Antigenic Heterogeneity Associated with Pilus Aggregation and Autoagglutinability in Neisseria gonorrhoeae

Abstract

A type-specific antigen of Neisseria gonorrhoeae was previously demonstrated by two-dimensional immunoelectrophoresis, and was produced by strains adapted to growth in subcutaneous chambers in guinea pigs. This antigen was also present in 'smooth' (non-autoagglutinating) variants selected directly from the first agar cultures of three clinical isolates, without chamber passage. The type-specificity of this antigen paralleled the reactions of pili in immune electron microscopy, suggesting that the type-specific antigens were pili. However, 'rough' (autoagglutinating) variants lacking this type-specific antigen were nevertheless pilated. Examination of one strain by immune electron microscopy showed that the pili of the rough variant differed antigenically from those of the smooth variant. Pili on the rough variant tended to form extensive parallel aggregates, whereas pili on the smooth variant radiated individually from the gonococci. This physical difference might relate to the behaviour of the gonococci in suspension. The significance of pilus variation in immunity to gonococcal infection is discussed.

Variant pili of autoagglutinating Neisseria gonorrhoeae

“…In addition to morphological and antigenic differences between the pili of 'smooth' and 'rough' gonococci of strain BS4 [3], the apparent M r of 'rough' pilin was 20000, as opposed to 22500 for 'smooth' pilin reported previously [1]. Similar intra-strain morphological and biochemical differences in the pili of N. gonorrhoeae strain P9 have been reported by others [9].…”

“…1) characteristic of those produced by autoag- glutinating gonococci reported earlier [3]. This treatment also reduced the risk of entrapment of aggregates of pili in the affinity chromatography column.…”

“…Antisera raised against these purified particulate antigens in both cases contained 'contaminating' antibodies, possibly directed against a pilus-associated antigen, distinct from the purified pili [1]. Previously, immune electron microscopy [3] had indicated that pili were antigenically heterogeneous among autoagglutination variants of the BS4 strain. We now report purification of 'rough' pili from an autoagglutinating ('rough') variant clone, strain BS4PR, and describe their properties and reactions with the antisera to purified pili and OMVs of strain BS4 [11.…”

Pili of Neisseria meningitidis. Analysis of structure and investigation of structural and antigenic relationships to gonococcal pili.

“…1). Penn et al (37) reported similar findings for gonococci and noted that changes in pilus aggregation were accompanied by changes in antigenic variation. Thus, the two forms of meningococcal pili seen in our electron microscopic studies and those recently reported by Greenblatt and Frasch (38) may represent meningococcal pili of distinct types.…”

Antigenic Variation of Outer Membrane Protein II in Colonial Variants of Neisseria gonorrhoeae P9

“…Recent work has shown that even in a single strain surface antigens are capable of considerable variations in vitro (Swanson, 1978; and probably in vivo (James & Swanson, 1977;McBride et al, 1981). Colonial variants of the same strain have been shown to produce pili with altered morphology and subunit molecular weight (Penn et al, 1980;Salit et al, 1980), which show differences in their attachment to epithelial cells (Lambden et al, 1981 b). However, the proteins present in the outer membrane appear capable of even greater variations.…”