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Biomedical subjects

P A Small

Publications and source records attributed to P A Small.

At least 73 records · Page 4Linked to original sources
PubMed1972

Adherence inhibition of Streptococcus mutans: an assay reflecting a possible role of antibody in dental caries prophylaxis.

Adherence of cariogenic streptococci to the smooth surfaces of teeth has been shown to lead to plaque formation and ultimately to caries production. This adherence can be reproduced in vitro and requires sucrose in the growth media. The work reported here describes the development of an assay based on the ability of immune rabbit serum to inhibit adherence of Streptococcus mutans 6715 to glass surfaces. Rabbits were immunized with Formalin-killed whole bacteria. Sera were titered for adherence inhibition and bacterial agglutination. The former assay was found to be dependent upon immunoglobulin G (IgG) antibody, whereas the latter detected either IgG or IgM antibodies. These two assays appeared to detect different antigens. It was hypothesized that the adherence inhibition assay detects antibody directed against an enzyme, perhaps dextransucrase, responsible for dextran synthesis, since immune serum was found to inhibit incorporation of radiolabel from (14)C-sucrose into cell wall extract. The adherence inhibition assay has potential application for study of other cariogenic bacteria. Studies are being pursued in the hope that this assay may lead to a means of control of dental caries.

Adsorption↗
PubMed1970

Phylogeny of immunoglobulin structure and function. V. Valences and association constants of teleost antibodies to a haptenic determinant.

The giant grouper, Epinephelus itaira, was shown to synthesize 16 and 6.4S antibodies specific for the dinitrophenyl determinant (DNP). Sera obtained at various intervals between 1 month and 2 yr after initial immunization contained both species of antibody; no temporal synthesis was evident. Equilibrium dialysis studies employing epsilon-dinitrophenyl-amino caproic acid were conducted with purified grouper antibodies specific for DNP. The 16S antibody preparations obtained at 1 and 2 months of immunization showed heterogeneity of hapten binding indicative of two populations of combining sites. One-half of these sites (an average of four sites per 16S molecule) exhibited an average intrinsic association constant (K(o)) of approximately 10(6)M(-1); the K(o) of the remaining four-sites was approximately 10(4)M(-1). Thus, the valence of the grouper 16S antibody molecule appears to be eight although the distribution of the high and low K(o) sites is unknown, i.e., are they each on the same or on different molecules? The 16S antibody preparations obtained after more prolonged immunization exhibited increasingly lower K(o) values; the so-called low K(o) sites were no longer detectable. These findings are in contrast to reports of rabbit IgG antibodies showing an increase in K(o) with increased time. The 6.4S antibody preparations obtained from the 1 and 2 month antisera had K(o) values of approximately 10(6)M(-1) and a valence of one. These antibodies would not precipitate with antigen. The 6.4S antibody preparations obtained at later times showed decreasing K(o) values comparable to those of the 16S antibodies from the same bleedings. Studies on the thermodynamic parameters of the hapten-antibody interaction showed the grouper 16 and 6.4S antibodies to be similar to each other. These data also showed that the enthalpy and entropy changes of grouper antibody-hapten reactions resemble those reported for rabbit IgG antibodies to this hapten. It is thus suggested that, although considerable evolution of immunoglobulin classes has occurred between fish and rabbits, the antibody combining site may have remained relatively unchanged during a large part of evolutionary time.

Animals↗
PubMed1969

An evaluation of influenza immunization: influence of route of administration and vaccine strain.

A field study was undertaken in Tampa, Fla., to assess the efficacy of subcutaneous and aerosol methods of administering vaccine, and to compare the protection afforded by bivalent (A2 and B) influenza virus vaccine and by A2/Hong Kong/68 virus vaccine. Further objectives of the study included a comparison of the effectiveness of single-dose and 2-dose immunization. Approximately 2100 volunteers received, in a double-blind manner, both an injection and an aerosol administration on 2 occasions 3 weeks apart. The results showed that aerosol administration gave a lower over-all protection rate, although the booster dose seemed to have a marked effect. The protection afforded by A2/Hong Kong/68 virus vaccine was considerably greater than that afforded by the bivalent vaccine, particularly when administration was subcutaneous. Results are also given on the occurrence of side-effects and on the correlation between cigarette smoking and the occurrence of influenza-like illness.

Aerosols↗
PubMed1967

Colostral immunoglobulin-A: synthesis in vitro of T-chain by rabbit mammary gland.

When minced mammary tissue from lactating rabbits was incubated in vitro with C(14)-labeled lysine and isoleucine, it incorporated radio-activity into colostral immunoglobulin A. The only portion of this colostral molecule with significant labeling was T-chain, with little or no labeling of light or heavy chains. It was thus demonstrated that T-chains are synthesized by mammary gland. Because the remainder of the molecule was derived from unlabeled material, in vivo it was probably derived from serum.

Animals↗
PubMed1967

Phylogeny of immunoglobulin structure and function. I. Immunoglobulins of the lemon shark.

Lemon sharks immunized with bovine serum albumin produced two molecular forms of antibodies detectable by passive hemagglutination of antigen-coated, tanned sheep erythrocytes. Throughout the course of immunization 2-ME-sensitive antibody was associated with a 19S immunoglobulin fraction (4-5 mg/ml serum) while late in the course of immunization antibody was found also associated with a 7S immunoglobulin fraction (7-8 mg/ml serum). No evidence for any anamnestic response was found in these animals. Naturally occurring hemagglutinins for sheep erythrocytes were found to be 2-ME-sensitive and present in the 19S immunoglobulin fraction. These immunoglobulin fractions were readily purified by DEAE-cellulose chromatography and Sephadex G-200 gel filtration. Both immunoglobulin molecules yielded equimolar amounts of H and L polypeptide chains when subjected to extensive reduction and alkylation followed by gel filtration in 5 M guanidine-HCl. Antigenically reactive H and L chains were obtained by partial reduction and alkylation followed by gel filtration in 1 M propionic acid. The 7S and 19S immunoglobulin H chains were indistinguishable by fingerprints of tryptic digests, disc electrophoretic patterns, antigenic properties, and mass (molecular weight approximately 70,000), thus suggesting these two molecules to belong to the same immunoglobulin class. The shark 19S and 7S immunoglobulin L chains were indistinguishable from each other by similar criteria and were different from the H chains. These L chains exhibited the electrophoretic heterogeneity of their mammalian counterparts. The 7S (shark immunoglobulin) molecule was shown to have a molecular weight of approximately 160,000 and to consist of 2H and 2L polypeptide chains (total mass congruent with180,000). The 19S molecule was shown to have a molecular weight of 800,000-900,000; therefore, there were probably five 7S subunits per 19S molecule, comparable to mammalian gammaM. Other reasons for considering the 7S and the 19S lemon shark molecules to belong to a class of immunoglobulins comparable to the gammaM class of mammals are that they both have high carbohydrate contents, and H chains of mass similar to micro chains. The lemon shark serum proteins with electrophoretic mobilities comparable to gamma G of mammals were not related to the immunoglobulins of this species. These proteins had no antibody activity and had no antigenic or chemical similarity to either the H chains, the L chains, or the intact immunoglobulin molecules from the lemon shark.

Animals↗