C.parvum- and bacillus calmette and guerin-induced granuloma formation in CD4/CD8 knockout mice

Abstract

Granuloma formation is a T-cell dependent inflammatory response that is important to the host defense against some bacteria. The purpose of this study is to examine the role of CD4 and CDS molecules in the pathogenesis of C.parvum- and BCG-induced granulomas using CD4/CD8 KO mice. CD4/CD8 KO mice developed a greater granulomatous response to heat-killed C.paryum and heat-killed BCG than did control mice. Thus, surprisingly, granuloma formation is not dependent upon the presence of CD4 and CD8. On the other hand, CD4/CD8 KO mice challenged with live BCG had fewer and smaller granulomas and a greater bacterial load than control mice. The absence of CD4 and CDS therefore impaired the host defense against infection with BCG. αβ T-cells were present in the granulomas of both CD4/CD8 KO and control mice to similar extent. In conclusion, CD4 and CDS are not essential to the granulomatous response induced by C.parvum and BCG, but contribute to the host defense against live BCG infection, and αβ T-cells can take part to granuloma formation even if devoid of CD4 and CDS.