Specific antibodies to cholera toxin in rabbit milk are protective against Vibrio cholerae-induced intestinal secretion.

Breast feeding helps to protect the nursing infant against infectious diarrhoeas, but the relative importance of antibodies compared with other components present in milk is unsettled. In order to aid in resolving this issue we evaluated the ability of milk, collected from rabbits not immunized or immunized enterally during pregnancy with toxinogenic, live Vibrio cholerae, to inhibit water secretion induced by V. cholerae in rat ileal loops. Non-immune milk was not inhibitory, whereas immune milk was. The inhibitory component of the immune milk was immunoglobulin by virtue of its molecular weight and absorption by an anti-rat immunoglobulin immunosorbent. In addition, the inhibitory antibodies were principally antibodies to cholera toxin because they could be removed from the milk by a cholera toxin immunosorbent but were only partially removed by incubation with whole V. cholerae. Thus, in rabbit milk, we could implicate specific antibodies in protection against intestinal water secretion induced by V. cholerae.