. The results presented here are central to the development of tools and strategies to investigate the antibody production to inoculated antigens and tissue distribution of Ig molecules in native fish species. Furthermore, because of the wide range of cross-reactivity, polyclonal antibodies to silver catfish IgM-like Ig might be used to develop immunoassays to measure the humoral immune response in other fish species.(AU)

Informações sobre as características das imunoglobulinas (Ig) de peixes e a disponibilidade de anticorpos mono ou policlonais são essenciais para avaliar a resposta imune humoral e a distribuição leucocitária de Igs. Nesse trabalho nós demonstramos que a Ig do soro de jundiás é composta por uma cadeia pesada (H) imunodominante, de aproximadamente 75kDA e de uma cadeia leve (L) de aproximadamente 28 kDa, similar à IgM humana. Anticorpos policlonais produzidos contra a Ig do jundiá reconheceram a cadeia H e L e permitiram o desenvolvimento de um ELISA indireto para mensurar a produção de anticorpos em peixes imunizados com albumina sérica bovina. Estudos de reatividade cruzada, por meio de Dot blot e western blot, indicaram um alto grau de compartilhamento de epitopos entre as Igs de diversos peixes Siluriformes e Caraciformes nativos do Brazil. Nestas espécies de peixes, os anticorpos policlonais reconheceram principalmente a cadeia H. Os resultados deste estudo são fundamentais para o desenvolvimento de ferramentas e estratégias para investigar a produção de anticorpos subsequente à imunização e a distribuição tecidual de Igs em peixes nativos. Além disso, devido ao compartilhamento de epitopos entre as espécies de peixes avaliadas, os anticorpos policlonais anti Ig do jundiá poderão ser usados para desenvolver ensaios imunoenzimáticos para avaliar a resposta imune humoral nestas espécies.(AU)

Evaluation of Direct Rapid Immunohistochemical test (DRIT) of Canis lupus familiaris hippocampal touch impression smears using a monospecific polyclonal antibody for rabies virus detection

@#<p style="text-align: justify;"><strong>BACKGROUND:</strong> Rabies is an important zoonotic disease that needs to be eradicated worldwide. It is still prevalent in the Philippines, thus development of a relatively affordable but still accurate and rapid post-mortem detection test for the virus is desired, especially in regional laboratories.<br /><strong>METHODS:</strong>The study evaluated the Direct Rapid Immunohistochemical Testing (DRIT) of hippocampal touch impressions of suspected rabid Canis lupus familiaris using monospecific N protein polyclonal antibody developed by the Research Institute for Tropical Medicine (RITM). One hundred sixty (160) acetone-fixed hippocampal touch impressions were subjected DRIT.<br /><strong>RESULTS:</strong> One hundred thirteen (70.6%) out of 160 samples tested positive for rabies viral antigen (RVA) and 47 (29.4%) out of 160 samples tested negative for RVA. No false positive and false negative results were obtained. The results agree with the gold standard, dFAT.<br /><strong>CONCLUSION:</strong> DRIT was able to detect low to high concentrations of RVA in the hippocampal touch impressions based on the grading distribution. DRIT had 100% sensitivity, specificity and over-all accuracy using monospecific polyclonal antibodies, which suggests its use as a more affordable alternative to the gold standard dFAT.</p>

Prokaryotic expression, polyclonal antibody preparation and immunoprotection potential of Pseudomonas aeruginosa outer membrane protein OprH / 第二军医大学学报

