Immunoglobulins in milk from cows immunized with oral strains of Actinomyces, Prevotella, Porphyromonas, and Fusobacterium.

Immunization of pregnant cows with bacteria leads to the presence of high concentrations of specific antibodies in colostrum and milk. A total of 14 cows was immunized with single strains of heat-killed oral bacteria or pools of strains of Actinomyces, Porphyromonas, Prevotella, and Fusobacterium. Two cows were treated with adjuvant alone. The mean percentages of IgG1, IgG2, IgM, and IgA in all of the milks were 83.8, 3.8, 9.3, and 3.1, respectively. ELISA and whole cell agglutination assays demonstrated high titers in the milks from the cows immunized with either individual strains or the bacterial pools. The highest titers determined by ELISA belonged to the IgG1 isotype and in several milks were 64-fold greater than titers in milk from cows treated with adjuvant alone. The concentrations of all antibodies and the titers determined by ELISA and whole cell agglutination assays markedly decreased from the first to the sixth milkings. The functional specificity of the antibodies was demonstrated by agglutination tests against a wide range of bacteria including members of Actinomyces, Fusobacterium, Porphyromonas, Prevotella, Streptococcus, Eubacterium, Propionibacterium, Peptostreptococcus, Bacteroides, Actinobacillus, Haemophilus, Capnocytophaga, and Wolinella. Minimal cross-reactions with bacteria in other genera were observed with all of the milks. High-titer milk preparations have been obtained from immunized cows, and the capacity of the bovine antibodies to agglutinate target bacteria indicates their potential usefulness in oral passive immunization studies.

Nonspecific antibacterial factors in milk from cows immunized with human oral bacterial pathogens.

Both the immunoglobulins and non-specific antibacterial factors in milk from cows immunized with pathogenic oral bacteria have the potential to influence the oral microflora during passive immunization studies. The first six milks after calving were collected from 2 cows immunized with adjuvant and from 14 cows immunized with adjuvant and heat-killed strains of periodontopathic Actinomyces, Porphyromonas, Prevotella, and Fusobacterium. Analysis of the products from the first to the sixth milks revealed that the protein and lysozyme content decreased approximately 66 and 72%, respectively; the mean specific activity of the enzyme remained relatively constant. In contrast, the mean lactoperoxidase activity increased 2.3-fold in the second milking and increased further in the fourth and sixth milkings. The mean iron-binding activity increased 1.2-fold from the first to the second milkings and then decreased 3.6-fold through the sixth milking. Cows immunized with adjuvant alone showed similar responses. Per unit volume, the milk contained approximately 150 times less lysozyme than whole human saliva obtained from six subjects but higher concentrations of lactoperoxidase and iron-binding components. Purified bovine nonspecific factors prevented the growth of the bacteria used for immunization when bacteria were tested at concentrations similar to those found in saliva and milk. Because bovine nonspecific antibacterial factors could influence both the pathogenic target bacteria and the indigenous microflora in oral passive immunization studies with bovine immunoglobulins, the presence of these proteins should be considered.