• 1 January 1979
    • journal article
    • research article
    • Vol. 36 (1), 71-79
Abstract
The peripheral blood leukocyte (PBL) response to infection with 2 species of the intestinal protozoan Eimeria [E. maxima and E. acevrulina and E. nieschultzi] shows a remarkably similar pattern in rats and chickens. Like resistance to these parasites, the PBL response to reinfection is species-specific and it coincides with the inhibition of development of the parasite and with cellular infiltration of the lamina propria. In primary infections, the numbers of PBL increased biphasically and significant changes were found in the count of polymorphonuclear cells (PMN), lymphocytes, and large mononuclear cells (LMN). A consistent pattern of 2 increases in PMN, some lymphopenia, and 2 increases in LMN was found in rats and chickens. The response to secondary infections was more rapid and much briefer, particularly in chickens in which significant changes were detected within hours of infection and consisted of an almost equal increase in PMN and in lymphocytes. This secondary response occurred only in animals challenged with the homologous species. It was not evoked by challenge with a related species which develops in approximately the same area of intestine.