Objective To lay a foundation for the industrial fermentation and vaccine development of Pseudomonas aeruginosa (P. oeruginosa) outer membrane protein OprH. Methods The OprH expression strain was obtained by molecular cloning. The culture condition and optimal expression of the experiment was obtained by the method of orthogonal design. OprH was purified by gel slice strategy and was used to immunize mice to prepare the polyclonal antibody. The antibody titer and specificity were detected by ELISA and Western blotting analysis, respectively. Mice were immunized by OprH protein and infected with P. aeruginosa, and the immune protection of OprH was detected. Results OprH recombinant vector were digested and sequenced, and the results confirmed the correct construction; and OprH expression and purification of strip size agreed with the prediction. The optimal culture condition was as follows: rotation rate was 230 r/min, glucose concentration was 0%, and the medium volume was 50 mL. The optimal inducing expression condition of OprH was as follows: isopropy-β-D-thiogalactoside final concentration was 0.3 mmol/L, strain D600 value was 0.8, inducing temperature was 32℃, and inducing time was 3 h. The OprH antibody titer was 1:1 600 as detected by ELISA, and Western blotting analysis proved that the antiserum had good specificity. Mice specific immune was activated by OprH, and immune protection rate for mice against P. aeruginosa infection was 46.15 %, which had significant differences compared with the control (P<0.05). Conclusion We have successfully cloned OprH expression vector, purified OprH, prepared the polyclonal antibodies of OprH. It is confirmed that OprH protein has significant immune protection against P. aeruginosa, and the culture and induction conditions of the recombinant OprH have been obtained.

Production and Characterization of IgY against Canine IgG: Prospect of a New Tool for the Immunodiagnostic of Canine Diseases

This study describes the production of a new avian polyclonal antibody (IgY) against canine IgG, as another tool for the immunodiagnostic using IgY technology. The immunization protocol caused neither deaths nor pathologies, and no decline in egg laying capacity was detected. The total concentration of isolated IgY was constant, without significant difference (p> 0.05), with average of 97.55 mg of IgY/yolk. The IgY revealed a strong sensitivity and specificity in recognition against canine IgG by ELISA. After the immunization, there was a significant increase in the production of IgY specific from the first to the second month (p <0.05), reaching a stable peak without decrease in the production by the end of the analysis period (p > 0.05). The IgY demonstrated a suitable specificity in Western blot against the purified and serum canine IgG, not enabling recognition of canine IgM or IgG of other animal species. The specific IgY in the egg yolks of immunized hens proved to be a molecule with an appropriate purity and desired specificity against the immunizing antigen. Moreover, its constant production in large quantities during the four months analyzed indicated that IgY antibody production technology could be considered as an excellent alternative to the standard methods.

Avian IgY antibodies: characteristics and applications in immunodiagnostic / Anticorpos IgY aviário: características e aplicações em imunodiagnóstico

Immunoglobulin Y (IgY) is the major antibody isotype in birds, reptiles, amphibia, and lungfish, playing a similar biological role as mammal IgG. Due to its phylogenetic distance, immune diversification and presence in the egg yolk, IgY provide a number of advantages in immunodiagnostic compared to IgG from mammals. Moreover, IgY production is in agreement with international efforts to reduce, refine and if possible, to replace animals in experimentation, contributing substantially in favor of animal welfare. This article presents an overview about structural and functional features, production and applications of IgY in immunodiagnostic, as well as the advantages of chicken antibodies use.

A imunoglobulina Y (IgY) é a classe de anticorpos de maior importância em aves, répteis, anfíbios e peixes pulmonados, desempenhando um papel semelhante a IgG de mamíferos. Devido a sua distância filogenética, mecanismos de diversificação imune e presença na gema do ovo, IgY proporciona uma série de vantagens em imunodiagnóstico, quando comparada a IgG de mamíferos. Além disso, esse método alternativo de produção de anticorpo está de acordo com os esforços internacionais para reduzir, refinar e, se possível, substituir animais em experimentação, contribuindo substancialmente a favor do bem-estar animal. Este artigo apresenta uma revisão sobre as características estruturais e funcionais da IgY, bem como os métodos de produção, vantagens e aplicações em imunodiagnóstico, além das vantagens da sua utilização.

