Immunochemistry of Group A and Inaba C Antigen Factors Constituting the O Antigen of Ol Vibrio cholerae

Abstract

Serological cross‐reactivity among intact lipopolysaccharides (LPS) from Ol Vibrio cholerae Inaba O‐form (Inaba), Yersinia enterocolitica 09 (09), non‐Ol V cholerae serogroup Hakata (Hakata) and Vibrio bio‐serogroup 1875 Variant (1875 Variant) (all of which share Inaba antigen factor C), as well as a total of six kinds of chemically modified LPS (three from 09 and three from Inaba) was demonstrated by passive hemolysis and passive hemolysis inhibition by using these LPS as antigen for sensitizing sheep red blood cells and as inhibitor. These intact as well as chemically modified LPS contained, in their O polysaccharide chain, α:(1→2)‐linked linear perosamine (4‐amino‐4,6‐dideoxy‐D‐manno‐pyra‐nose) homopolymers with different Af‐acyl groups: their acyl groups comprise 3‐deoxy‐L‐gfycero‐tetronyl (Inaba LPS), formyl (09 LPS), 3‐hydroxypropionyl (1875 Variant LPS), acetyl (Hakata LPS and artificially introduced into Inaba and 09 LPS), propionyl and butyryl (both artificially introduced into Inaba and 09 LPS) groups. N‐Deacylation of the a(l→2)‐linked Af‐(3‐deoxy‐L‐gfycero‐tetronyl)perosarnine ho‐mopolymer of Inaba and the JV‐formyl one of 09 LPS resulted in virtual elimination of their serological reactivity with both homologous and heterologous antisera. Furthermore, when the resultant NH2 groups of the N‐deacylated perosamine homopolymers of both LPS were 7V‐acylated with acetyl, propionyl or butyryl groups, they markedly recovered both of their serological reactivities. These results are compatible with the interpretation that the Inaba antigen factor C possessed by the four bacteria is substantially related to the common presence of Af‐acyl groups, regardless of their identity, residing in the perosamine residues constituting the O polysaccharide chain of their LPS. It was also indicated that the group antigen factor A of Ol V. cholerae is substantially related to the 3‐deoxy‐L‐glycero ‐tetronyl groups residing in the perosamine homopolymer of Inaba LPS. Copyright © 1995, Wiley Blackwell. All rights reserved