Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / As imunoglobulinas sÃo proteÃnas do soro humano que despertam maior interesse em sua utilizaÃÃo devido Ãs inÃmeras funÃÃes diagnÃsticas e terapÃuticas. Pesquisas nessa Ãrea contemplam assuntos de Ãmbito tÃcnico cientÃfico, beneficiando setores carentes no nosso paÃs no quesito da saÃde humana. Nesse contexto, o presente trabalho teve por finalidade avaliar o potencial da matriz quitosana/alginato epoxilado (QAE) com corantes reativos imobilizados, na purificaÃÃo de IgG humana utilizando a tÃcnica por cromatografia de afinidade. Os corantes Cibacron Blue F3GA, Reativo Verde 5 (Procion HE-4G) e o Reativo Azul 4 (Procion Blue MX-R) foram imobilizados nas partÃculas de quitosana/alginato epoxilada e nÃo foi observado desprendimentos desses corantes nos ensaios cromatogrÃficos. A matriz de QAE com e sem corantes imobilizados foram caracterizados por Espectroscopia de Infravermelho por Transformada de Fourier (FTIR) visando verificar os grupos especÃficos dos corantes na superfÃcie da matriz. Foi investigado a influÃncia do tipo de tampÃo e pH na adsorÃÃo de IgG de alta pureza. Os materiais apresentaram elevada capacidade de adsorÃÃo para diferentes sistemas tamponantes: MOPS (Ãcido morfolinopropanosulfÃnico), HEPES (Ãcido N-2-hidroxietilpiperazino-Nâ-2-etanosulfÃnico), MES (4 â Ãcido morfolinoetanosulfÃnico) e FS (Fosfato de SÃdio). As isotermas de adsorÃÃo foram obtidas em sistemas em batelada e os dados experimentais foram bem correlacionados pelos modelos de Langmuir e Langmuir-Freundlich. O adsorvente quitosana/alginato epoxilado com corante Reativo Azul 4 imobilizado apresentou quantidade mÃxima de adsorÃÃo de IgG superior a 180 mg/g, superando os outros materiais. Os trÃs adsorventes apresentaram constantes de dissociaÃÃo (KD e KDLF) entre 10-5 e 10-6 mol/L. Os ensaios cromatogrÃficos foram realizados com IgG de alta pureza e soro humano diluÃdo 10 vezes e realizaram-se balanÃos de massas, anÃlises de eletroforeses e quantificaÃÃo de proteÃnas totais pelo mÃtodo de Bradford. Nos ensaios em leito fixo com soro humano necessitou-se de 15,0 mL de soro diluÃdo para a saturaÃÃo do leito e as amostras coletadas das fraÃÃes cromatogrÃficas indicaram a purificaÃÃo de IgG do soro humano atravÃs da eletroforese. Entre os trÃs ligantes pseudobiespecÃficos (corantes) estudados no presente trabalho, o corante Cibacron Blue F3GA apresentou maior potencial para purificar IgG do soro humano em todos os trÃs tampÃes analisados, devido a maior seletividade deste por IgG comparado aos demais corantes imobilizados.

Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul, FAPERGS.