Production of anti-Cryptosporidium polyclonal antibodies and standardization of direct immunofluorescence for detecting oocysts in water / Produção de anticorpos policlonais anti-Cryptosporidium e padronização da imunofluorescência direta para a detecção de oocistos na água

INTRODUCTION: The production of anti-Cryptosporidium polyclonal antibodies and its use in direct immunofluorescence assays to determine the presence of Cryptosporidium in water are described in the present work. METHODS: Two rabbits were immunized with soluble and particulate antigens from purified Cryptosporidium oocysts. The sera produced were prepared for immunoglobulin G extraction, which were then purified and conjugated with fluorescein isothiocyanate (FITC). Slides containing known amounts of oocysts were prepared to determine the sensitivity of the technique. To test the specificity, slides containing Giardia duodenalis cysts were prepared. RESULTS: The conjugate was successfully used in water samples experimentally contaminated with Cryptosporidium oocysts, and it was possible to detect up to five oocysts/spot, corresponding to contamination of 250 oocysts/mL. CONCLUSIONS: The three immunizations performed in the rabbits were enough to produce antibodies against Cryptosporidium, the standard direct immunofluorescence assay permitted the detection of five oocysts in 20 percent of the samples, and no cross-reaction with Giardia duodenalis cysts occurred.

INTRODUÇÃO: A produção de anticorpos policlonais anti-Cryptosporidium e sua utilização na imunofluorescência para determinar a presença de Cryptosporidium em água são descritas no presente trabalho. MÉTODOS: Dois coelhos foram imunizados com antígeno solúvel e particulado provenientes de oocistos purificados de Cryptosporidium. O soro produzido foi preparado para a extração de imunoglobulinas G, que foram purificadas e conjugadas com isotiocianato de fluoresceína (FITC). Lâminas contendo quantidades conhecidas de oocistos foram preparadas para determinar a sensibilidade da técnica. Para testar a especificidade foram preparadas lâminas contendo cistos de Giardia duodenalis. RESULTADOS: O conjugado foi usado com sucesso em amostras de água contaminadas experimentalmente com oocistos de Cryptosporidium, sendo capaz de detectar até cinco oocistos/spots que corresponde a uma contaminação de 250 oocistos/mL. CONCLUSÕES: As três imunizações realizadas nos coelhos foram suficientes para produção de anticorpos contra Cryptosporidium; a reação de imunofluorescência direta padronizada permitiu a detecção de cinco oocistos em 20 por cento das amostras; não houve reação cruzada com cistos de Giardia duodenalis.

Generation and preliminary application of polyclonal antibodies against human Argonaute2 / 中国免疫学杂志

Objective:To generate rabbit polyclonal antibody against human Argonaute2 (Ago2) protein and to identify its functional characterization for determination of differential expression and cellular localization of Ago2 protein in various cell lines.Methods:DNAstar software was applied for searching the high antigenicity region of Ago2 gene sequence termed k-Ago2.Prokaryotic expressing plasmid was constructed and transformed to E.coli BL21 (DE3) to induce expression by IPTG.The fusion protein was injected into rabbits subcutaneously to produce polyclonal antibodies after purification by gel regaining.ELISA was operated to detect antibody titer.Western blot was used to identify the specificity and sensitivity of the antibodies and detect the differential expression of Ago2 protein in various cell lines.Meanwhile,immunofluorescence experiments were arranged to show cellular localization of Ago2 protein.Results:The prokaryotic expressing plasmid was constructed correctly.K-Ago2 protein was expressed and purified,and then rabbit polyclonal antibodies against Ago2 were generated after immunization with k-Ago2 protein.The titer detected by ELISA was 1∶19 000.Western blot results demonstrated the high specificity of the antibodies.Finally,we successfully observed the differential expression and cellular localization of Ago2 protein in various cell lines.Conclusion:The polyclonal antibody against Ago2 protein has been achieved successfully.It will be propitious for the intensive study of the RNAi mechanism and even profound clinical application.

