Secretion and immunochemical properties of the trypsin inhibitor from bovine colostrum.

A trypsin inhibitor was isolated from bovine colostrum by affinity chromatography. Immunoelectrophoresis detected two immunogenic components in the isolated inhibitor, but only one of these was specific for the inhibitor; the other one was identical with an antigen present in liver, kidney, spleen, adrenal, thyroid, thymus, brain, ovarian, testicular and udder tissue and in bull seminal plasma. Using immunoabsorption and immunofluorescence it was shown that the antigens specific for the trypsin inhibitor of colostrum could be demonstrated only in the tissue of an udder that is secreting colostrum. The inhibitor is secreted by the secretory epithelium of the milk alveoli of the udder, during the period when the latter secretes colostrum. This inhibitor was not detected in the milk. Cross-reaction between antisera to colostral inhibitor and basic pancreatic inhibitor or seminal plasma inhibitors yielded negative results. Antiserum to bovine colostral inhibitor showed a positive reaction with inhibitor isolated from porcine colostrum.     

Comparative immunochemical studies of primate hemoglobins

The antigenic properties of a number of chromatographically purified primate hemoglobins were compared to those of normal human hemoglobin using a sensitive radioimmunochemical procedure. The degree of inhibition of the antigen-antibody reaction with heterologous hemoglobins appeared to be related to the structural similarity of these proteins to the normal human hemoglobin immunogen. With the exception of the baboon hemoglobin, the antigenicity of the hemoglobins paralleled the phylogeny of the primates. The gorilla and chimpanzee hemoglobins were antigenically identical to normal human hemoglobin, whereas the gibbon and orangutan hemoglobins were substantially more variable. Of the Old World monkey hemoglobins examined, the baboon produced lower inhibition values, suggesting a greater degree of structural dissimilarity than other Cercopithecoidea hemoglobins, which is compatible with a greater rate of evolutionary change occurring in this protein. Using the known amino acid sequences of human and other primate hemoglobins, we have attempted to identify antigenic determinant areas of the proteins.     

Isolation and immunochemical localization of collagenase in mouse peritoneal macrophages

Collagenase was isolated from the culture medium of thioglycollate-stimulated mouse peritoneal exudate macrophages. The macrophage collagenase activity was inhibited by goat anti-mouse bone collagenase antibody, indicating that macrophage collagenase immunologically cross-reacts with mouse bone collagenase. The enzyme was localized in mouse peritoneal macrophages by indirect immunofluorescent antibody technique. Distinct granular fluorescence was observed intracellularly in most thioglycollate-stimulated macrophages, whereas slight or no fluorescence was observed in non-stimulated control macrophages.     

Physicochemical and immunochemical studies on bovine IgA and glycoprotein-a

1. Bovine secretory IgA (SIgA) from colostrum (mol. wt. about 410,000) is composed of four alpha-chains (mol. wt. 61,000), four light chains (mol. wt. 23,000) and one molecule of glycoprotein-a (mol. wt. 70,000-86,000). The alpha-chains are antigenically and physicochemically distinct from the heavy chains of IgM, IgG1 and IgG2 while the light chains are identical to those occurring on other bovine immunoglobulins. Glycoprotein-a and bovine free secretory component are identical and the former name should be abolished. Much of this protein is covalently bonded to IgA. 2. The gel filtration behavior of serum IgA suggests it is a dimer. 3. The elution behavior of IgA and SIgA from ion-exchange columns and the solubility characteristic of SIgA in the presence of Zn2+ are similar to those of human and rabbit IgA. 4. The disc electrophoretic behavior of IgA and SIgA are distinct from IgM, dimeric IgG1, 7-S IgG and glycoprotein-a. Dimeric IgG1 (s20,w = 9.5) is abundant in colostrum and is similar in size to SIgA. 5. Bovine IgA shows physicochemical and immunochemical heterogeneity when studied by gel filtration, disc electrophoresis, immunoelectrophoresis and ultracentrifugational analyses. Lacrimal and nasal SIgA possess antigenic determinants absent on colostral SIgA.