Immunoglobulin classes in genital secretions of mycoplasma-infected and normal heifers.

Immunoglobulin levels were studied in the genital secretions of seven heifers which had been bred to a bull infected with Mycoplasma agalactiae var. bovis and three heifers bred to a noninfected bull. The median immunoglobulin G (IgG)/IgA ratio ratio for vaginal secretions was 0.7, for cervical secretions 21.9, and for uterine secretions 13.0. This indicated that IgA was the mahor immunoglobilin class in the most superficial portion of the reproductive tract and that IgG was the major class in secretions of the deeper tract. The response to infection was studied by comparing animals infected with mycoplasma and noninfected controls. The IgG/IgA ratios were significantly lower in infected animals than in controls, apparently due to high IgA values in infected animals. Low mycoplasmal agglutinin titers were detected in secretions of three of the infected animals, but there appeared to be no relationship between agglutinin titers and histopathological lesions or between agglutinin titers and IgG/IgA ratios in this group of animals.