Preparation and application of antibodies against advanced oxidation protein products / 中国免疫学杂志

Objective:To prepare the polyclonal antibodies against advanced oxidation protein products (AOPP),and to provide an effective agent for research on the pathogenesis of AOPP and assess exactly the relationship between AOPP and relative diseases.Methods:AOPP-rabbit serum albumin (AOPP-RSA) was prepared by treating RSA with hypochloric acid.The rabbit anti-AOPP-RSA polyclonal antibodies were generated and purified by affinity chromatography. The titers and the specificity of the antibodies were measured by ELISA.The plasma AOPP and the localization of AOPP in nephridial tissues of some patients with chronic kidney disease (CKD) were determined using rabbit anti-AOPP-RSA.Results:Titers of the antibodies were 10-6.Purified antibodies reacted specifically with oxidized albumin from different genus,but could not react with normal albumin and glycosylated albumin.The high level of AOPP in plasma from CKD patients was confirmed by Western blot.The antibodies could be used to immunostain AOPP deposition in different regions of kidney tissues from both CKD patients and CKD rat models.Conclusion:We successfully generate rabbit anti-AOPP polyclonal antibodies with high titers and striking specificity.The presence of plasma AOPP and localizations of AOPP in kidney tissues of CKD patients can be demonstrated using the antibodies.The development of anti-AOPP polyclonal antibodies may provide a new tool to explore the pathogensis of AOPP and assess exactly the relationship between AOPP and relative diseases.

Prokaryotic Expression and Potential Application of the Truncated PCV-2 Capsid Protein / 中国病毒学·英文版

Three pairs of specific primers were designed to amplify the F2-1, F2-2 and XF2-2 truncated sequences of ORF2 which encodes the capsid protein of porcine circovirus type 2 (PCV-2). The F2-1 sequence had most of the NLS region of ORF2, but the F2-2 and XF2-2 genes had the NLS region deleted. Truncated genes were subcloned into pET-32a(+) vectors to construct recombinant fusion expression vectors. The vectors were then transformed into Rosetta(DE3) E. coli and expressed by induction of IPTG. Expressed proteins were detected by western blotting and ELISA. The protein with best immunoreactivity was confirmed and selected, then utilized to inoculate SPF rabbits to prepare polyclonal antibodies. The protein and prepared polyclonal antibody were utilized to detect sera samples against PCV-2 from Shandong province and PCV-2 particles in PK-15 cells. In our study, three recombinant fusion proteins were successfully obtained, and the molecular weights of fusion proteins were 35.9 kDa, 33.6 kDa and 38.6 kDa respectively detected by SDS-PAGE. All of the proteins showed positive reaction with anti-PCV-2 antisera, and His-XF2-2 showed better immunoreactivity than the others. The protein of His-XF2-2 was coated as antigen in ELISA to detect the seroprevalence of PCV-2 in certain districts of Shandong province, the seropositivity rate was 27.7 % (73/264). Specific fluorescence and positive signals for PCV-2 could be detected in PK-15 cells inoculated with PCV-2 with the participation of prepared antibodies against His-XF2-2 in IFA and IPMA. Experimental results indicated that the truncated PCV-2 ORF2 gene containing most of the NLS region was successfully expressed in E. coli, and His-XF2-2 was demonstrated to have better immunoreactivity with anti-PCV-2 antisera than the other two fusion proteins. His-XF2-2 and prepared polyclonal antibodies against it had a satisfactory capability in detecting PCV-2 infection.

