RESUMEN
Although B cell development requires expression of the B cell antigen receptor (BCR), it remains unclear whether engagement of self-antigen provides a positive impact for most B cells. Here, we show that BCR engagement by self-ligand during development in vivo results in up-regulation of the Nod-like receptor member Nod1, which recognizes the products of intestinal commensal bacteria. In anti-thymocyte/Thy-1 autoreactive BCR knock-in mice lacking self-Thy-1 ligand, immunoglobulin light chain editing occurred, generating B cells with up-regulated Nod1, including follicular and marginal zone B cells with natural autoreactivity. This BCR editing with increased Nod1 resulted in preferential survival. In normal adult mice, most mature B cells are enriched for Nod1 up-regulated cells, and signaling through Nod1 promotes competitive survival of mature B cells. These findings demonstrate a role for microbial products in promoting survival of mature B cells through up-regulated Nod1, providing a positive effect of BCR engagement on development of most B cells.
Asunto(s)
Linfocitos B/fisiología , Proteínas NLR/fisiología , Proteína Adaptadora de Señalización NOD1/fisiología , Receptores de Antígenos de Linfocitos B/fisiología , Envejecimiento/fisiología , Animales , Linfocitos B/metabolismo , Técnicas de Sustitución del Gen , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Transgénicos , Transducción de Señal/fisiología , Regulación hacia ArribaRESUMEN
Expression of a germline VH3609/D/JH2 IgH in mice results in the generation of B1 B cells with anti-thymocyte/Thy-1 glycoprotein autoreactivity by coexpression of Vk21-5/Jk2 L chain leading to production of serum IgM natural autoantibody. In these same mice, the marginal zone (MZ) B cell subset in spleen shows biased usage of a set of Ig L chains different from B1 B cells, with 30% having an identical Vk19-17/Jk1 L chain rearrangement. This VH3609/Vk19-17 IgM is reactive with intestinal goblet cell granules, binding to the intact large polymatrix form of mucin 2 glycoprotein secreted by goblet cells. Analysis of a µκ B cell AgR (BCR) transgenic (Tg) mouse with this anti-goblet cell/mucin2 autoreactive (AGcA) specificity demonstrates that immature B cells expressing the Tg BCR become MZ B cells in spleen by T cell-independent BCR signaling. These Tg B cells produce AGcA as the predominant serum IgM, but without enteropathy. Without the transgene, AGcA autoreactivity is low but detectable in the serum of BALB/c and C.B17 mice, and this autoantibody is specifically produced by the MZ B cell subset. Thus, our findings reveal that AGcA is a natural autoantibody associated with MZ B cells.
Asunto(s)
Autoanticuerpos/inmunología , Subgrupos de Linfocitos B/inmunología , Células Caliciformes/inmunología , Mucina 2/inmunología , Receptores de Antígenos de Linfocitos B/inmunología , Vesículas Secretoras/inmunología , Animales , Autoanticuerpos/genética , Subgrupos de Linfocitos B/patología , Células Caliciformes/patología , Cadenas Pesadas de Inmunoglobulina/genética , Cadenas Pesadas de Inmunoglobulina/inmunología , Inmunoglobulina M/genética , Inmunoglobulina M/inmunología , Cadenas kappa de Inmunoglobulina/genética , Cadenas kappa de Inmunoglobulina/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Transgénicos , Mucina 2/genética , Receptores de Antígenos de Linfocitos B/genética , Vesículas Secretoras/genética , Vesículas Secretoras/patología , Bazo/inmunología , Bazo/patologíaAsunto(s)
Enfermedades Autoinmunes/historia , Linfocitos T CD4-Positivos/inmunología , Subunidad alfa del Receptor de Interleucina-2/historia , Activación de Linfocitos/inmunología , Autotolerancia/inmunología , Animales , Linfocitos T CD4-Positivos/patología , Células Cultivadas , Modelos Animales de Enfermedad , Femenino , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones DesnudosRESUMEN
The expression of CD25 or CD28 on T cells was examined in patients with rheumatic diseases associated with interstitial pneumonitis (IP), in order to investigate the conditions of CD4+CD25+ regulatory T cells and CD8+CD28- suppressor T cells. Fifty-five patients with various rheumatic diseases and 23 normal controls were enrolled. CD4+CD25+ T cells of patients with IP were significantly decreased in comparison with non-IP patients, and the ratio of CD8+CD28- T cells in patients with IP was significantly higher than that in non-IP patients or normal controls. These results for CD8+CD28- T cells were in accord with the decrease in CD8+CD28+ T cells, and may be related to activation-induced CD8+CD28+ T-cell death. Thus, the abnormality of CD4+CD25+ regulatory T cells may be related to the pathogenesis of IP, and the survival and activation of CD8+ T cells.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Enfermedades Pulmonares Intersticiales/inmunología , Enfermedades Reumáticas/inmunología , Linfocitos T Reguladores/inmunología , Adulto , Anciano , Anciano de 80 o más Años , Recuento de Células Sanguíneas , Antígenos CD28/metabolismo , Linfocitos T CD8-positivos/metabolismo , Femenino , Humanos , Subunidad alfa del Receptor de Interleucina-2/metabolismo , Enfermedades Pulmonares Intersticiales/sangre , Enfermedades Pulmonares Intersticiales/complicaciones , Masculino , Persona de Mediana Edad , Enfermedades Reumáticas/complicaciones , Linfocitos T Reguladores/metabolismo , Adulto JovenRESUMEN
Antigen receptor-mediated signaling is critical for the development and survival of B cells. However, it has not been established whether B cell development requires a signal from self-ligand engagement at the immature stage, a process known as "positive selection." Here, using a monoclonal B cell receptor (BCR) mouse line, specific for the self-Thy-1/CD90 glycoprotein, we demonstrate that BCR crosslinking by low-dose self-antigen promotes survival of immature B cells in culture. In spleen, an increase in BCR signaling strength, induced by low-dose self-antigen, directed naive immature B cells to mature, not into the default follicular B cell fate, but instead into the marginal-zone B cell subset. These data indicate that positive selection can occur in developing B cells and that BCR signal strength is a key factor in deciding between two functionally distinct mature B cell compartments in the microenvironment of the spleen.
