BACKGROUND IMMUNOGLOBULIN-SECRETING CELLS SPECIFIC FOR INTESTINAL PEPTIDOGLYCAN-POLYSACCHARIDES IN MICE

Natural antibodies to soluble peptidoglycan-polysaccharide complexes ( PPC) from the human intestinal flora have been found in mammalian sera . In this study the occurrence and frequency of PPC-specific immunoglo bulin-secreting cells (anti-PPC Ig-SC) were determined in lymphoid org ans of normal (C57BL x CBA)F1 mice. One out of 100 IgM-SC in the splee n and Peyer's patches was found to be specific for PPC. In the small i ntestine a small number of anti-PPC IgA-SC were present probably respo nsible for IgA secretion in the gut lumen since very low serum concent rations anti-PPC IgA were found. Anti-PPC IgG-SC were not detected, al though some anti-PPC IgG was found in the serum. It is concluded that the spleen is the major lymphoid organ responsible for the production of natural antibodies to PPC.