Antibodies to the Pentapeptide Subunit of Peptidoglycan in Human Sera

Muramic acid in human peripheral blood leucocytes in different age groups

“…Muramic acid was also observed in a carbohydrate fraction of normal human spleen using colorimetric, enzymatic and high-pressure-liquid chromatography analysis [7] and in splenic macrophages of rats utilizing monoclonal antibodies against intestinal peptidoglycan-polysaccharide [8]. Similarly, the presence of PG-specific antibodies in normal human sera suggests systemic absorption of bacterial cell walls [9].…”

“…Alternatively, presence of muramic acid in the peripheral blood leucocytes could inversely reflect the level of circulating PGspecific antibodies and removal of immunocomplexies. Indeed, clear age dependency of PG-specific antibodies has been reported: antibodies against the pentapeptide subunit of PG in healthy children increased significantly with age from 6 months to 15 years [9]. In healthy adults PG antibodies were observed frequently in the younger population and considerably less often in advanced age (70 years or older) [10].…”