Investigation of bovine lacrimal and harderian glands revealed the presence of the enzyme lactoperoxidase, which was isolated and purified. A nonheme, iron-containing protein was identified at the same time. Both proteins are present in milk, mammary glands, and salivary glands. Their roles are discussed: The lactoperoxidase may be important in controlling bacterial flora.

Fifty-four strains of Neisseria gonorrhoeae were examined for their ability to be agglutinated by various lectins. Wheat germ agglutinin, ricin, soybean lectin, and peanut agglutinin agglutinated all strains tested. Dolichos biflorus, Sophora japonica, Maclura pomifera, Ulex Europaeus, Lens culinaris, Canavalia ensiformis, Phaseolus lunatus, and Bandeiraea simplicifolia BS I and BS II lectins either failed to agglutinate or agglutinated some strains but not others. Agglutination of gonococci by wheat germ agglutinin, ricin, and soybean lectin is sugar specific and most effectively inhibited by ligands known to interact with lectin combining sites. Lectin reactive groupings appear to be independent of antigenic determinants conferring Gc serogroup specificity. Interactions with wheat germ agglutinin and ricin suggest the occurrence of multiple beta-linked N-acetyl-D-glucosamine (D-GlcNAc) and beta-D-galactosyl (beta-D-Gal) units as common structural features of gonococcal cell envelope polysaccharide. Interactions with soybean agglutinin, peanut agglutinin, and Dolichos biflorus lectins suggest that alpha-N-acetyl-D-galactosamine (alpha-D-GalNAc) units and beta-D-Gal linked to GalNAc and (or) GlcNAc may also occur as structural features of the polysaccharide components of the cell envelope of some gonococci.

Plasma glutathione peroxidase (GSHPx) (glutathione: H2O2 oxidoreductase) is a unique selenoglycoprotein. Treatment of this enzyme with glycopeptidase F partially deglycosylates it and establishes the presence of N-linked sugar moieties. Antibodies raised in a rabbit against the purified enzyme from plasma were found to be specific, noninhibitory, and capable of precipitating the enzymatic activity. The antibodies precipitated greater than 90% of the GSHPx activity of normal plasma, thus indicating that the selenoenzyme is the main if not the sole GSHPx activity of plasma. The antibodies did not precipitate RBC GSHPx. A slight cross-reactivity of the antibodies was found with rat plasma GSHPx. A GSHPx activity precipitation assay of normal plasma in the presence of selenium (Se)-deficient plasma indicates that no cross-reactive protein in the Se-deficient plasma interferes with the precipitation of the GSHPx activity from normal plasma. Thus, GSHPx protein as well as activity is deficient in plasma in the absence of Se. Antibodies against GSHPx either from RBCs or from plasma were used to specifically immunoprecipitate most of the GSHPx activity from RBCs or plasma, respectively, in healthy individuals to determine the amount of Se associated with the protein. GSHPx accounts for approximately 15% of the Se in RBCs and 12% of the Se in plasma. Thus, in normal individuals, these proteins account for only a fraction of plasma and RBC Se.

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The demonstration that pneumococcal polysaccharides (1-6) and purified blood group substances (of. reference 7) are antigenic in some species and not in others and the more recent finding that dextrans are antigenic in man (8-10) but not in the rabbit (11,12) or guinea pig (12) prompted an investigation of the antigenicity of several other purified polysaccharides in human beings. Levan, apple amylopectin, maize glycogen, and two synthetic polyglucoses were tested for their ability to stimulate production of specific antibody. In a small series of individuals injected with these materials, antibody formation as evidenced by the appearance of precipitins and wheal and erythema type skin sensitivity was obtained only against levan.While levan has never been reported to be antigenic in man, Horsfall (13) and Genghof (14) noted that purified levan preparations are not antigenic when injected intravenously into rabbits in amounts from 0.15 to 15 rag. Rabbit antisera to levan, however, have been obtained by immunization with heated or formol-treated suspensions of Streptococcus salivarius and Bacillus N-9 grown in sucrose-containing media but not with these organisms grown on glucose (15). These rabbit antisera have been shown to give complement fixation and precipitation with a number of levans isolated from supernates of bacterial cultures grown on sucrose or raffinose as well as with levans synthesized by cell-free enzyme preparations (16,17). Living suspensions of Aerobacter levanicum grown on sucrose have also been employed to immunize rabbits and the antisera produced used in qualitative precipitin tests. Oligolevans were found to inhibit the levan-antilevan precipitation (18).In this investigation antiserum from an individual who showed the greatest antibody response to levan was studied by the micro-quantitative precipitin