Journal of Parasitology Research (Jan 2011)

Trypanosoma congolense Infections: Induced Nitric Oxide Inhibits Parasite Growth In Vivo

  • Wenfa Lu,
  • Guojian Wei,
  • Wanling Pan,
  • Henry Tabel

DOI
https://doi.org/10.1155/2011/316067
Journal volume & issue
Vol. 2011

Abstract

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Wild-type (WT) C57BL/6 mice infected intraperitoneally with 5×106 Trypanosoma congolense survive for more than 30 days. C57BL/6 mice deficient in inducible nitric oxide synthase (iNOS−/−) and infected with 103 or 5×106 parasites do not control the parasitemia and survive for only 14±7 or 6.8±0.1 days, respectively. Bloodstream trypanosomes of iNOS−/− mice infected with 5×106 T. congolense had a significantly higher ratio of organisms in the S+G2+M phases of the cell cycle than trypanosomes in WT mice. We have reported that IgM anti-VSG-mediated phagocytosis of T. congolense by macrophages inhibits nitric oxide (NO) synthesis via CR3 (CD11b/CD18). Here, we show that during the first parasitemia, but not at later stages of infection, T. congolense-infected CD11b−/− mice produce more NO and have a significantly lower parasitemia than infected WT mice. We conclude that induced NO contributes to the control of parasitemia by inhibiting the growth of the trypanosomes.