Avaliação de antígeno leucocitário humano classe I e II em pacientes pediátricos com gastrite e úlcera duodenal ativas e Helicobacter pylori positivo / Evaluation of human leukocyte antigen class i and ii antigens in helicobacter pylori-positive pediatric patients with active gastritis and duodenal ulcer

ABSTRACT BACKGROUND: As being the first bacteria determined to be carcinogenic, Helicobacter pylori (H. pylori) is a pathogen localized in the stomach in more than half of the world population. Some earlier studies have found a relation between tissue histocompatibility antigens and gastric cancers depending on the regions. OBJECTIVE: The present study aimed to determine the distribution of human leukocyte antigen (HLA) class I and class II antigens in H. pylori-positive pediatric patients with active gastritis and duodenal ulcer, excluding cancer cases, in our center. METHODS: The study included 40 patients diagnosed with H. pylori-positive active gastritis and duodenal ulcer and 100 controls consisting of healthy donor candidates. The HLA class I and class II antigens were studied in the isolated DNA samples using the polymerase chain reaction sequence-specific oligonucleotide probes. RESULTS: The frequency of HLA-B*51 antigen was significantly higher in the patient group than in the control group (40% vs 17%; P=0.003). There was no difference between the two groups in terms of the frequencies of HLA-A, HLA-C, HLA-DR, and HLA-DQ antigens. CONCLUSION: It was determined that HLA-B*51 plays a critical role in H. pylori infection.

RESUMO CONTEXTO: Determinada como sendo a primeira bactéria cancerígena, o Helicobacter pylori (H. pylori) é um patógeno localizado no estômago em mais da metade da população mundial. Alguns estudos anteriores têm encontrado uma relação entre câncer gástrico e antígenos de histocompatibilidade de tecido dependendo das regiões. OBJETIVO: O presente estudo teve como objetivo determinar a distribuição em nosso centro do antígeno leucocitário humano (HLA) de classe I e antígenos classe II em pacientes pediátricos H. pylori-positivos com gastrite e úlcera duodenal ativas, excluindo casos de câncer. MÉTODOS: O estudo incluiu 40 pacientes H. pylori-positivos diagnosticados com gastrite e úlcera duodenal ativas e 100 controles consistindo de candidatos doadores saudáveis. Foram estudadas nas amostras de DNA isoladas o antígeno leucocitário humano classe I e antígenos classe II, utilizando-se as cadeias de sequência específica de polimerase do oligonucleotideo. RESULTADOS: A frequência do antígeno HLA - B * 51 foi significativamente maior no grupo de pacientes do que no grupo controle (40% vs 17%; P=0,003). Não houve diferença entre os dois grupos em termos das frequências dos antígenos HLA-A, HLA-DR, HLA-DQ e HLA-C. CONCLUSÃO: Determinou-se que o HLA - B * 51 desempenha um papel crítico na infecção pelo H. pylori.

Analyses of the TCR repertoire of MHC class II-restricted innate CD4+ T cells

Analysis of the T-cell receptor (TCR) repertoire of innate CD4+ T cells selected by major histocompatibility complex (MHC) class II-dependent thymocyte-thymocyte (T-T) interaction (T-T CD4+ T cells) is essential for predicting the characteristics of the antigens that bind to these T cells and for distinguishing T-T CD4+ T cells from other types of innate T cells. Using the TCRmini Tg mouse model, we show that the repertoire of TCRalpha chains in T-T CD4+ T cells was extremely diverse, in contrast to the repertoires previously described for other types of innate T cells. The TCRalpha chain sequences significantly overlapped between T-T CD4+ T cells and conventional CD4+ T cells in the thymus and spleen. However, the diversity of the TCRalpha repertoire of T-T CD4+ T cells seemed to be restricted compared with that of conventional CD4+ T cells. Interestingly, the frequency of the parental OT-II TCRalpha chains was significantly reduced in the process of T-T interaction. This diverse and shifted repertoire in T-T CD4+ T cells has biological relevance in terms of defense against diverse pathogens and a possible regulatory role during peripheral T-T interaction.

