RESUMO
Pre-existing neutralizing antibody provides the first line of defence against pathogens in general. For influenza virus, annual vaccinations are given to maintain protective levels of antibody against the currently circulating strains. Here we report that after booster vaccination there was a rapid and robust influenza-specific IgG+ antibody-secreting plasma cell (ASC) response that peaked at approximately day 7 and accounted for up to 6% of peripheral blood B cells. These ASCs could be distinguished from influenza-specific IgG+ memory B cells that peaked 14-21 days after vaccination and averaged 1% of all B cells. Importantly, as much as 80% of ASCs purified at the peak of the response were influenza specific. This ASC response was characterized by a highly restricted B-cell receptor (BCR) repertoire that in some donors was dominated by only a few B-cell clones. This pauci-clonal response, however, showed extensive intraclonal diversification from accumulated somatic mutations. We used the immunoglobulin variable regions isolated from sorted single ASCs to produce over 50 human monoclonal antibodies (mAbs) that bound to the three influenza vaccine strains with high affinity. This strategy demonstrates that we can generate multiple high-affinity mAbs from humans within a month after vaccination. The panel of influenza-virus-specific human mAbs allowed us to address the issue of original antigenic sin (OAS): the phenomenon where the induced antibody shows higher affinity to a previously encountered influenza virus strain compared with the virus strain present in the vaccine. However, we found that most of the influenza-virus-specific mAbs showed the highest affinity for the current vaccine strain. Thus, OAS does not seem to be a common occurrence in normal, healthy adults receiving influenza vaccination.
Assuntos
Anticorpos Monoclonais/biossíntese , Anticorpos Monoclonais/imunologia , Afinidade de Anticorpos/imunologia , Memória Imunológica/imunologia , Orthomyxoviridae/imunologia , Anticorpos Monoclonais/genética , Especificidade de Anticorpos/imunologia , Células Clonais/imunologia , Células Clonais/metabolismo , Clonagem Molecular , Humanos , Imunização Secundária , Imunoglobulina G/genética , Imunoglobulina G/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vírus da Influenza B/imunologia , Vacinas contra Influenza/imunologia , Modelos Imunológicos , Plasmócitos/imunologia , Plasmócitos/metabolismo , Hipermutação Somática de Imunoglobulina/genética , Fatores de Tempo , VacinaçãoRESUMO
Determination of the origin and fate of autoreactive B cells is critical to understanding and treating autoimmune diseases. We report that, despite being derived from healthy people, antibodies from B cells that have class switched to IgD via genetic recombination (and thus become class switched to C delta [C delta-CS] cells) are highly reactive to self antigens. Over half of the antibodies from C delta-CS B cells bind autoantigens on human epithelioma cell line 2 (HEp-2) cells or antinuclear antigens, and a quarter bind double-stranded DNA; both groups of antibodies are frequently polyreactive. Intriguingly, some C delta-CS B cells have accumulated basic residues in the antibody variable regions that mediate anti-DNA reactivity via somatic hypermutation and selection, while other C delta-CS B cells are naturally autoreactive. Though the total percentage was appreciably less than for C delta-CS cells, a surprising 31% of IgG memory cell antibodies were somewhat autoreactive, and as expected, about 24% of naive cell antibodies were autoreactive. We interpret these findings to indicate either that autoreactive B cells can be induced to class switch to IgD or that autoreactive B cells that use IgD as the B cell receptor are not effectively deleted. Determination of the mechanism by which the majority of C delta-CS B cells are autoreactive may be important in understanding peripheral tolerance mechanisms and may provide insight into the enigmatic function of the IgD antibody.
Assuntos
Autoimunidade/genética , Linfócitos B/imunologia , Switching de Imunoglobulina , Imunoglobulina D/genética , Imunoglobulina D/metabolismo , Adulto , Anticorpos Antinucleares/genética , Anticorpos Antinucleares/metabolismo , Autoanticorpos/genética , Autoanticorpos/metabolismo , Linfócitos B/citologia , Sequência de Bases , Diferenciação Celular , Linhagem Celular , Criança , Primers do DNA/genética , Humanos , Técnicas In Vitro , Tonsila Palatina/citologia , Tonsila Palatina/imunologiaRESUMO
Self-reactive B cells not controlled by receptor editing or clonal deletion may become anergic. We report that fully mature human B cells negative for surface IgM and retaining only IgD are autoreactive and functionally attenuated (referred to as naive IgD(+)IgM(-) B cells [B(ND)]). These B(ND) cells typically make up 2.5% of B cells in the peripheral blood, have antibody variable region genes in germline (unmutated) configuration, and, by all current measures, are fully mature. Analysis of 95 recombinant antibodies expressed from the variable genes of single B(ND) cells demonstrated that they are predominantly autoreactive, binding to HEp-2 cell antigens and DNA. Upon B cell receptor cross-linkage, B(ND) cells have a reduced capacity to mobilize intracellular calcium or phosphorylate tyrosines, demonstrating that they are anergic. However, intense stimulation causes B(ND) cells to fully respond, suggesting that these cells could be the precursors of autoantibody secreting plasma cells in autoimmune diseases such as systemic lupus erythematosus or rheumatoid arthritis. This is the first identification of a distinct mature human B cell subset that is naturally autoreactive and controlled by the tolerizing mechanism of functional anergy.