Immunoglobulins in Mammary Secretions

Milk contains a range of factors which contribute to the protection of the neonate and the mammary gland from disease. Antibodies are an important component of the disease resistance function of mammary secretions. Unlike most other major organic components found in milk, immunoglobulins (Ig) are not synthesized by the mammary epithelial cells. Considerable diversity exists among mammalian species in the transport of Ig from mother to neonate, as well as in the implications of that transport. This chapter will discuss Ig found in mammary secretions in the context of their diversity of structure, origin, transfer and function. A number of recent reviews can provide more detailed discussions of milk Ig and immuno- cytes (Telemo and Hanson, 1996; Butler, 1998, 1999), mucosal immunity (Chernishov and Slukvin, 1990; Brandtzaeg et al., 1991; Cummins and Thompson, 1997), mammary gland immunobiology (Lee et al., 1992; Sordillo et al., 1997) and evolution of immunologie functions of the mammary gland (Goldman et al., 1998). The disease resistance function of Ig typically occurs in concert with a range of protective factors and several other reviews address the spectrum of anti-infective components of milk (Goldman, 1993; Xanthou et al., 1995; Xanthou, 1998; Goldman and Ogra, 1999).