Salmonella Vectors Excel At Priming Immune Response.(Brief Article)

2001 DEC 19 - (NewsRx.com & NewsRx.net) -- by Sonia Nichols, senior medical writer - Settling the argument that preexisting immunity may override the effects of certain antigen vectors, researchers at the University of Alabama contend Salmonella enterica serovar Typhimurium is a good choice for delivering and priming the immune response system to some antigens.

"Contradictory reports have described the effect of preexisting immunity to the antigen delivery vehicle," said C. Jespersgaard, University of Alabama, Birmingham. "We decided to examine this discrepancy by studying the effect of immunizing mice by the intranasal route with Salmonella expressing an insoluble protein and to study the ability to augment recall responses by boosting with either Salmonella-expressed protein or purified soluble protein alone."

First, Jespersgaard developed a recombinant construct composed of the Salmonella vector and the insoluble glucan-binding domain (GLU) of glucosyltransferase, (GTF), a particularly virulent antigen.

The construct was administered to several mice that almost three and a half weeks later received booster doses of Salmonella-expressing GLU construct or a purified GLU polypeptide. Several other control mice received intranasal doses of saline throughout the entire study.

All mice receiving booster doses of construct or polypeptide developed significant levels of antibodies to GLU (anti-GLU serum immunoglobulin) by the 18th week of the study, with those receiving purified GLU polyprotein expressing the highest antibody levels, according to ...