VLA-5 in the plasma cell line, FR4ds, acts as a common regulator of VLA-4 and VLA-6 in spreading induced by fibronectin and laminin

Homing of antibody secreting cells

As activated B cells differentiate into plasma cells they complete a final series of migration steps that take them to locations where they can efficiently carry out their effector function, secreting immunoglobulin (Ig) M or IgG into circulation or releasing dimeric IgA adjacent to the epithelium for transcytosis. Recent experiments have established a key role for chemokines in directing antibody secreting cell (ASC) movement within the secondary lymphoid organs where they are generated, as well as in guiding the cells to the bone marrow or mucosal surfaces. This review discusses the chemokines involved in directing ASC movements, particularly focusing on the role of CXCR4 and CXCL12/SDF1. The function of CCR9 and CCR10 in IgA ASC homing and contributions made by integrins and lectins are also discussed.

The adhesion of anti-CD3-activated mouse T cells to syngeneic colon adenocarcinoma cells is differentially regulated by protein tyrosine kinase-, protein kinase C-, and cAMP-dependent pathways in the effector cell

The adhesion of anti-CD3-activated mouse T cells (AK-T cells) to syngeneic colon adenocarcinoma (MCA-38) cells is mediated principally through the integrin VLA-4 (alpha4beta1). We investigated the signalling pathways through which this adhesive interaction might be regulated. The protein tyrosine kinase inhibitors genistein and methyl 2,5-dihydroxycinnamate (MDHC) markedly inhibited the adhesion of AK-T cells to MCA-38 cells. Furthermore, pretreatment of the AK-T cells alone (but not the MCA-38 targets) with MDHC inhibited adhesion to a comparable extent as when MDHC was present during the assay. Calphostin C, an inhibitor of protein kinase C, also inhibited the adhesion of AK-T cells to MCA-38 monolayers. However, the phosphatidylinositol 3-kinase inhibitor wortmannin failed to alter AK-T cell adhesion to MCA-38 tumour cells. Inhibition of protein kinase A with the Rp diastereomer of adenosine cyclic 3',5'-phosphorothioate had no effect on adhesion, but the adenylyl cyclase activator forskolin and the cell-permeable cAMP analogues 8-Br-cAMP and dibutyryl-cAMP significantly suppressed adhesion. Pretreatment of AK-T cells alone with forskolin also inhibited adhesion. The adhesion of AK-T cells to MCA-38 tumour targets is therefore promoted by protein tyrosine kinases and protein kinase C, but inhibited by cAMP-dependent pathways, and the predominant location of the regulatory pathways is within the effector cell.