Anchorage and lymphocyte function. Acquisition of spontaneous motile behaviour by human blood lymphocytes and its modulation by concanavalin A.

The majority of splenic lymphocytes were motile, showing lamellipodial activity almost immediately after purification. In contrast, fresh blood lymphocytes were non-motile and maintained their spherical suspension morphology. The number of motile blood lymphocytes increased markedly during a 2-day in vitro culture period. This increase was enhanced by high cell density and required a metabolically active cell with protein synthesis but not exogenous mitogens. The spontaneous development of motility in different subpopulations of blood lymphocytes was analysed by means of monoclonal antibodies. The results indicated that cells which were motile immediately after purification were almost exclusively non-T lymphocytes. Lymphocytes which became motile during in vitro culture included both T and non-T cells. Substrate adhesion mediated by concanavalin A (Con A) changed the morphology of motile T lymphocytes and instead of being polar, the cells flattened over the substratum and acquired a non-polar shape. Furthermore, the morphogenetic response induced by Con A-mediated substrate adhesion appeared to distinguish T and non-T lymphocytes. Thus, the length of the cell perimeter showing lamellar activity was greater in T than in non-T lymphocytes, and the degree of polarity was greater in non-T (with and without B-cell markers) than in T lymphocytes.