Estudou-se quantitativamente e qualitativamente a citologia, os teores de imunoglobulinas, e a atividade bactericida dos fagócitos do colostro bovino contra a Escherichia coli enterotoxigênica (ECET), analisando-se a influência da opsonização prévia destas células. Para tal finalidade foram utilizadas 53 vacas da raça Holandesa, das quais realizou-se a colheita de um total 212 amostras de colostro obtidas antes da primeira e segunda ordenha. As amostras positivas (n=41) ao exame bacteriológico do leite foram excluídas desta pesquisa. Para a análise citológica quantitativa e qualitativa do colostro, foram utilizadas as técnicas de microscopia direta e citocentrifugação, respectivamente. As dosagens das imunoglobulinas (IgG, IgM e IgA) foram realizadas por meio da técnica de imunodifusão radial, utilizando-se Kits comerciais. Para a avaliação da atividade bactericida indireta dos fagócitos e verificação da influência da opsonização prévia da ECET, foram realizados os seguintes ensaios: utilizando somente suspensão de fagócitos mononucleares e polimorfonucleares em meio de cultura (Grupo Controle - C); suspensão de fagócitos mononucleares e polimorfonucleares adicionados a suspensão de ECET não opsonizada (Grupo NO); suspensão de fagócitos mononucleares e polimorfonucleares adicionados a suspensão de ECET previamente opsonizada com 10% de sobrenadante de colostro bovino delipidado (Grupo O). A atividade bactericida indireta dos fagócitos foi mensurada por meio da quantidade de nmoles de peróxido de hidrogênio liberado por estas células, nos ensaios C, NO e O. Após as avaliações dos resultados das determinações realizadas, conclui-se que: (1) o colostro bovino de segunda ordenha apresenta maior quantidade de células/mL, que aquele de primeira ordenha; (2) a predominância celular demonstrada com o uso das técnicas de microscopia direta e de citocentrifugação foi de células mononucleares; (3) colostro bovino de segunda ordenha possui maior quantidade de neutrófilos polimorfonucleares, quando comparada àquela da primeira ordenha, utilizando as técnicas de microscópica direta e de citocentrifugação, para a contagem dos tipos leucocitários; (4) os tipos celulares predominantes no colostro bovino de primeira e segunda ordenha foram macrófagos/células epiteliais, seguidos por linfócitos, neutrófilos e eosinófilos, respectivamente, utilizando a técnica de citocentrifugação para diferenciação celular; (5) o colostro bovino de primeira ordenha possui maiores teores de imunoglobulinas das classes G e M, que o da segunda ordenha, havendo predomínio da IgG, sobre a IgM e IgA independente da ordem de ordenha. (6) os fagócitos do colostro bovino de primeira ordenha apresentaram maior atividade celular avaliada pela liberação de peróxido de hidrogênio, que os da segunda ordenha; (7) a estimulação antigênica com ECET não foi suficiente para aumentar a atividade bactericida dos fagócitos do colostro bovino; (8) a opsonização da ECET com soro colostral não determinou diferenças significativas na atividade bactericida dos fagócitos do colostro bovino, mensurada pela quantidade de peróxido de hidrogênio liberado por estas células; (9) existe correlação positiva entre os teores de imunoglobulinas da classe M e a quantidade de peróxido de hidrogênio liberado pelos fagócitos do colostro bovino; (10) o comportamento quantitativo observado para as imunoglobulinas e células do colostro bovino, considerando a ordem das ordenhas, sugere que os anticorpos teriam função prioritária na imunidade do neonato, enquanto o aumento de neutrófilos estaria voltado aparentemente para a proteção da glândula mamária. / Bovine collostrum citology, immunoglobulin content and bactericidal activity of phagocytes against enterotoxigenic Escherichia coli were studied qualitatively and quantitatively, analyzing the influence of previous opsonization of the bacterium. In order to achieve this aim, 53 Holstein cows were used to obtain 212 collostrum samples before the first and second milkings. Samples positive (n=41) in the bacteriological examination of milk were excluded from the trial. Direct microscopy and cytocentrifugation were used in the quantitative and qualitative cytological analysis of collostrum, respectively. Immunoglobulin (IgG, IgM and IgA) contents were determined by means of radial immunodiffusion using commercial kits. Indirect bactericidal activity of phagocytes and assessment of the influence of ETEC previous opsonization were carried out as follows: using only a suspension of mononuclear and polymorphonuclear phagocytes in culture medium (Control group - C); suspension of mononuclear and polymorphonuclear phagocytes added to a suspension of non-opsonized ETEC (NO group); suspension of mononuclear and polymorphonuclear phagocytes added to an ETEC suspension previously opsonized with 10% of supernatant of delipidated bovine collostrum (O group). Indirect bactericidal activity of phagocytes was measured by means of the amount of hydrogen peroxide nmoles released by these cells in assays C, NO and O. After results were evaluated, it was concluded that: (1) bovine collostrum obtained in the second milking showed more cells/mL than first milking collostrum; (2) the predominance of mononuclear cells was determined by both direct microscopy and cytocentrifugation; (3) bovine