Desensibilización y trasplante renal: plasmaféresis-IVIG a dosis estándar en pacientes con alto riesgo inmunológico / Desensitization and renal transplant: plasmapheresis/IVIG standard dose in patients with high immunological risk

Introducción: Los pacientes con alto riesgo inmunológico siguen siendo relegados a la cada vez más larga lista de espera de un donador inmunológicamente compatible. El objetivo de esta comunicación es informar la experiencia de un centro de trasplantes en la desensibilización de pacientes con alto riesgo inmunológico. Material y métodos: Estudio descriptivo y retrospectivo de todos los pacientes sometidos a trasplante renal de noviembre de 1999 a enero de 2008, en quienes se llevó a cabo desensibilización pretrasplante renal. Resultados: Ocho pacientes presentaron aloinmunización (pruebas cruzadas positivas o panel reactivo de anticuerpos alto, PRA > 30 %). La desensibilización se realizó mediante sesiones de plasmaféresis con recambio de 1.5 volúmenes plasmáticos, y posterior a cada una se administró una dosis estándar de inmunoglubulina intravenosa (IVIG 5 g/dosis). La inmunosupresión se inició en la primera sesión de plasmaféresis con base en un inhibidor de calcineurinas (tacrolimus); en seis pacientes se añadió mofetil micofenolato y en dos, sirolimus. En siete se obtuvieron pruebas cruzadas negativas con el donador previo al trasplante; en el octavo no se efectuaron. En dos se administró anticuerpos humanizados contra CD25 (20 mg/dosis de basiliximab). Todos los pacientes han mantenido función estable del injerto. Conclusiones: De acuerdo con nuestra experiencia, la sobrevida del injerto renal en pacientes con alto riesgo inmunológico posterior a un adecuado protocolo de desensibilización y estrecha vigilancia postrasplante es similar a la observada en pacientes no sensibilizados, al menos durante el primer año del trasplante.

BACKGROUND: Patients with high immunological risk have been relegated to the growing waiting list for an immunologically compatible donor. Our objective was to report the experience of a transplant center in desensitization of patients with high immunological risk. METHODS: We carried out a descriptive and retrospective study. Included were all the renal transplant patients from November 1999 to January 2008 in which we used plasmapheresis and standard dose of intravenous immunoglobulin (IVIG) as desensitization. RESULTS: Eight patients had history of alloimmunity (positive crossmatch or high panel-reactive antibodies (PRA >30%). Desensitization was accomplished with plasmapheresis and exchange of 1.5 plasma volume. Subsequent to each session we administered a standard dose of IVIG (5 g/dose). Immunosuppression began equal to the first plasmapheresis with calcineurin inhibitor (tacrolimus) plus six patients with mycophenolate mofetil and two patients with sirolimus. In seven cases, negative crossmatches were obtained before the transplantation, except in the eighth case in whom it was not done. Two patients received human antibodies against CD25 (basiliximab, 20 mg/dose). During their evolution, all patients maintained stable graft function. CONCLUSIONS: According to our experience, renal graft outcome in patients with high immunological risk after an adequate desensitization protocol is similar to that observed in nonsensitized patients, at least during the first year of transplantation.

Superioridad del uso de anticuerpos policlonales (Thymogam) en pacientes con trasplantes renales en el Instituto de Nefrología, 2003-2007 / Use superiority of polyclonal antibodies (Thymogan) in patients underwent to renal transplants in Nephrology Institute, 2003-2007

