Effect of stromal mechanocytes of hematopoietic organs on in vitro formation of antibody producing cells

: Cultured rabbit fibroblasts of bone marrow, thymus and spleen origin were added in spleen cell cultures in which the primary antibody response to SRBC was induced. Bone marrow fibroblasts caused strong inhibition of the response; thymus fibroblasts stimulated antibody formation; spleen fibroblasts inhibited the response when added in large amounts otherwise they produced no effect. The stimulation of antibody forming cell response by thymus fibroblasts proved independent of whether fibroblasts were irradiated or not. Bone marrow fibroblasts exhibited suppressive effect on the response predominantly during initial stages of antibody induction. All the 3 types of fibroblasts did not influence cell viability in spleen cells cultures, and were much more effective on addition to cultures of A-deficient spleen cells as compared to full spleen cells.