Two Cases of Transfusion-related Acute Lung Injury Triggered by HLA and Anti-HLA Antibody Reaction

Transfusion-related acute lung injury (TRALI) is a serious adverse transfusion reaction that is presented as acute hypoxemia and non-cardiogenic pulmonary edema, which develops during or within 6 hr of transfusion. Major pathogenesis of TRALI is known to be related with anti-HLA class I, anti-HLA class II, or anti-HNA in donor's plasma. However, anti-HLA or anti-HNA in recipient against transfused donor's leukocyte antigens also cause TRALI in minor pathogenesis and which comprises about 10% of TRALI. Published reports of TRALI are relatively rare in Korea. In our cases, both patients presented with dyspnea and hypoxemia during transfusion of packed red blood cells and showed findings of bilateral pulmonary infiltrations at chest radiography. Findings of patients' anti-HLA antibodies and recipients' HLA concordance indicate that minor pathogenesis may be not as infrequent as we'd expected before. In addition, second case showed that anti-HLA class II antibodies could be responsible for immunopathogenic mechanisms, alone.

Legionella lipoprotein activates toll-like receptor 2 and induces cytokine production and expression of costimulatory molecules in peritoneal macrophages

Legionella bacterium, an intracellular pathogen of mononuclear phagocytes, causes acute fatal pneumonia, especially in patients with impaired cellular immune responses. Until recently, however, the toll-like receptor (TLR) engagement of bacterial proteins derived from Legionella is uncertain. We previously showed that a 19-kDa highly conserved peptidoglycan-associated lipoprotein (PAL) of Legionella pneumophila induced the PAL-specific B cell and T cell responses in mice. In this study, we observed that the rPAL antigen of L. pneumophila, as an effector molecule, activated murine macrophages via TLR2 and produced proinflammatory cytokines such as IL-6 and TNF-alpha. In both BALB/c and TLR4-deficient C3H/HeJ mice, pretreatment of macrophages with anti-TLR2 mAb showed severely impaired cytokine production in response to the rPAL. In addition, in vitro the rPAL treatment increased the cell surface expression of CD40, CD80, CD86 and MHC I/II molecules. We further showed that the synthetic CpG-oligodeoxynucleotides (CpG ODN) coadministered with the rPAL enhanced IL-12 and IL-6 production and expression of CD40, CD80 and MHC II compared to the rPAL treatment alone. In conclusions, these results indicate that Legionella PAL might activate macrophages via a TLR2-dependent mechanism which thus induce cytokine production and expression of costimulatory and MHC molecules.

Comparative Evaluation of ELISA and Luminex Panel Reactive Antibody Assays for HLA Alloantibody Screening / 대한진단검사의학회지

BACKGROUND: For the detection of HLA antibodies, solid-phase tests using purified HLA antigens are increasingly used. In this study, we analyzed the panel reactive antibody (PRA) test results using ELISA and Luminex methods, and the results were compared with those of crossmatch test. METHODS: A total of 111 sera including 90 sera from kidney transplanted patients were tested. ELISA-PRA was performed using Lambda Antigen Tray Class I and II Mixed kits (One Lambda Inc., USA) and additional test was performed to identify HLA specificities. Luminex-PRA tests were performed using LABScreen Mixed kits (One Lambda Inc., USA) and LIFECODES LifeScreen Deluxe kits (Tepnel Co., USA). RESULTS: The positive rates of PRA were higher in Tepnel (P=0.006) and One Lambda Luminex (P<0.001) methods than ELISA, without significant difference between two Luminex methods (P=0.087). The overall concordance rate among the three PRA tests was 62.2% (69/111). The positive and negative predictive values of PRA tests for the flow cytometric crossmatch were 33.3-45.7% and 85.7-89.5%, respectively. Of the two Luminex methods, One Lambda showed higher positive rate than Tepnel for the detection of class I antibodies. The sensitivity of pretransplant PRA for the detection of posttransplant acute rejection episodes was higher in Luminex (P=0.007 for Tepnel, P=0.003 for One lambda) than ELISA method. CONCLUSIONS: Different methods used to detect HLA antibodies showed discrepant results. As the Luminex method was more sensitive than ELISA for the detection of HLA antibodies, it can be used as a routine test in the transplantation laboratory.

Low expression of antigen-presenting and costimulatory molecules by lung cells from tuberculosis patients

