Effect of breast-feeding on immune response to BCG vaccination

The effect on BCG immunisation of feeding either formula or breast milk was assessed in Canadian Cree infants who were vaccinated either at birth or after 1 month of age. The response to BCG was measured in terms of lymphocyte blastogenesis stimulated by purified protein derivative of Mycobacterium tuberculosis. Breast-feeding significantly enhanced cell-mediated immune response to BCG vaccine given at birth, but had no significant effect if vaccine was given after 1 month. These findings were not related to maternal history of tuberculosis or BCG vaccination, and the feeding method did not influence lymphocyte stimulation by candida or streptococcal antigens.