Asunto(s)
Linfocitos B/citología , Diferenciación Celular/inmunología , Supresión Clonal/inmunología , Bazo/inmunología , Animales , Autoanticuerpos/inmunología , Autoantígenos/inmunología , Linfocitos B/inmunología , Línea Celular , Ensayo de Inmunoadsorción Enzimática , Citometría de Flujo , Técnica del Anticuerpo Fluorescente , Ratones , Ratones Transgénicos , Receptor Notch2 , Receptores de Antígenos de Linfocitos B/inmunología , Receptores de Superficie Celular/inmunología , Receptores de Superficie Celular/metabolismo , Bazo/citología , Antígenos Thy-1/inmunologíaRESUMEN
Using 2-dimensional electrophoresis and ion-pair chromatography, we have identified elements of proliferating cell nuclear antigen (PCNA) multiprotein complexes that are reactive to antibodies in sera from patients with systemic lupus erythematosus. Among the various elements of the complexes, a 37 kDa protein (PI 8.5) that specifically reacted with SLE sera, but not with sera from patients with other connective tissue diseases, was identified as glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Immunoblot analysis showed that SLE sera reactive with the 37 kDa protein specifically reacted with GAPDH, as did anti-GAPDH mAbs. The purified autoantibodies to GAPDH from lupus serum showed both nuclear speckled and cytoplasmic staining patterns in immunofluorescence on Hep-2 cells. In addition, enzyme-linked immunosorbent assay (ELISA) revealed the presence of anti-GAPDH autoantibodies in 47% of lupus patients. Longitudinal analysis of the reactivity of lupus sera to PCNA complexes showed the autoimmune response to spread from GAPDH to other elements of PCNA complexes, and the presence of anti-GAPDH antibodies was significantly correlated with increased levels of serum PCNA. Taken together, these findings suggest that GAPDH interacting with PCNA in association with its cellular function is a novel autoantigen recognized by lupus sera, and that GAPDH thus plays an important role in the induction of autoimmune responses against the PCNA complex.
Asunto(s)
Autoanticuerpos/biosíntesis , Autoantígenos/inmunología , Gliceraldehído-3-Fosfato Deshidrogenasas/inmunología , Lupus Eritematoso Sistémico/inmunología , Antígeno Nuclear de Célula en Proliferación/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Enfermedades del Tejido Conjuntivo/inmunología , Humanos , Estudios Longitudinales , Ratones , Ratones Endogámicos BALB CRESUMEN
A natural serum autoantibody specific for the Thy-1 glycoprotein (anti-Thy-1 autoantibody [ATA]) is produced by B-1 cells that are positively selected by self-antigen. Here, using ATA micro kappa transgenic mice we show that cells with this B cell receptor are negatively selected during bone marrow (BM) development. In a Thy-1 null environment, BM ATA B cells progress to a normal follicular stage in spleen. However, in a self-antigen-positive environment, development is arrested at an immature stage in the spleen, concomitant with induction of CD5. Such cells are tolerant and short-lived, different from B-1. Nonetheless, ATA-positive selection was evident by self-antigen-dependent high serum ATA production, comprising approximately 90% of serum immunoglobulin M in ATA micro kappa mice. Splenectomy did not eliminate ATA production and transfer of tolerant splenic B cells did not induce it. These findings demonstrate that B-1 positive selection, resulting in the production of natural serum ATA, arises independently from the major pathway of BM B cell development and selection.