Antigen-independent regulation of cytoplasmic calcium in B cells with a 12-kDa B-cell growth factor and anti-CD19.

AUTOR(ES)

Ledbetter, J A

RESUMO

Increases in cytoplasmic free calcium ([Ca2+]i) can be induced in resting B cells either by a low molecular weight (12-kDa) B-cell growth factor (LMW-BCGF) or by crosslinking the B-cell antigen CD19 with monoclonal antibody (mAb). LMW-BCGF causes a slow [Ca2+]i increase in peripheral blood and tonsillar B cells but has no effect on [Ca2+]i in resting T cells. B-cell [Ca2+]i responses mediated by anti-surface immunoglobulin (sIg) or anti-CD19 are potentiated by LMW-BCGF, but anti-sIg and anti-CD19 do not show additive [Ca2+]i responses. LMW-BCGF- and anti-CD19-induced [Ca2+]i signals are similar to the sIgM or sIgD-mediated signals in that they are inhibited by prior treatment with phorbol 12-myristate 13-acetate. However, LMW-BCGF- and CD19-mediated signals do not depend on the expression of sIg, since they were also observed on sIg-B-cell precursor acute lymphoblastic leukemia (ALL) cells. Both anti-CD19 and LMW-BCGF stimulated in vitro colony formation by ALL cells and showed additive effects when used together. [Ca2+]i responses to LMW-BCGF or CD19 cross-linking were also evident on certain pre-B-cell and lymphoma B-cell lines.

Documentos Relacionados

• Tissue-specific expression of the human CD19 gene in transgenic mice inhibits antigen-independent B-lymphocyte development.
• Antigen-independent memory CD8 T cells do not develop during chronic viral infection
• B-cell growth factor: distinction from T-cell growth factor and B-cell maturation factor.
• Interleukin-12 is sufficient to promote antigen-independent interferon-γ production by CD8 T cells in old mice
• Molecular analysis of antigen-independent adhesion forces between T and B lymphocytes.