Effects of selenium deficiency in the development of trypanosomes and humoral immune responses in mice infected with Trypanosoma musculi

Summary.

The selenium-deficient mouse-trypanosome system was used to study the effects of selenium deficiency in Swiss Webster mice infected with Trypanosoma musculi. In selenium-deficient mice, a low parasitemia was observed and infection was cleared by day 16 post-inoculation (PI), whereas control mice sustained the parasitemia until day 24 PI. There were no significant differences in size variability of the trypanosomes; however the range of variability in the length of parasites differed significantly between the three groups. In comparison to mice on complete or pair-fed diets, the selenium-deficient mice produced lower concentrations of IgG₁, IgG_2b, IgG₃, and IgM. The levels of IgG_2a and IgA were lower than normal controls. The results of the present study indicated that there was a severe depression in primary and secondary antibody responses to sheep red blood cells in all inoculated mice. However, these responses were significantly less depressed in selenium-deficient mice.