Doubling Time of Mouse Spleen Cells during the Latent and Log Phases of Primary Antibody Response

Abstract

Summary Cellular events were followed during the latent and log phases of primary antibody response by culturing spleen cells in 0.1-µ diffusion chambers. The results show that the decrease in T2 of the total cells and the increase in the number of mitotic cells after antigenic stimulation are reflections mainly of proliferative activities of blast and plasma cells. Estimates of the ratio, S:GT, indicate that after antigenic stimulation a significant increase was detected only among the immature plasma cells and lymphocytes. This would indicate that either the S period is prolonged or the GT decreased. Of interest also was the fact that the ratio for the reticulum-blast cells was 0.9 (68/75). This would indicate that the G1 period of these cells is very short. These results indicate that one is confronted with at least three variables when he is dealing with an intermediate cell compartment of a differentiation process in an immune response, i.e., the variable cell cycle dependent upon the stimulant and the input and output rates. Taking into consideration the cell compartment size, the T2, T1/2, and S:GT of each cell compartment, we can conclude that the terminal plasma cells are the end state of differentiation of reticulum-blast cells, suggesting that if other unique somatic cells can give rise to terminal plasma cells they must do so by feeding into the primary cell compartment.