Antibody formation by transferred peritoneal cells and spleen cells of mice. I. Transfer of cells from immunized non-irradiated donors to syngeneic recipients with and without antigen.

Peritoneal cells and spleen cells from LAF mice given three intraperitoneal immunizations of sheep red blood cells synthesized haemagglutinins after transfer to X-irradiated syngeneic recipients, either with or without a concomitant injection of antigen. Antibody formation by cells transferred with antigen resembled a secondary antibody response in intact animals. Haemagglutinins appeared rapidly and in high titre. Approximately 50 per cent of the antibodies were resistant to treatment with 2-mercaptoethanol. Antibody formation by cells transferred without further exposure to antigen differed in several respects. Haemagglutinin titres were lower. Throughout the period of observation, only 6–25 per cent of the antibodies formed were mercaptoethanol-resistant. In recipients injected with spleen cells, antibodies appeared rapidly, suggesting that mature antibody-forming cells had been transferred. However, in recipients injected with peritoneal cells from the same donors, antibodies were detected only after a delay of several days, which suggested that mature antibody-forming cells had not been transferred. Haemagglutinins were synthesized equally well after transfer of all types of peritoneal cells or of a fraction consisting almost entirely of lymphoid cells. Recipients of peritoneal cells from donors which had been given either one intraperitoneal immunization or three intravenous immunizations had no or only low haemagglutinin titres, in contrast to recipients of cells from donors given three intraperitoneal immunizations. These observations suggest that antibody formation in recipients of peritoneal cells only, i.e. without further stimulation by antigen, can be attributed to cells which are present in the peritoneal cavity of donors immunized repeatedly by the intraperitoneal route, but which are not part of the active antibody-synthesizing apparatus of the donors at the time of cell transfer. The development of these cells into antibody-forming cells can be detected only in an environment devoid of antigen and of mature antibody-forming cells. It is postulated that these cells are distinct from cells which respond on re-exposure to antigen.