Adjuvant Activities in Production of Reaginic Antibody by Bacterial Cell Wall Peptidoglycan or Synthetic N -Acetylmuramyl Dipeptides in Mice

Abstract

This paper is concerned with the adjuvant activity in stimulatory immunoglobulin E production against ovalbumin (OA) by bacterial cell walls, cell wall peptidoglycan (PG), and their PG fragments and synthetic N -acetylmuramyl (MurNAc) dipeptides in A/J mice. A PG isolated from Streptococcus pyogenes , PG subunit polymer and dimer obtained from Staphylococcus epidermidis , and water-soluble fragments of cell walls or PG prepared from Nocardia corynebacteriodes and Streptomyces gardneri were found to enhance both the primary and secondary responses of anti-OA immunoglobulin E antibody production. It was suggested that the PG portion, either intact or highly degraded, was capable of enhancing the immunoglobulin E antibody production, and there was no need for the non-PG moiety or intactness of PG structure for the adjuvant activity. This finding was confirmed and extended by the use of synthetic MurNAc dipeptides. Among eight MurNAc dipeptides tested, MurNAc- l -Ala- d -isoGln, MurNAc- l -Ala- d -Gln, MurNAc- l -Ala- d -Glu, and MurNAc- l -Ser- d -isoGln were found active as an adjuvant in the stimulation of the primary and secondary reaginic anti-OA antibody production in a similar way to the cell wall PG and their fragments. None of the synthetic MurNAc- l -Ala- l -isoGln, MurNAc- l -Ala- l -Gln, MurNAc- l -Ala- l -Glu, and MurNAc- l -Ala- d -isoAsn, on the other hand, stimulated the anti-OA immunoglobulin E antibody production in either primary or secondary response, indicating the importance for the adjuvancy in immunoglobulin E production of the configuration of the glutamic acid residues adjacent to the l -Ala (or l -Ser) in muramyl dipeptides.