Interleukin-6 is required for parasite specific response and host resistance to Trypanosoma cruzi.
Infection with Trypanosoma cruzi, the agent of Chagas' disease, results in elevated levels of interleukin-6 (IL-6) in serum and infected tissues. However, it remains unknown whether IL-6 plays a role in host defence against T. cruzi. To determine whether IL-6 underlies disease progression, we followed the time course of T. cruzi-infected mice bearing IL-6 +/+ and minus sign/minus sign genotypes, respectively. We found that IL-6 minus sign/minus sign mice were more susceptible to T. cruzi infection as they exhibited about 3-fold higher parasitaemia and died earlier than wild-type animals. Unlike what might be expected, T. cruzi-infected IL-6 minus sign/minus sign mice did not show at peak infection a decrease in the secretion of IFN-gamma, a Th1 cytokine crucial for controlling the parasite. Instead, they exhibited a much reduced splenocyte recall response to T. cruzi antigens. Our results suggest that IL-6 mediates anti-parasite protective responses against T. cruzi.
Gao
Wenda
W
Parasitology Research Center, Department of Pathology, Tufts University School of Medicine, Boston, MA 02111, USA.
Pereira
Miercio A
MA
D000818:Animals; D002455:Cell Division / Q000276:immunology; D014355:Chagas Disease / Q000276:immunology* / Q000469:parasitology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000097:blood; D015850:Interleukin-6 / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018512:Parasitemia; D014349:Trypanosoma cruzi / Q000276:immunology*
D015850:Interleukin-6; D007371:Interferon-gamma