collostrum obtained in the second milking showed greater quantity of polymorphonuclear neutrophils than that of the first milking, as determined in cell type counts by direct microscopy and cytocentrifugation; (4) cell types predominating in bovine collostrum of the first and second milking were macrophages / epithelial cells, followed by lymphocytes, neutrophils and eosinophils, respectively, using cytocentrifugation for cell differentiation; (5) first milking bovine collostrum showed greater levels of immunoglobulins G and M than that of the second milking, with a predominance of IgG compared with IgM and IgA, no matter the milking order; (6) phagocytes in first milking collostrum showed greater cell activity than those in the second milking collostrum, as evaluated by hydrogen peroxide release; (7) antigenic stimulation of ETEC was not enough to increase bactericidal activity of phagocytes in bovine collostrum; (8) ETEC opsonization with collostral serum did not lead to significant differences in bactericidal activity of bovine collostrum phagocytes, as measured by the amount of hydrogen peroxide released by these cells; (9) there was a positive correlation between the contents of immunoglobulin M and the amount of hydrogen peroxide released by phagocytes in bovine collostrum; (10) quantitative behavior observed for immunoglobulins and cells of bovine collostrum considering the milking order, suggest that antibodies would have a essential function in neonate immunity, whereas the increase in neutrophils would apparently be linked to mammary gland protection.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A vasectomia, como mÃtodo de contracepÃÃo, poderà ser revertida em situaÃÃes especiais, atravÃs dos procedimentos cirÃrgicos; porÃm, o desenvolvimento de respostas humorais auto-imunes pÃs-vasectomia, em alguns, poderà ser um impeditivo para restaurar a fertilidade. Neste contexto, investigaÃÃes sobre a incidÃncia e evoluÃÃo das respostas auto-imunes em vasectomizados poderÃo oferecer subsÃdios, tanto para a compreensÃo da infertilidade auto-imune associada à vasectomia, quanto para avaliaÃÃo do sucesso nos esforÃos para restauraÃÃo da fertilidade nestes indivÃduos. Foram selecionados 20 voluntÃrios com desejo manifesto de se submeterem à vasectomia; encaminhados, na sua maioria, pela Maternidade Escola Assis Chateaubriand. As vasectomias foram realizadas pelo autor da pesquisa, no AmbulatÃrio de Cirurgia da Faculdade de Medicina. Amostras de sangue e sÃmen foram colhidas antes e 30, 90 e 180 dias apÃs a vasectomia, e a presenÃa das IgG e IgA, avaliada no Centro de ReproduÃÃo Assistida do Cearà (CONCEPTUS), atravÃs do Imunobead Test (IBT), com o mÃtodo direto para amostras prÃ-cirÃrgicas de sÃmen e o mÃtodo indireto para as amostras seminais posteriores e as de soro. Os anticorpos foram detectados nos soro e/ou sÃmen, nas positividades de >0% (todas as reaÃÃes positivas) e ≥ 20% de espermatozÃides ligados Ãs imunoglobulinas. Foram estudadas: i) avaliaÃÃes comparativas das incidÃncias das IgG e/ou IgA , ii) evoluÃÃes dos tÃtulos dos anticorpos em funÃÃo do tempo, e iii) anÃlises dos sÃtios de ligaÃÃo dos anticorpos nos espermatozÃides de voluntÃrios. Nenhuma das amostras prÃ-vasectomia revelou presenÃa de anticorpos antiespermatozÃides; porÃm IgG e IGA estavam presentes no soro e sÃmen simultaneamente nas amostras pÃs-vasectomia da maioria dos indivÃduos, revelando crescimento progressivo de 30 atà 180 dias. A presenÃa conjunta dos anticorpos sempre se mostrou predominante. Na positividade de >0%, 25% dos vasectomizados eram positivos em 30 dias, com IgG ou IgA presentes, individualmente, em poucos. Em 90 dias, 60% dos vasectomizados revelou presenÃa dos anticorpos, o que aumentou para 85% em 180 dias. A positividade de ≥ 20% nÃo foi encontrada em nenhum dos indivÃduos. Em exames de soro, isoladamente, a positividade de ≥ 20% aumentou de um indivÃduo em 30 dias, para trÃs em 90 dias, e para quatro (25%) em 180 dias. No sÃmen, esta positividade nÃo foi detectada em nenhum indivÃduo. AvaliaÃÃes dos tÃtulos de anticorpos (% de espermatozÃides ligados aos anticorpos), revelaram que as IgG e IgA aumentaram progressivamente com tempo, tanto no soro quanto no sÃmen, com a IgG sempre na dianteira; atingindo, aos 180 dias, os valores mÃdios de 7,90% (mediana â 5%) e 6,35% (mediana - 4,50%); respectivamente para IgG e IgA. A peÃa intermediÃria (PI) e cauda do espermatozÃide, nesta ordem, foram os principais sÃtios de ligaÃÃo das IgG e IgA. Esses resultados mostram que um nÃmero significativo de atà 85% dos vasectomizados desenvolve as IgG e IgA antiespermatozÃides nos primeiros 180 dias; com a positividade crescente que alcanÃa ≥ 20% em alguns; o que poderÃ, em tese, comprometer as tentativas futuras de restauraÃÃo da fertilidade nestes indivÃduos. / The contraceptive method of vasectomy can be reversed, in certain circumstances, through surgical procedures; but the incidence of autoimmune antisperm humoral responses in some vasectomized individuals may impede attempts to restore fertility. In this context, investigations on the incidence and evolution of autoimmune responses in vasectomized individuals may contribute for the understanding of autoimmune infertility associated with vasectomy, as also for the