ASSOCIATION OF GM ALLOTYPES WITH THE ANTIBODY-RESPONSE TO THE OUTER-MEMBRANE PROTEINS OF A COMMON UPPER RESPIRATORY-TRACT ORGANISM, MORAXELLA-CATARRHALIS

Previously, Gm allotypes have been shown to influence human serum Ig s ubclass levels as well as the Ab levels achieved after Ag stimulation. The majority of the latter studies have focused on Ab responses to po lysaccharide Ags. In this study, we have investigated the relationship between Gm allotypes and naturally occurring serum Ab levels to a bac terial protein Ag, the outer membrane proteins of a common microorgani sm, Moraxella catarrhalis. In the sera of 160 patients having chronic/ recurrent sinusitis, there was a highly significant correlation betwee n the level of specific anti-M. catarrhalis IgG3 level and certain Gm phenotypes. After additional investigation, we found that the presence of G3m(21) homozygosity correlated significantly with lower levels of Ag-specific IgG3. Specific anti-M. catarrhalis IgG3 levels were found to be independent of total serum IgG3 concentrations, and there was n o correlation between the serum level of IgG3 and any Cm phenotype. To tal Ige and IgG2 that were specific for pneumococcal cell wall polysac charide also were measured in this group of patients, and no correlati on was found between the naturally occurring IgG2 subclass levels to p neumococcal cell wall polysaccharide and the interactive effect of G2m (23) (syn: G2m(n)) and Km(1). Gm allotypes may influence Ab responses other than the anti-carbohydrate responses and, therefore, should be t aken into account when investigating IgG subclass responses to protein Ags.