Secretory immunoglobulin A response following peroral priming and challenge with Shigella flexneri lacking the 140-megadalton virulence plasmid

This study evaluates the ability of noninvasive Shigella spp., lacking the 140-megadalton virulence plasmid, to elicit a mucosal immunoglobulin A immune response in the intestine. For these studies, we used Shigella flexneri M4243A1 (which lacks the plasmid and is Sereny test negative) to prime and challenge three groups of rabbits perorally. Both primary and immunoglobulin A memory responses were detectable in these secretions. These findings indicate that a mucosal memory response can be primed by nonpathogenic strains of Shigella which lack the virulence plasmid.