Introducción: Estudio observacional descriptivo de cohorte retrospectiva, para comparar la incidencia de rechazo agudo (RA), su clasificación (Banft 1997) y las causas de pérdidas de los injertos, entre 3 protocolos de inmunosupresión. Métodos: Se estudiaron todos los trasplantes renales, donante cadáver (116), realizados en el Instituto de Nefrología "Dr. Abelardo Buch López", entre los años 2003 y 2007. Se excluyeron los pacientes que perdieron la función renal o fallecieron por causas ajenas al protocolo inmunosupresor empleado. Los protocolos comparados fueron: I. Cuádruple secuencial con anticuerpos policlonales (AcP, Thymogam), II. Cuádruple secuencial con anticuerpos monoclonales (AcM, IOR-T3) y III. Triple. Se analizaron variables inmunológicas como compatibilidad HLA y porcentaje de anticuerpos anti HLA y no inmunológicas, como número de TR, edad del donante, causa de muerte, isquemia fría, necrosis tubular aguda pos TR, días de tratamiento con las terapias biológicas y reacciones colaterales. Se utilizó la distribución de frecuencias y el test de homogeneidad, en el análisis de las variables cualitativas. En las cuantitativas se calculó media aritmética y desviación estándar y se empleó el test de Kruskal Wallis. Resultados: El protocolo I evidenció menor incidencia de la primera crisis de RA (18,5 vs. 33,3 y 43,2 % para los protocolos II y III), sin pérdidas de injertos por RA en el primer año, pese haber sido utilizado en pacientes con mayor riesgo inmunológico, a diferencia de los protocolos II y III donde sí se encontraron pérdidas de los trasplantes en el 22,2 y 20,5 %, respectivamente. Cuando se presentó el RA, la severidad fue mucho menor en el protocolo I (25,0 % sospechoso de RA y 75,0 % RA IA) a diferencia de los RA en los protocolos II y III donde también existió RA IIA y IIB. Conclusiones: El protocolo cuádruple secuencial con AcP, Thymogam, tiene mejores resultados en nuestro medio y es ideal en pacientes de mayor riesgo inmunológico.

Introduction: It is a descriptive and observational and retrospective study to compare acute rejection incidence (AR), its classification (Banft 1997), and causes of grafts lost among three immunosuppression protocols. Methods: Cadaver donor renal transplants (116) were studied in "Dr. Abelardo Buch López" Nephrology Institute from 2003 to 2007. Were excluded those patients with loss of renal function or deceased from causes other than immunosuppression protocol used. Protocols compared were: I. Quadruple sequential with polyclonal antibodies (AcP, Thymogam). II. Quadruple sequential with monoclonal antibodies (AcM, IOR-T3), and III. Triple. Immunological variables analyzed were: HLA compatibility and percentage of anti-HLA antibodies and no-immunologic ones, as TR number, donor' age, death cause, cold ischemia, post-TR acute tubular necrosis, treatment extent (days) using biological therapies and collateral reactions. We used the frequency distribution and homogeneity test in qualitative variables analysis. In the quantitative ones SD and arithmetic mean were estimated and Kruskal Wallis test was used. Results: I protocol evidenced a lower incidence of the first RA crisis during the 1st year in spite of its use in patients with a great immunologic risk, unlike II and III protocols, where there were transplant losses in 22,2 % and 20,5%, respectively. When RA was present, severity was very lower in I protocol (25,0% suspected of RA and 75,0% RA IA) unlike the RAs in II and III protocols where also were RA IIA and IIb. Conclusions: Sequential quadruple protocol with AcP, Thymogan, has better results in our practice and it is ideal in patients with a mayor immunologic risk.

Heterologous expression and biochemical characterization of an alpha 1, 2-mannosidase encoded by the Candida albicans MNS1 gene

Protein glycosylation pathways, commonly found in fungal pathogens, offer an attractive new area of study for the discovery of antifungal targets. In particular, these post-translational modifications are required for virulence and proper cell wall assembly in Candida albicans, an opportunistic human pathogen. The C. albicans MNS1 gene is predicted to encode a member of the glycosyl hydrolase family 47, with 1,2-mannosidase activity. In order to characterise its activity, we first cloned the C. albicans MNS1 gene into Escherichia coli, then expressed and purified the enzyme. The recombinant Mns1 was capable of converting a Man9GlcNAc2 N-glycan core into Man8GlcNAc2 isomer B, but failed to process a Man5GlcNAc2-Asn N-oligosaccharide. These properties are similar to those displayed by Mns1 purified from C. albicansmembranes and strongly suggest that the enzyme is an ±1,2-mannosidase that is localised to the endoplasmic reticulum and involved in the processing of N-linked mannans. Polyclonal antibodies specifically raised against recombinant Mns1 also immunoreacted with the soluble ±1,2-mannosidases E-I and E-II, indicating that Mns1 could share structural similarities with both soluble enzymes. Due to the high degree of similarity between the members of family 47, it is conceivable that these antibodies may recognise ±1,2-mannosidases in other biological systems as well.

