Immune response of the mammary gland and role of immunization in mastitis control.

It has been mentioned that IgG1 is the major secretory immunoglobulin class in mammary gland secretions; in addition, most immunoglobulins of all classes in these secretions are of humoral origin. A transport mechanism selectively favors IgG1. A lesser amount of immunoglobulin is produced locally in the gland, this local contribution apparently increasing after antigenic stimulation. Therefore, systemic and local stimulation would be likely to contribute to the presence of specific antibodies in secretions. The role of cellular immune phenomena as it relates to the mammary gland has not been determined. There is evidence for the influence of phagocytic cells in the mammary gland. Published reports have established that a state of heightened resistance to mammary gland infection can be induced. Research workers have clearly shown that immunized animals resist challenge exposure to infection to a greater degree than do nonimmunized animals. This resistance, being not absolute, causes reluctance to use the term immune. It is apparent that reexamination must be made of the correct conditions, i.e., effective antigenic preparation, proper inoculation route, dose, and duration necessary to stimulate an immune response in the mammary gland.