assessment of viability of restorative surgeries for fertility. Twenty individuals who have requested voluntary vasectomy for contraception, most referred by the Assis Chateaubriand School of Maternity of the Federal University of CearÃ, were selected for the study. Surgical vasectomy was performed by the author, in the Ambulatory ward of the Faculty of Medicine. Blood and semen samples were collected from the individuals prior to, and 30, 90 and 180 days after vasectomy. Antisperm IgG and IgA were evaluated in the Center for Assisted Reproduction of Cearà (CONCEPTUS), by âImmunobeadâ technique (IBT), using the direct method for the detection of antibodies in pre-vasectomy seminal samples, and the indirect IBT for evaluation of antibodies in semen samples after vasectomy, and for sera. Antibody presence was measured as >0% (all positive results) and ≥ 20% of spermatozoa bound to antibodies. The parameters studied were: i) comparative evaluations of the incidences of IgG and/or IgA in serum and/or semen; ii) evolution of the titers of these antibodies with time; and iii) the sites of binding of the antibodies in the spermatozoa of volunteers. All the pre-vasectomy serum and semen samples were devoid of antisperm antibodies; however, IgG and/or IgA were present in post-vasectomy serum and semen samples in a majority of individuals, in increasing numbers from 30 to 180 days. The simultaneous presence of IgG and IgA was always predominant. At >0% positivity, 25% of the individuals were positive in 30 days, with IgG or IgA individually present in very few. In 90 days, 60% of the vasectomized were positive, rising to 85% in 180 days. No positive reactivity was detected for ≥ 20%. Evaluation of antibodies in serum individually showed that positive results at ≥ 20% increased from one (30 days) to three in 90days, and to four in 180 days. In semen, this positivity was not detected. The evaluation of antibody titers (% of spermatozoa bound to antibodies) revealed increase of IgG and IgA with time both in serum and semen, with the former always ahead of IgA, and reaching mean values at 180 days of 7,9% (median â 5%) and 6,35% (4,5%); respectively for IgG and IgA. The midpiece and the tail of spermatozoa were the principal binding sites, in that order, for both IgG and IgA. These results show that up to 85% of individuals develop antisperm antibodies in 180 days after vasectomy, with a steadily increasing level of positivity reaching ≥ 20% in some; which may potentially compromise efforts to restore fertility in them.

A doença periodontal é o problema de saúde oral mais comum nos gatos adultos, cuja prevalência está estimada em até 70% dos animais. Dentre as principais etiologias, destaca-se a Porphyromonas gingivalis, importante patógeno frequentemente detectado em lesões ativas de periodontite. Nesse contexto, a imunoterapia associada ao emprego de imunoglobulinas anti-Porphyromonas gingivalis (IgY-PG) surge como alternativa promissora frente aos convencionais métodos preventivos e terapêuticos. O presente estudo objetivou avaliar a eficácia da adição de IgY - PG em dietas extrusadas sobre diferentes parâmetros relacionados a saúde oral de gatos. Foram empregados 20 gatos adultos, sem raça definida, idade média de 7,92±1,98 anos e peso corporal médio de 4,55±1,11kg. Os animais foram divididos em dois grupos experimentais de 10 gatos cada. O estudo seguiu delineamento crossover, com a duração de 40 dias em cada período experimental. Todos os animais foram previamente avaliados, para a confirmação da presença da PG na microbiota bucal pelo emprego de técnicas moleculares. Os parâmetros avaliados foram índice de placa, índice de cálculo, índice de gengivite e contagem bacteriana bucal nos momentos T0 e T40 dias após o início do estudo. Os animais alimentados com a dieta adicionada de IgY-PG apresentaram redução significativa dos índices de placa (P=0,05) e cálculo dentário (P= 0,06), achados que demonstram melhora da saúde oral dos gatos estudados. / Periodontal disease is the most common problem of oral health in adult cats, whose prevalence is estimated at up to 70% of the animals. Among the main causes, there is the Porphyromonas gingivalis, an important pathogen frequently detected in active lesions of periodontitis. In this context, immunotherapy associated with the use of IgY against - Porphyromonas gingivalis (IgY - PG) has emerged as a promising alternative to conventional preventive and therapeutic methods. The aim of this study was to evaluate the efficacy of adding IgY - PG in extruded diets on different parameters related to oral health in cats. Twenty adult cats, mixed breeds, with 7.92±1.98 years old and a mean body weight of 4.55±1.11 kg were used. The animals were divided into two groups of 10 cats each. The experiment followed crossover design, with each period lasting 40 days. All animals were previously evaluated to confirm the presence of PG in the oral microbiota by using molecular techniques. The parameters evaluated were plaque, calculus and gingivitis index, and oral bacterial count in times T0 and T40 days after the start of the study. Animals fed the diet added IgY - PG significant reduction of plaque index (P=0.05) and dental calculus (P=0.06), findings that demonstrate improved oral health of cats studied.

