The effect of lectins on the migration of lymphocytes in vivo

The aim of the present study was to determine whether the cell-surface structures involved in the migration of lymphocytes to lymphoid organs are related to the structures on lymphocytes which interact with plant lectins. Cells from the spleen, lymph nodes, thymus, and bone marrow of A and C3H mice strains were labeled with ⁵¹Cr, exposed in vitro to various concentrations of lectins, and injected intravenously to syngeneic recipients. Exposure of lymphocytes of various sources to Con A inhibited their migration to lymph nodes to a significantly greater extent than their migration to the spleen. Various concentrations of PHA inhibited the migration of lymphocytes to the spleen and lymph nodes to a similar degree. The migration of thymus cells was affected by lower concentrations of either Con A or PHA than the migration of the other cell types. Fucose-binding protein and wheat germ agglutinin failed to affect lymphocyte migration. The inhibitory effect of Con A could be abrogated by α-methyl-mannopyranoside added either simultaneously with Con A or following exposure of the cells to Con A. In contrast, the inhibitory effect of PHA could not be abolished by the addition of N-acetyl-galactosamine. Secondary transfer experiments with lymphocytes localizing in the spleen and lymph nodes of primary hosts indicate that Con A does not eliminate a subpopulation of lymph-node-seeking lymphocytes, but rather interferes specifically with the process involved in the localization of lymphocytes to lymph nodes.