Specific milk immune response of rural and urban Guatemalan women to oral immunization with a food protein.

Forty-nine lactating women from Guatemala, 18 from a rural community and 31 from Guatemala City, were immunized orally with a protein extract from Vigna sinensis. Oral vaccination during the 1st week postpartum induced the appearance of short-lived, specific antibodies in milk in 59% of the subjects. No differences in rates of lactoconvertion were found either between socioeconomic groups or between malnourished and well-nourished women.