Effect of immunostimulation on cytotoxic activity of intestinal intraepithelial lymphocytes of chickens in infectious bursal disease and Eimeria tenella infections.

In chickens, intestinal intraepithelial lymphocytes (iIELs) exhibit spontaneous natural killer (NK) cell like activity, by which they are active in the first line of defence on gut epithelial linings. In the present study, the cytotoxic activity of iIELs was found to be drastically suppressed in chickens experimentally infected with infectious bursal disease (IBD) virus at the age of 5 weeks and also in chickens experimentally infected with Eimeria tenella oocysts at the age of 8 weeks (p < 0.01). As nonspecific immunostimulation is gaining importance, immunostimulants such as immunostimulating Mycobacterium phlei (ISMP) and bone marrow culture supernatant (BMCS) were tested for their influence on the functional activity of iIELs of chickens in IBD and E. tenella infections. In chickens primed with ISMP a week prior to respective experimental infections, it was found that the cytotoxic activity of iIELs was restored (p < 0.01) in both IBD and E. tenella infections. At the same time, in chickens primed with BMCS a week prior to respective experimental infections, the cytotoxic activity of iIELs was restored to a certain extent (p < 0.01) in E. tenella but not at all in IBD infection. These results showed that application of immunostimulation helped potentiate and restore the functional activity of iIELs of chickens in IBD and E. tenella infections.