Preparation of Monospecific Polyclonal Antibodies Against Glechoma hederacea Agglutinin / 生物化学与生物物理进展

Glechoma hederocea agglutinin (Gleheda) is a novel glycosylated lectin isolated from the leaves of G. hederacea. Like other glycosylated proteins, the detection of Gleheda by immunological methods is often hampered by the cross-reactivity of the polyclonal antibodies with unrelated glycoproteins. Hence a protocol to purify monospecific polyclonal antibodies from a crude antiserum raised against Gleheda was developed. After selective ammonium sulfate precipitation and successive affinity chromatography on columns of Sepharose 4B with immobilized Gleheda and Robinia pseudoacacia agglutinin (RPA), respectively, ion-exchange chromatography on a column of Q Fast Flow was used for further purification. The specificity of the antibody fractions from each step was tested by double immunodiffusion assay and analyzed by Western blot. Results revealed that affinity chromatography of the immunoglobulin fraction on the immobilized Gleheda antigen yielded an antibody preparation that still cross-reacted with many proteins in leaf extracts. Depletion of nonspecific cross-reacting antibodies directed against the glycan part of the glycoprotein by affinity chromatography on immobilized RPA removed most but not all nonspecifically reacting antibodies. Only upon further purification by ion exchange chromatography an IgG fraction of monospecific antibodies that reacted exclusively with Gleheda could be obtained and accordingly was suitable for immunodetection studies. This antibody purification procedure promises simplicity and efficiency. In addition, this method does not require expensive facilities.

Micropreparation of a Native PHGPx Protein From Radish Seedlings by Immunoaffinity Chromatography / 生物化学与生物物理进展

Radish phospholipid hydroperoxide glutathione peroxidase (RsPHGPx) was identified as a mitochondrion-targeting PHGPx in previous work. To determine its cleavage site of the targeting peptide, the immunoaffinity chromatography (IAC) purification approach was carried out to isolate the native RsPHGPx protein.Polyclonal antibodies directed against recombinant RsPHGPx were raised in rabbit. Monospecific anti-RsPHGPx antibodies were isolated by means of affinity chromatography using the recombinant RsPHGPx as affinity ligand, and employed in assembling an IAC column. A single-step, highly specific and easy-to-use protocol was developed for purification of the active RsPHGPx protein through the assembled IAC column. Using this approach, a specific protein of the expected molecular size was obtained from the mitochondrial fraction of radish seedlings. Western blot analysis showed that it could be specifically recognized by anti-RsPHGPx antibodies, and an enzyme activity assay indicated that it exhibited significant PHGPx activity, suggesting that the purified protein should be the desired native RsPHGPx. These results will lead to clarification of the targeting peptide and the active mature protein of RsPHGPx and will be helpful to further probe the intracellular localization mechanism and biological fun ction of this plant PHGPx.

Expression of the rice hoja blanca virus (RHBV) non-structural protein 3 (NS3) in Escherichia coli and its in situ localization in RHBV-infected rice tissues

The non-structural NS3 protein gene from the rice hoja blanca virus (RHBV) was fused to the glutathione-S-transferase carboxilic end and expressed in Escherichia coli strain JM83. Large quantities of fusion protein were produced in insoluble form. The fusion protein was fractionated in SDS-PAGE and purified by electroelution, polyclonal antibodies were raised in rabbit and the antiserum was absorbed with bacterial crude extract. A band of similar size as that of NS3 protein was observed in Western blots using extracts from RHBV-infected rice plants. Immunoelectron microscopy with colloidal gold-labeled antibodies against NS3 protein and the viral nucleocapsid protein revealed in situ accumulation of NS3 protein in the cytoplasm but not in the viral inclusion bodies, vacuoles or chloroplasts of RHBV-infected plants, following the same pattern of distribution as the RHBV nucleocapsid protein.