Immunocyte populations in the mammary gland of the rat at different stages of pregnancy and lactation.

Immunocyte populations of apparently normal rat mammary glands were examined at different stages of lactation using immunofluorescence techniques. IgA-and IgG-containing cells were present before parturition; IgA-containing cells were numerous than IgG- or IgM-containing cells during the entire period from pregnancy through parturition and lactation to involution.