Enhancement of immune response potential of mouse lymphoid cells fractionated over insolubilized comjugated histamine columns

Spleen cells from (BALB/c C57BL/6)F₁ mice which had been immunized 7 days earlier with sheep red blood cells (SRBC) were either fractionated over columns of histamine rabbit serum albumin Sepharose beads or were untreated. Equal numbers of filtered and unfiltered cells were injected into irradiated, syngeneic recipients with SRBC. The kinetics of direct and indirect hemolytic plaque forming cells (PFC) generated by the 2 groups of transferred cells were similar. However, 4.5 more direct and 5.8 more indirect PFC were detected per unit number of spleen cells injected in the recipients of the filtered than in those of the unfiltered cells. In addition to enhanced PFC responses, spleen cell fractionation over the histamine coated beads also resulted in slight but significant increases in the numbers of nucleated cells per recipient spleen. These findings indicate that removal of cells adherent to histamine coated beads enhances the humoral immune response potential of mouse spleen cells. A similar result was obtained when histamine column fractionated thymocytes were injected together with unfractionated bone marrow cells. In contrast, no enhancing effect was observed when fractionated marrow cells were mixed with unseparated thymocytes. Fractionation of spleen cells over poly L lysine Sepharose columns, which bind mouse spleen cells and are similar in charge to histamine rabbit serum albumin Sepharose, had no detectable immunological effect on transferred spleen cells. The possibility that the columns of insolubilized conjugated histamine retain thymus derived lymphocytes which express amine receptors and function to regulate humoral immunity is considered.