Germinal centers are structures that promote humoral memory cell formation and affinity maturation, but the triggers for their development are not entirely clear. Activated extrafollicular B cells can form IgM-producing plasmablasts or enter a germinal center reaction and differentiate into memory or plasma cells, mostly of the IgG isotype. Vesicular stomatitis virus (VSV) induces both types of...

This study compares the ultrastructure of murine embryonal carcinoma cells, the multipotential stem cells of teratocarcinomas, with the constituents of the primordial testicular tubules in which they arise. The primordial tubules were composed of Sertoli cells and primordial germinal cells ; the former were well differentiated with Golgi membranes and well developed cisternal endoplasmic reticu...

Germinal center lymphoma is a heterogeneous human lymphoma entity. Here we report that constitutive activity of SHP2 (PTPN11) and its downstream kinase ERK is essential for the viability of germinal center lymphoma cells and disease progression. Mechanistically, SHP2/ERK inhibition impedes c-Myc transcriptional activity, which results in the repression of proliferative phenotype signatures of g...

BACKGROUND Fractalkine/CX(3)CL1, a surface chemokine, binds to CX(3)CR1 expressed by different lymphocyte subsets. Since CX(3)CL1 has been detected in the germinal centres of secondary lymphoid tissue, in this study we have investigated CX(3)CR1 expression and function in human naïve, germinal centre and memory B cells isolated from tonsil or peripheral blood. METHODOLOGY/PRINCIPAL FINDINGS W...

Germinal centers are critical for affinity maturation of antibody (Ab) responses. This process allows the production of high-efficiency neutralizing Ab that protects against virus infection and bacterial exotoxins. In germinal centers, responding B cells selectively mutate the genes that encode their receptors for antigen. This process can change Ab affinity and specificity. The mutated cells t...

Abstract T follicular helper (TFH) cells are a CD4+ cell subset that play critical role in the formation of germinal centers (GC). TFH essential to produce protective antibody responses through regulation clonal selection & differentiation into activated antibody-secreting memory B cells. is multistep process begins with presentation antigen by dendritic naïve cells, where commit lineage ex...

Lymphocyte-vascular adhesion protein-2 was recently identified as CD73. The CD73 molecule, otherwise known as ecto-5'-nucleotidase, is a lymphocyte maturation marker that is involved in intracellular signaling, and lymphocyte proliferation and activation. We now show that CD73, in addition to mediating lymphocyte binding to endothelial cells, also mediates adhesion between B cells and follicula...

Mice rendered deficient for interleukin (IL) 6 by gene targeting were evaluated for their response to T cell-dependent antigens. Antigen-specific immunoglobulin (Ig)M levels were unaffected whereas all IgG isotypes showed varying degrees of alteration. Germinal center reactions occurred but remained physically smaller in comparison to those in the wild-type mice. This concurred with the observa...

During an immune response, the affinity of antibodies that react with the antigen that triggered the response increases with time, a phenomenon known as affinity maturation. The molecular basis of affinity maturation has been partially elucidated. It involves the somatic mutation of immunoglobulin V-region genes within antigen-stimulated germinal center B cells and the subsequent selection of h...

Multiple distinct memory B-cell subsets have been identified in humans, but it remains unclear how their phenotypic diversity corresponds to the type of responses from which they originate. Especially, the contribution of germinal center-independent responses in humans remains controversial. We defined 6 memory B-cell subsets based on their antigen-experienced phenotype and differential express...