Epidemiological survey of serum titers from adults against various Gram-negative bacterial V-antigens

Abstract

AbstractThe V-antigen, a virulence-associated protein, was first identified inYersinia pestismore than half a century ago. Since then, other V-antigen homologs and orthologs have been discovered and are now considered vital molecules for the toxic effects mediated by the type III secretion system in infections caused by various pathogenic Gram-negative bacteria. After purifying recombinant V-antigen proteins including PcrV fromPseudomonas aeruginosa, LcrV fromYersinia, LssV fromPhotorhabdus luminescens, AcrV fromAeromonas salmonicida, and VcrV fromVibrio parahaemolyticus, we developed an enzyme-linked immunoabsorbent assay to measure titers against each V-antigen in the sera collected from 186 adult volunteers. Different titer-specific correlation levels were determined for the five V-antigens. The anti-LcrV and anti-AcrV titers shared the highest correlation with each other, with a correlation coefficient of 0.84. The next highest correlation coefficient was between anti-AcrV and anti-VcrV titers at 0.79, while the lowest correlation was found between anti-LcrV and anti-VcrV titers, which were still higher than 0.7 Sera from mice immunized with one of the five recombinant V-antigens displayed cross-antigenicity with some of the other four V-antigens, supporting the results from the human sera. Thus, the serum anti-V-antigen titer measurement system could potentially be used for epidemiological investigations on various pathogenic Gram-negative bacteria.