ANTIBODY-FORMATION IN MOUSE BONE-MARROW .6. REGULATING INFLUENCE OF SPLEEN ON BONE-MARROW PLAQUE-FORMING CELL RESPONSE TO ESCHERICHIA-COLI LIPOPOLYSACCHARIDE

Abstract

Mouse bone marrow is capable of a distinct plaque-forming cell (PFC) response after i.v. immunization with the thymus-independent antigen E. coli lipopolysaccharide (LPS). During the primary and secondary response to i.v. administered LPS the spleen contained the majority of PFC until about 5 days after immunization. In the course of the reaction in the number of PFC in the bone marrow rose to a level which surpassed the level in the spleen. This paper deals with the regulating influence of the spleen on the primary and secondary anti-LPS PFC response in the bone marrow. Splenectomy prior to the 1st injection of 5 .mu.g LPS i.v. initially did not affect the bone marrow PFC response. At the 7th day after immunization the PFC response in the bone marrow fell to only 10% of the bone marrow PFC activity in sham-splenectomized mice. In contrast to the primary response no regulating influence of the spleen on the bone marrow PFC activity could be demonstrated during the secondary response. The influence of splenectomy on the appearance of B[bone marrow-derived]-memory cells in the bone marrow depended on the priming dose. The appearance of LPS-specific B-memory cells in the bone marrow was not affected by splenectomy when priming doses of LPS as high as 1 and 0.1 .mu.g were used. Splenectomy before immunization with 0.01 .mu.g LPS i.v. reduced, and splenectomy prior to immunization with 0.001 .mu.g LPS i.v. completely prevented the appearance of B-memory cells in the bone marrow.