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.
Bibliographical noteFunding Information:
Received December 2, 1991. Accepted March 10, 1992. 'This research was supported in part by Grant 1 B O DE98489 from the National Institute of Dental Research, National Institutes of Health, Bethesda, MD 20892. 2Depmbmmt of Oral Biochemistry, Tohoku University, Sendai, Japan. 3T0 whom correspondence and reprint requests should be addressed.
- antibacterial factors
- bovine milk
- oral bacteria