Search PubMed⌕ Search

Biomedical subjects

L W Clem

Publications and source records attributed to L W Clem.

At least 127 records · Page 7Linked to original sources
PubMed1971

Production of 19S IgM antibodies with restricted heterogeneity from sharks.

Two of three nurse sharks, Ginglymostoma cirratum, immunized with streptococcal A-variant vaccine, produced over 7 mg/ml serum of 19S IgM antibody to the group-specific carbohydrate. The light chains of this specific antibody from one shark were separated into multiple bands by disc electrophoresis. The light chains from the other antibody-producing animal were much less heterogeneous and gave only one predominant band.

Animals↗
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

Phylogen of immunoglobulin structure and function. 3. Immunoglobulins of the chicken.

Chicken 7.1S immunoglobulin was purified from whole chicken serum by DEAE-cellulose chromatography and Sephadex G-200 gel filtration. The macroglobulin was purified by a combination of salt precipitation and Sephadex G-200 gel filtration. Both immunoglobulin molecules yielded 75% heavy (H) chains and 25% light (L) 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 5 M guanidine-HCl. The 7.1S and 16.7S immunoglobulin H chains were antigenically unrelated to each other, whereas the L chains were antigenically indistinguishable from one another. The 16.7S H chains were found to have a mass of approximately 70,000, and the 7.1S H chains had a mass of 67,500. The mass of the L chains was approximately 22,000. Sedimentation equilibrium studies of the 7.1S immunoglobulin molecule gave a mol wt of approximately 170,000 which is in good agreement with the 179,000 predicted on the basis of 2 H and 2 L polypeptide chains. The 16.7S molecule was shown to have a mol wt of approximately 890,000. A reductive subunit that has a mol wt of approximately 174,000 has been isolated from the 16.7S molecule. These values are consistent with the chicken macroglobulin having five subunits, each of which has 2 H and 2 L chains. The hexose contents of the chicken 7.1S and 16.7S immunoglobulins are 2.2% and 2.6%, respectively. The extinction coefficients of the 7.1S and 16.7S immunoglobulins were 13.18 +/- 0.04 and 12.72 +/- 0.77, respectively, when measured in 0.3 M KCl. Based upon physical-chemical and antigenic characteristics, the 16.7S immunoglobulin most closely resembles IgM of mammals. The 7.1S immunoglobulin definitely belongs to a different class than the 16,7S immunoglobulin, but it does not align itself very well with any of the mammalian immunoglobulins. We propose that this molecule be designated as IgY. Furthermore, this designation would be useful for the immunoglobulins of other species for which there is insufficient correlation with any of the known human immunoglobulins.

Animals↗