Established T(H1) granulomatous responses induced by active Mycobacterium avium infection switch to T(H2) following challenge with Schistosoma mansoni.
Mycobacterium avium established a systemic infection with granulomatous inflammation in mice. Mice chronically infected with M. avium and subsequently co-infected with Schistosoma mansoni developed additional, but morphologically distinct, hepatic granulomas. Schistosome eggs were not deposited in the spleen, and splenic granulomas in co-infected mice contained mycobacteria. In complete contrast to the T(H1) cytokine pattern observed with granuloma lymphocytes from M. avium-infected mice, granuloma lymphocytes from co-infected mice stimulated with PPD elaborated IL-4, but not IFN-gamma. Furthermore, mycobacterial granulomas in concurrently infected mice contained large numbers of eosinophils, a feature never seen in granulomas of M. avium-infected mice. Serum IgG1 and IgE levels in concurrently infected mice were significantly higher, but IgG2a levels significantly lower, than those in M. avium-infected mice, further evidence that the T(H1) component induced by M. avium is modulated subsequent to co-infection with S. mansoni. The dominance of the T(H2) response observed in this model could have clinical implications in areas where parasites and mycobacteria co-exist.
Sacco
Randy
R
Department of Pathology, University of Iowa College of Medicine, Iowa City 52242, USA. rsacco@nadc.ars.usda.gov
Hagen
Michael
M
Sandor
Matyas
M
Weinstock
Joel V
JV
Lynch
Richard G
RG
D000818:Animals; D005260:Female; D006099:Granuloma / Q000209:etiology* / Q000276:immunology; D007073:Immunoglobulin E / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D015847:Interleukin-4 / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D009162:Mycobacterium avium / Q000276:immunology*; D012555:Schistosomiasis mansoni / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*; D014376:Tuberculosis / Q000276:immunology* / Q000473:pathology
D007074:Immunoglobulin G; D015847:Interleukin-4; D007073:Immunoglobulin E