Effect of a proline-rich polypeptide on IgG level in Chickens.

We have previously shown that a proline-rich polypeptide (PRP) from ovine colostrum expresses an immunoregulatory activity in mice on humoral and cellular immune response. The results presented in this communication show that PRP also modulates the immune response in chickens. PRP administered to the chickens in portions before, simultaneously or after the antigen, stimulated the antibody production. The enhancement of the immune response was also observed when a single dose was injected to the chicken before or simultaneously with the antigen. On the other hand, the single doses of PRP applied to the chickens after the immunization caused an inhibition of the production of antibodies.