No description available.

Mitogen driven differentiation of mononuclear cells is a useful model of antibody synthesis and secretion in humans. We have studied Pokeweed mitogen (PWM) induced immunoglobulin secretion in vitro in both healthy individuals and multiple sclerosis patients. Within the healthy population we have identified individuals who consistently secrete low levels of IgG in response to PWM and others who secrete very high levels. The underlying mechanisms involved in low response are not well understood. We have observed that the peripheral blood mononuclear cells (PBMC) obtained from low responders differ from those obtained from high responders in each of the following: Their T-helper cell subset contains a higher ratio of T suppressor-inducer cells over T helper-inducer cells; their PBMC contain a higher level of in vivo radiation-sensitive suppression; their PBMC generate a lower autologous mixed lymphocyte response; and their B lymphocytes secrete lower amounts of IgG when mixed with heterologous high responder T helper cells. These results suggest the response involves the interactions between T helper cell subsets, T suppressor cells and B lymphocytes and that the level of response is the sum of the contribution of each subset. PWM induced immunoglobulin secretion was measured in multiple sclerosis patients during different phases of clinical disease activity. Relapsing-remitting multiple sclerosis patients in early relapse secreted less immunoglobulin than patients with prolonged relapse, suggesting that immune function varies with clinical disease activity. Testing the level of PWM induced immunoglobulin secretion in relapsing-remitting multiple sclerosis patients during the clinically stable phase suggested that those patients who secreted high levels of IgG in response to PWM were more likely to suffer a clinical relapse within 6 months than those patients who secreted a low amount. Chronic progressive multiple sclerosis patients secreted higher amounts of immunoglobulin in this assay than healthy control individuals. This group of multiple sclerosis patients also had; (i) reduced Concanavalin A (Con A) suppressor cell activity measured both by the ability to suppress a/ Con A induced proliferation and b/ PWM induced IgG secretion in heterologous cell cultures and; (ii) reduced percentages of T cells expressing T suppressor and T suppressor-inducer markers. The treatment of chronic progressive multiple sclerosis patients in vivo with lymphoblastoid interferon resulted in a dramatic reduction in level of PWM induced immunoglobulin secretion without alteration in Concanavalin A induced suppression or in the percentages of T cells expressing subset specific markers. The PWM induced IgG secretion assay is a valuable technique for investigating the regulation of humoral immunity in both health and disease. / Medicine, Faculty of / Pathology and Laboratory Medicine, Department of / Graduate

Nesse trabalho foram estudadas 2 estratégias visando a purificação de IgM a partir de plasma humano. A primeira estratégia baseou-se em um processo desenhado para a fábrica de produção de hemoderivados do Instituto Butantan para a produção dos fatores de coagulação VIII e IX, albumina e IgG. Após 2 colunas cromatográficas, a IgM foi separada das 2 proteínas mais abundantes do plasma, a albumina e a IgG e o enriquecimento da IgM em relação a IgA e IgG foi bastante satisfatória. A segunda estratégia está inserida no processo de fracionamento de plasma desenvolvida em nosso laboratório. Através de um estudo sistemático em coluna de troca aniônica, obtivemos uma fração contendo IgG, uma contendo albumina, ambos praticamente puros e uma terceira contendo IgM e outras proteínas contaminantes. Os resultados obtidos indicam que a IgM pode ser purificada com sucesso empregando ambas as estratégias. Entretanto, para se obter um produto mais homogêneo, será necessário ainda adicionar uma ou mais etapas de purificação. / In this work we studied two strategies for the purification human plasma IgM. The first strategy was based on a process designed for the hemoderivatives production factory of the Butantan Institute for the production of coagulation factors VIII and IX, albumin and IgG. After 2 chromatographies, IgM was separated from the 2 most abundant plasma proteins, that is, albumin and IgG and the achieved enrichment of IgM in relation to IgG and IGA was very satisfactory. The second strategy is part of a plasma fractionation process under development in our laboratory. Through a systematic study using an anionic exchange column we separated a fraction containing IgG, a second containing albumin, being both nearly pure and a third fraction containing IgM and other contaminating proteins. The obtained results indicate that IgM can be purified successfully by both strategies. However, to obtain a more homogeneous product, additional purification steps are necessary.

