Isolation of a lipopolysaccharide mutant of Neisseria gonorrhoeae: an analysis of the antigenic and biologic difference.

Analysis of the surface constituents of a pyocin 611 131-resistant variant of strain no. JW-31 of Neisseria gonorrhoeae revealed substantial differences in the lipopolysaccharide (LPS) but not changes in the auxotype or outer-membrane proteins. Immunodiffusion and an enzyme-linked immunosorbent assay showed that the variant strain (no. JW-31R) lost both the LPS serotype and the variable antigens while retaining at least a portion of the common determinant. The use of monoclonal antibody indicated that LPSs from strain no. JW-31R and pyocin 611 131-resistant strains of other LPS serotypes lack a D-galactosaminyl-D-galactopyranosyl-D-glucose moiety. The LPS-derived polysaccharide from strain no. JW-31 binds to wheat-germ lectin in precipitin and inhibition systems, whereas the JW-31R polysaccharide exhibits a markedly reduced affinity. In the presence of normal human serum, 99% of strain no. JW-31R was killed within 20 min and strain no. JW-31 was not.