Cells involved in the immune response, IX. Depletion from the normal rabbit bone marrow of antigen-reactive cells directed toward human peripheral leukocytes

Immunoglobulin receptors on human leucocytes. 3. Comparative study of human bone marrow and blood B cells: role of IgM receptors

A comparative study of B cells present in human bone marrow and blood was performed. In both compartments the cells carrying the Ig receptors were found to be small mononuclear cells. Predominance of IgM receptors was found on bone marrow cells whereas Ig receptors present on peripheral blood cells were predominantly of the IgG class. Bone marrow lymphoid cells of non-sensitized donors were capable of binding a primary antigen, keyhole limpet haemocyanin (KLH) and could be retained on glass bead columns coated with either KLH or with goat anti-human IgM antiserum but not with anti-IgG. Whereas bone marrow cells of donors immunized with KLH 16–27 days earlier lacked KLH reactive cells, the latter cells could be demonstrated in the blood. It is concluded that human bone marrow B cells carrying IgM receptors are essential for the early antigen recognition step following which recruitment of these cells into the circulation takes place.

Cells involved in cell-mediated and transplantation immunity in the rabbit. I. The noninvolvement of the bone marrow antigen reactive cell in the transplant rejection reaction

Rabbits were subjected to 800 r total body irradiation to render them immunoincopetent with respect to the humoral immune response. These rabbits were, however, only slightly less capable of rejecting skin allografts than nonirradiated rabbits. Furthermore, the administration of normal or specifically "primed" bone marrow cells (bone marrow obtained from a rabbit injected one to two days previously with the spleen cells obtained from the prospective skin donor) did not enhance or inhibit the graft rejection reaction. It is concluded that the cells mediating the humoral immune response are different from those mediating the cellular immune response.