The gut microbiota and its metabolites – namely short chain fatty acids (SCFAs) – interact with the digestive, immune, and nervous systems. Microbiota with disrupted composition are highly associated with obesity, gastrointestinal symptoms, and chronic inflammation. Levels of SCFAs in the feces can represent dynamics of the microbiota, and they represent one mechanism by which the microbiota interacts with its host. This study aimed to further our understanding of associations between microbiota bacterial diversity and SCFAs, immune markers, BMI, and GI symptoms and to identify bacteria that are differentially abundant in different BMI groups and with synbiotic supplementation. Data (SCFAs, immunoglobulins, body mass index, fecal fiber, fecal protein, measures of GI symptoms, and 16s RNA sequences, n=11) was extracted from a randomized control trial investigating the effects of synbiotic supplementation in non-celiac gluten-sensitive participants. QIIME2 was used to process 16s RNA data, analyze quantitative, qualitative, phylogenetic quantitative, and phylogenetic qualitative measures of alpha and beta diversity and to perform an analysis of composition of microbiomes (ANCOM) for identification of differential abundances. Multiple metrics of alpha diversity were found to significantly correlate with IgG4, IgM, IL-2, acetate, propionate, isobutyrate, valerate, isovalerate, caproate, heartburn, urgent need to defecate, and feelings of incomplete evacuation. Multiple metrics of beta diversity were significantly different between normal and overweight, normal and obese, and overweight and obese BMI classification groups. Beta diversity was also found to significantly correlate with IgG1, IgG3, IgG4, IgA, IL-6, IL-8, fecal fiber, propionate, butyrate, heartburn, acid regurgitation, nausea and vomiting, bloating, abdominal distension, increased gas, and eructation. The synbiotic intervention did not significantly alter alpha or beta diversity. An ANCOM identified bacterial taxa differentially abundant with BMI shifts and synbiotic supplementation, though these taxa were not those included in the synbiotic. Findings demonstrate alpha and beta diversity associations with various SCFAs, GI symptoms, immune markers, and BMI, and the results of the placebo-controlled intervention suggest careful consideration of placebo contents moving forward. This research supports plans to apply analysis to larger sample sizes to elucidate changes microbial profiles that are associated with clinically relevant biomarkers and symptoms.

Hepatitis C virus (HCV) infection is characterized by a strong propensity toward chronicity, autoimmune phenomena and lymphomagenesis, supporting a role for lymphocyte dysregulation during persistent viral infection. We have shown that HCV core protein inhibits T-cell functions through interaction with a complement receptor, gC1qR. Here, we further report that B cells also express gC1qR that can be bound by HCV core protein. Importantly, using flow cytometry, we demonstrated differential regulation of B and T lymphocytes by the HCV core-gC1qR interaction, with down-regulation of CD69 activation in T cells but up-regulation of CD69 activation and cell proliferation in B cells. HCV core treatment led to decreased interferon-γ production in CD8+ T cells but to increased immunoglobulin M and immunoglobulin G production as well as cell surface expression of costimulatory and chemokine receptors, including CD86 (B7-2), CD154 (CD40L) and CD195 (CCR5), in CD20+ B cells. Finally, we showed down-regulation of suppressor of cytokine signalling-1 (SOCS-1) using real-time reverse transcription-polymerase chain reaction, accompanied by up-regulation of signal transducer and activator of transcription-1 (STAT1) phosphorylation in B cells in response to HCV core protein, with the opposite pattern observed in HCV core-treated T cells. This study demonstrates differential regulation of B and T lymphocytes by HCV core and supports a mechanism by which lymphocyte dysregulation occurs in the course of persistent HCV infection.