Costimulatory and antigen-presenting molecules are essential to the initiation of T cell immunity to mycobacteria. The present study analyzed by immunocytochemistry, using monoclonal antibodies and alkaline phosphatase-anti-alkaline phosphatase method, the frequency of costimulatory (CD86, CD40, CD40L, CD28, and CD152) and antigen-presenting (MHC class II and CD1) molecules expression on human lung cells recovered by sputum induction from tuberculosis (TB) patients (N = 22) and non-TB controls (N = 17). TB cases showed a statistically significant lower percentage of HLA-DR+ cells than control subjects (21.9 ± 4.2 vs 50.0 ± 7.2 percent, P < 0.001), even though similar proportions of TB cases (18/22) and control subjects (16/17, P = 0.36) had HLA-DR-positive-stained cells. In addition, fewer TB cases (10/22) compared to control subjects (16/17) possessed CD86-expressing cells (P = 0.04; OR: 0.05; 95 percentCI = 0.00-0.51), and TB cases expressed a lower percentage of CD86+ cells (P = 0.04). Moreover, TB patients with clinically limited disease (£1 lobe) on chest X-ray exhibited a lower percentage of CD86-bearing cells compared to patients with more extensive lung disease (>1 lobe) (P = 0.02). The lower expression by lung cells from TB patients of HLA-DR and CD86, molecules involved in antigen presentation and activation of T cells, may minimize T cell recognition of Mycobacterium tuberculosis, fostering an immune dysfunctional state and active TB.

Evidence for lipopolysaccharide-induced differentiation of RAW264.7 murine macrophage cell line into dendritic like cells.

Effect of lipopolysaccharide (LPS) on RAW264.7 macrophage cell line was studied. LPS-treated RAW264.7 cells increased in cell size and acquired distinct dendritic morphology. At the optimal dose of LPS (1 mg/ml), almost 70% RAW264.7 cells acquired dendritic morphology. Flow cytometric studies indicate that the cell surface markers known to be expressed on dendritic cells and involved in antigen presentation and T cell activation (B 7.1, B 7.2, CD40, MHC class II antigens and CD1d) were also markedly upregulated on LPS-treated RAW 264.7 cells. Our results suggest the possibility that LPS by itself could constitute a sufficient signal for differentiation of macrophages into DC-like cells.

Effect of immunization with lipid associated polysaccharide antigen and anti CD-2 antibodies on class II MHC expression and cellular immune response in BALB/C mice infected with Leishmania donovani.

In a bid to characterize the antigens and immunization mechanisms which may be used to produce a protective response against L. donovani, role of lipid associated polysaccharide (LPS) antigen and whole antigen was evaluated. BALB/C mice were immunized with whole or LPS antigen in combination with one of three putative adjuvents (anti CD-2 antibody/FIA/0.85% Saline). LPS antigen emulsified in anti CD-2 antibody was found to induce significant antibodies in mice on day 28 against challenge with lethal dose of L. donovani. Immunoprophylactic properties of LPS and whole antigen was investigated on day 40 through cytokine elicitation (IL-2), MIF) in culture supernatants of spleen cells, but before that MHC-II expressed on macrophage was studied. The LPS antigen in combination with anti CD-2 antibody was found to be most immuno-reactive inducing higher MHC-II expression on macrophages which was associated with substantial rise in the level of MIF and IL-2. It coincided with decline in antibody titre in 100% mice immunized with LPS antigen while Leishmania injected as whole antigen failed to induce specific macrophage and T-cell response with all the above formulations. We surmise from our data that lipid associated polysaccharide antigen linked to anti CD-2 antibody has potential for eliciting protective immunity against Leishmania.

Aloinmunización a antígenos eritrocitarios y su epidemiología / Epidemiology of alloimmunization to erythrocytic antigens

La formación de anticuerpos frente a los antígenos eritrocitarios puede ocurrir tras una transfusión, un embarazo o un trasplante de tejidos. La naturaleza de la respuesta inmune a los antígenos sanguíneos, y su variedad individual, depende de los siguientes factores: inmunogenicidad del antígeno, dosis, intervalo entre las dosis, la vía de administración y la disposición genética del huésped. Afortunadamente, la mayoría de los antígenos eritrocitarios son poco inmunogénicos. De hecho, de todos los pacientes que son transfundidos, menos del 1 por ciento forman anticuerpos. La incidencia de la aloinmunización a antígenos eritrocitarios depende de las características demográficas de la población estudiada. La edad, el género, la raza, el tipo de hospital y de subpoblación (donantes, pacientes ingresados, pacientes obstétricos) hacen difícil la extrapolación de los resultados de una institución. Nosotros hemos estudiado la distribución de los anticuerpos irregulares en una población caucasiana estable, geográficamente aislada, ubicada en el condado de Olmsted, Minnesota. En general, nuestros resultados mostraron similitudes con algunos de los estudios anteriormente publicados. Pero lo que verdaderamente diferencia nuestro estudio es que, dado que nos hemos basado en una población homogénea, nuestros resultados sí pueden ser extrapolables a cualquier otra población caucasiana con similares características epidemiológicas.

