background: leishmania major is an intracellular parasite transmitted through the bite of the female phlebotomine sand flies. leishmania major is able to escape the host immune defense and survive within macrophages. modulation of the nf-κb (nuclear factor-kappa b) activation and suppression of the pro-inflammatory cytokines by l. major are the main evasion mechanisms that remain to be explored...

CD81 is a component of the CD19/CD21 co-receptor complex in B cells. However, the role of CD81 in B cell activation has not been clearly elucidated. Here, we demonstrate that Cd81(-/-) B cells stimulated via their B cell receptor fluxed higher intracellular-free calcium ion along with increased phosphorylation of spleen tyrosine kinase and phospholipase gamma 2. Additionally, Cd81(-/-) B cells ...

The effect of cyclosporin A (CsA), a fungal metabolite with immunosuppressive properties, on the induction of human B cell proliferation and differentiation, has been described. CsA had a selective inhibitory effect on the activation phase of the cell cycle vs. the proliferation phase following preactivation of the cells. Cell enlargement and RNA synthesis of small resting B cells triggered by ...

Antigen receptor-mediated nuclear factor κB (NF-κB) activation relies on the formation of a large multi-protein complex that contains CARMA1, BCL10, and MALT1 (CBM complex). This signalosome is pirated in the activated B-cell-like subgroup of diffuse large B-cell lymphoma (ABC DLBCL) to drive aberrant NF-κB activation, thereby promoting cell survival and propagation. Using an unbiased proteomic...

Intact (IgG class) rabbit anti-immunoglobulin antibodies are not mitogenic for mouse B cells but inhibit proliferation induced by F(ab')2 anti-Fab fragment antibodies (anti-Ig). In addition, cross-linkage of Fc and surface immunoglobulin receptors on B cells by intact anti-Ig inhibits inositol phospholipid breakdown (but not Ca2+ flux) resulting from ligation of antigen receptors. This system, ...

Discovery and use o f T cell growth factor, interleukin 2 (IL-2), 1 have made it possible to immortalize functioning T cells and have facilitated studies on the activation, function, and antigen recognition of T cells (1-3). Human and murine neoplastic T cells secreting IL-2 have been particulary useful for the isolation and molecular characterization of IL-2 (4, 5). Recent studies with success...

The recognition of antigen by membrane immunoglobulin M (mIgM) results in a complex series of signaling events in the cytoplasm leading to gene activation. Bruton’s tyrosine kinase (BTK), a member of the Tec family of tyrosine kinases, is essential for the full repertoire of IgM signals to be transduced. We examined the ability of BTK to regulate the nuclear factor (NF)k B/Rel family of transcr...

Cdc42 is a member of the Rho GTPase family that has been implicated in several cell functions including proliferation and migration, but its physiologic role needs to be dissected in each cell type. We achieved B-cell and hematopoietic stem cell deletion of Cdc42 by conditional gene targeting in mice. Deletion of Cdc42 from proB/preB-cell stage significantly blocked B-cell development at T1 and...