The Distribution of Immunoglobulin-containing Cells in the Goat Mammary Gland: A Morphometric and Immunohistochemical Study

The distribution of immunoglobulin (Ig)-containing cells in the mammary gland of the goat was studied at different stages of the reproductive cycle using immunohistochemical techniques. Generally, Ig-containing plasma cells (IgA, IgG and IgM) in the mammary gland were abundant during pregnancy, increase in number after parturition and gradually decrease in number, especially in the post weaning period. IgA-containing cells were the predominant cell type among the plasma cells throughout the reproductive cycle. Their number increased at late pregnancy, being maximum at the colostrum period and decreased thereafter. IgG- and IgM-containing plasma cells were fewer at all stages of the reproductive cycle; the former were slightly more than the latter. Both types of cells followed a distribution pattern similar to that shown by IgA-containing cells. The rich existence of plasma cells at late pregnancy and colostrum period suggests that their main role is transfer of passive immunity to the neonates rather protection of the mammary gland.