Los antigenos del complejo mayor de histocompatibilidad clase II: regulacion y relacion con infecciones intracelulares / Antigen of major histocompatibility complex class II

Objetivo. Revisar la literatura relacionada con la modulación de la expresión de los antígenos del complejo mayor de histocompatibilidad (MHC), con énfasis en los denominados clase II, durante infecciones intracelulares, y las posibles consecuencias de dicha modulación en la patología causada por la infección. Fuente de los datos. Se extrajeron resultados obtenidos de artículos originales acerca del tema de interés, publicados en las principales revistas de Inmunología y Biología Molecular, además de información obtenida de revisiones publicadas previamente por expertos en el área. Selección de los datos. Todos los datos fueron obtenidos de trabajos originales publicados durante los últimos 20 años, que abordaran experimentalmente el tema de las consecuencias de infecciones intracelulares sobre la expresión de los antígenos clase II del MHC, principalmente aquellos relacionados con las infecciones micobacterianas. Extracción de los datos. Se incluyeron aquellos datos que tuvieran relevancia en áreas como la regulación de la expresión de los antígenos del MHC, la trasducción de señales por la vía del interferón (IFN) yR, la fosforilación o defosforilación de tirosina, el control por diferentes citoquinas de la expresión de los antígenos del MHC, y las alteraciones de la expresión de los MHC en macrófagos por patógenos intracelulares. Síntesis de los datos. Los genes del MHC codifican moléculas críticas en la generación de la inmunidad adquirida, y por ende en el eficiente control de los patógenos intracelulares. El entendimiento reciente de los detallados mecanismos que regulan la expresión de los genes del MHC ha abierto una nueva vía para el entendimiento de cómo los patógenos intracelulares, incluyendo el Mycobacterium tuberculosis, agente causal de la tuberculosis en humanos, además de infecciones por virus o protozoarios, son capaces de modular negativamente componentes de la defensa del huésped. Más aún, la evidencia obtenida hasta el momento sugiere que un grupo diverso de microorganismos taxonómicamente distintos hayan desarrollado estrategias comunes para evadir el reconocimiento inmune por el huésped. Conclusiones...

Construction of a hibrid plasmid coding for adherence antigen k88AB as well as the B subunit of Escherichia coli thermo-labile enterotoxin and mouse immune response to the encoded antigens

Um plasmídio híbrido (pUB3744) codificando para o antígeno de aderência K88ab e para a subunidade B da enterotoxina termo-lábil (LT-B) de Escherichia coli foi construído pela ligaçäo dos plasmídios pFM205 (K88ab) e pUB1844(LT-B). Estes 3 plasmídios foram subsequentemente transferidos para a amostra de E.coli O45:K, isolada de suíno, obtendo-se variantes K88ab, LT-B e K88ab/LT-B. Estas variantes foram inoculadas inoculadas por via oral em grupos de camundongos durante cinco dias consecutivos. A resposta de anticorpos isotipo-específica para K88ab, LT-B e para antígeno de bactérias sonicadas foi medida no soro e em raspados da mucosa intestinal cinco dias após a última inoculaçäo. A excreçäo da bactéria foi avaliada cultivando-se amostras de fezes. A bactéria LT-B foi eliminada por mais tempo pelos camundongos e induziu uma resposta imune local para LT-B (IgA, IgG e IgM). Näo foram detectados anticorpos para K88ab nos camundongos inoculados com a bactéria produzindo somente K88ab, mas o grupo de camundongos inoculados com as variantes 045:K apresentaram um aumento de anticorpos séricos para o antígeno de bactérias sonicadas e os níveis foram mais elevados no grupo inoculado com a variante K88ab/LT-B

Hepatitis B vaccine--proposal for a standardized assessment of immune response

The authors developed a comparative study of the various methods of assessment of immune response to Hepatitis B vaccine. Eighty-six health care professionals underwent a vaccination programme with three doses of plasma-derived vaccine against Hepatitis B (H-B-Vax, Merck, Sharp & Dohme) given intramuscularly. Assessment of immune response was carried out three months after the end of the programme, by radioimmunoassay (RIA) and enzyme immunoassay (EIA). The results showed that the semi-quantitative assessment of Anti-HBs antibodies by RIA or EIA was perfectly comparable to the reference method (quantitative determination of antibodies by RIA). In view of these findings, the authors suggest a standardization of assessment of immune response to the vaccine, thus permitting correct planning of booster doses and easier comparison between different studies.

