Effects of prolonged bracken fern feeding and enzootic bovine haematuria on immune system in hill cows

The objective of this study is to assess the immunomodulatory role of prolonged feeding of bracken fern and spontaneous cases of enzootic bovine haematuria (EBH) in hill cows. To assess the humoral immune response in bracken fern fed and EBH affected cows, antibody level against Brucella abortus strain-19, (on day one 5 ml, S/C injection) was measured by tube agglutination test on 21st day. Cell-mediated immune response was measured by 2–4, dinitrochlorobenzene (DNCB) test in which, 2% DNCB was topically sprayed on two specific measured areas of neck for 3 days and challenged on opposite side on 14th day. Subsequently, during challenge, skin thickness was measured and biopsies were collected for histopathological evaluation. For in vitro studies, peripheral blood lymphocytes were isolated and lymphocyte transformation test was carried out by 3-[4, 5,-dimethyl thiazol-2-yl]-2, 5-diphenyl (MTT) assay. Humoral immune response against B. abortus declined in fern fed and EBH affected experimental animals than controls. DNCB test revealed that fern fed and EBH affected cows had intense delayed type hypersensitivity reactions on 24th h. post challenge. Lymphocyte proliferation assay showed significant proliferative response at concentration of 5 μl. Con-A and 10? μl. PHA in these animals than controls. Prolonged bracken fern feeding and spontaneous cases of EBH led to decline in humoral immune response and enhancement in cell-mediated immune response.