Heterogeneity of B-cells.

Two rat monoclonal antibodies, NIM-R2 and NIM-R3, were prepared that only recognize B-cells in murine secondary lymphoid tissues. Both showed differential reactivity in that they reacted most strongly with nonoverlapping populations of B-cells. They also reacted differentially with some cells of the primary lymphoid tissue, recognizing 90-95% of bone marrow cells, again in a nonoverlapping manner and with NIM-R2 accounting for twice as many cells as NIM-R3. The antibody NIM-R2, but not NIM-R3, also recognized thymocytes and red blood cells. The determinant recognized by NIM-R2 is of interest because it fluctuates at four defined stages of B-cell development: pre-B to immature B, activation of mature B, differentiation of memory cells, and differentiation of antibody-secreting cells. Particularly noteworthy was the differential reactivity of NIM-R2 with virgin and memory B-cells. Those cells that stained strongly with the antibody gave excellent primary responses, but were unable to transfer secondary responses, whereas weakly stained B-cells transferred memory, but could not generate primary antibody responses in vitro. Thus NIM-R2 recognized a cell-surface determinant that presumably decreases in density as primary B-cells differentiate into memory B-cells. A survey of sIg, I-A, Fc receptors, and major glycoproteins of B-cells from spleen, Peyer's patches, mesenteric lymph nodes, and peripheral lymph nodes failed to reveal any major differences between the cells from these different lymphoid organs.