Disminución de linfocitos T supresores y activación de monocitos y neutrófilos durante la reacción inmediata del asma-inducida por ejercicio / Lymphocyte T supressors dicrease and monocyte and neutrophil activation during the early reaction of exercise induced asthma

Durante la broncoconstricción inducida por el ejercicio (AIE) en individuos asmáticos se producen cambios cuantitativos y cualitativos de los leucocitos en sangre periférica. Para estudiar la participación de células inmunes y accesorias de la reacción inflamatoria en el AIE, analizamos las modificaciones de las subpoblaciones de linfocitos T y de la expresión de los antígenos de histocompatibilidad clase II (la) en monocitos, además de la participación de los receptores para el tercer factor del complemento (C36) mediante su expresión en monocitos y su adhesión y consecuente activación en neutrófilos. Se estudió 20 pacientes asmáticos alérgicos, de los cuales 11 presentaron broncoconstricción después de una prueba de ejercicio estandarizada. En todos los individuos estudiados se produjo, 5 min después del ejercicio, un aumento significativo de los leucocitos sanguíneos totales y de los neutrófilos, linfocitos y monocitos. Los basófilos y eosinófilos aumentaron sólo en los AIE (+). También este grupo presentó eosinófilos más altos desde el nivel inicial. En los individuos con AIE (+) el aumento inicial de los linfocitos a los 5 min se produce a expensas de los linfocitos T supresores (CD8) los que luego comienzan a disminuir hasta alcanzar valores significativamente menores que el inicial a los 60 min después del ejercicio. Esto lleva a un aumemto de la relación CD4/CD8 a nivel periférico, que es simultáneo con el aumento en la expresión de los antígenos Ia en monocitos observados en los AIE (+). Además en estos pacientes se encontró un aumento en la expresión de los receptores C3b en monocitos y en la producción de radical superóxido por neutrófilos estimulados con zimusán y complemento, desde el momento que se inicia la broncoconstricción hasta los 60 min después del ejercicio. Estos hallazgos sugieren que en los asmáticos con AIE (+) se producen cambios en las células inmunocompetentes que pudieran estar relacionados con la participación de células inflamatorias y su eventual manifestación como hiperactividad bronquial

Resposta imune à vacina da hepatite B (Hevac B, França) em unidade de diálise / Immuneresponse to B hepatitis vaccine (Hevac B, France) in a dialysis service

Foi feita uma avaliaçäo da resposta imunológica a vacina da hepatite B (Hevac B, Instituto Pasteur, França) nos pacientes e pessoal de uma unidade de hemodiálise (HD). 88,4% (23/26) desenvolveram anticorpos contra o antígeno de superfície da hepatite B (anti-HBs) entre os elementos do pessoal da HD; 75% /12) dos pacientes adultos e 87,5% (7/8) dos pacientes infantis também desenvolveram o anticorpo, todos após seis meses da primeira dose de vacina. Nenhum dos recipientes da vacina apresentou o antígeno de superficie da hepatite B (AgABs) no sangue em qualquer momento. Ficou demonstrado alto índice de resposta a vacinaçäo contra a hepatite B no pessoal e nos pacientes da HD, particularmente nas crianças, com bons títulos de anti-HBs após quatro injeçöes da vacina Hevac B

Potencial evasivo de T. gondii a la respuesta inmunitaria del huesped / Evasive potencial of T. gondii inmune response of the host

Se han estudiado varios mecanismos por los cuales Toxoplasma gondii evade la respuesta inmunitaria del huésped. En este trabajo se describen los procesos de Toxoplasma para sobrevivir en los macrófagos: en primer lugar, impidiendo la secuencia de la crisis respiratoria y, segundo, evitando en alguna forma la unión fagosoma-lisosoma. Asimismo, se menciona el fenómeno de "capping", el cual permite eliminar, por exocitosis, los anticuerpos dirigidos contra antígenos de membrana

Identificación de antígenos de Trypanosoma cruzi mediante inmunotransferencia (western bloting) y sueros humanos chagásicos / Identification of specific antigen Trypanosoma cruzi by means of immunotransference (western bloting) and chagasic human serum

La enfermedad de chagas (tripanosomiasis americana) producida por Trypanosoma Cruzi es una endemia localizada en amplias regiones de Centro Sur América, por ello constituye un problema de salud pública. En este trabajo se efectuaron lisados totales de las formas epimastigote y tripomastigote de Trypanosoma Cruzi, cepas EP y MEN (de origen venezolano) y cepas BEC (origen brasilero), fueron separadas por electroforesis en geles de poliacrilamida en presencia de SDS, analizados por inmunotransferencia inmunoblotting. Los polipectidos inmunologicamente reactivos fueron detectados por sueros humanos chagásicos y anti-inmunoglobulina humana marcada con 125 I