Antibody formation in mouse bone marrow: II. Evidence for a memory-dependent phenomenon

Abstract

Mouse bone marrow is barely capable of plaque-forming cell (PFC) activity in a primary response to sheep red blood cells (SRBC), while PFC activity in the secondary response to SRBC can be clearly demonstrated. This phenomenon was studied by means of cell transfer experiments. T cells, which are involved in an anti-SRBC PFC response, were shown to be very scarce in normal mouse bone marrow. This is considered to be the cause of the low PFC activity in the marrow during the primary response to SRBC. In normal mouse bone marrow precursors of IgM-PFC but not of IgG- and IgA-PFC could be found. Priming with SRBC induced the appearance of IgM-, IgG-, IgA- and T-memory cells in the marrow. These B- and T-memory cells were shown to be specific for the antigen which induced their appearance. It is thought that after a second injection of SRBC the IgM-, IgG- and IgA-memory cells can differentiate with the help of the T-memory cells within the bone marrow into IgM-, IgG- and IgA-PFC respectively. The sequence of appearance of the B-memory cells in the bone marrow was shown to be IgM-IgG-IgA. Six months after the intravenous injection of SRBC, the presence of B-memory cells could be demonstrated not only in spleen and bone marrow, but also in peripheral lymph nodes, mesenteric lymph node, Peyer's patches, thymus and blood. The increase in amount of B-memory cells was most prominent in the spleen.