Modulation of immune responses by bovine β‐casein

Abstract

The present study reports the influence of bovine -casein on in vitro and in vivo immune responses. Bovine -casein showed an inhibitory effect on ovine neutrophil chemotaxis but had an enhancing effect on superoxide production by neutrophils. In response to mitogenic stimulation, the proliferative response of both T and B lymphocytes was significantly enhanced by -casein. While -casein had no significant effects on IFN production by ovine blood lymphocytes, and TNF production and MHC Class II antigen expression by ovine bronchoalveolar macrophages, it enhanced IL-1 production by the macrophages. -casein also had no influence on bovine NK cell activity against a virally-infected cell line. Interestingly, -casein was found to reduce the adjuvant effect of matrix immune stimulating complexes (ISCOM) on anti-ovalbumin antibody response in mice when given intramuscularly. Taken together, the results suggest that bovine -casein had selective modulating effects in vitro on both innate and adaptive immune responses in ruminants, whereas systemic administration of -casein, that might have a depressive effect on adjuvant activity, requires further study.