The enhancing effect of bone marrow cells on the primary immune response of the isolated perfused spleen.

The addition of bone marrow cells or peripheral lymphocytes to the isolated pig spleen markedly enhanced the primary antibody response after 3-day perfusion and antigenic challenge in vitro. The splenic preparation without added cells or with the addition of marrow cells to an irradiated spleen gave a limited response. Contributory evidence is provided that at least two distinct cell types are needed for antibody production. For optimal antibody response by an isolated perfused spleen, marrow cells or peripheral lymphocytes should be added to the system.