Gary N. Trump

Muscle palmitate uptake and binding are saturable and inhibited by antibodies to FABP(PM).

Studies show that uptake of long-chain fatty acids (LCFA) across the plasma membranes (PM) may occur partly via a carrier-mediated process and that the plasma membrane fatty acid-binding protein (FABPPM) may be a component of this system. To test the hypothesis that FABPPM is involved in transsarcolemmal transport of LCFA in muscle, we measured palmitate uptake in giant sarcolemmal vesicles and palmitate binding to PM proteins in rat muscles, (1) in the presence of increasing amounts of unbound palmitate and (2) in the absence or presence of antibody to FABPPM. Both palmitate uptake and binding were found to be saturable functions of the unbound palmitate concentration with calculated Vmax values of 10.5 ± 1.2 pmol/mg protein/15 sec and 45.6 ± 2.9 nmol/mg protein/15 min and Km values of 12.8 ± 3.8 and 18.4 ± 1.8 nmol/L, respectively. The Vmax values for both palmitate uptake and binding were significantly decreased by 75-79% in the presence of a polyclonal antibody to the rat hepatic FABPPM. Antibody inhibition was found to be dose-dependent and specific to LCFA. Glucose uptake was not affected by the presence of the antibody to FABPPM. Palmitate uptake and binding were also inhibited in the presence of trypsin and phloretin. These results support the hypothesis that transsarcolemmal LCFA transport occurs in part by a carrier-mediated process and that FABPPM is a component of this process in muscle.

Immunogenicity of Two Naturally Occurring Solid-Phase Enamel Proteins

Summary An antiserum to native, solid-phase, insoluble enamel proteins from New Zealand white rabbits was raised in the same strain of animal. The ability of the antiserum to bind enamel proteins was demonstrated by fluorescence and radioimmu-noelectrophoretic techniques. The data were interpreted to suggestthat enamel proteins are sequestered from immune surveillance during early development, resulting in subsequently induced autoantibody production. This research was supported by Grants DE-00095, DE-02848, and DE-03513 from the National Institutes of Health, and by a grant from the California Dental Association.

Isolation of Wilm's tumor antigens by chelation

A procedure for ethylenediaminetetraacetate extraction of minced Wilms tumor was assessed as a method for isolating Wilms tumor antigens. An antigen was detected by immunodiffusion using an adsorbed antiserum to this extract. This antigen was also found in ethylenediaminetetraacetate extracts of in vitro cultures of nephroblastoma cells.

Pulpal studies. I. Passage of 3H-tetracycline into circulatory system through rat molar pulps

Abstract Rats were used to study the fate of a radioactive antibiotic placed on injured pulpal tissue. Radioactivity found in the general circulation within 10 minutes after application was shown to be due to protein-bound, native, tritiated antibiotic.

Immune function in congenital osteopetrosis: defective lymphocyte function in microphthalmic mice.

Osteopetrosis is a prominent feature of a congenital mutation described in microphthalmic mice and is thought to be due to defective osteoclast function which causes a generalized lack of bone resorption. Reversal of defective bone resorption in osteopetrotic mutants has been achieved by hematopoietic cell transplantations; and conversely, defective bone resorption has been transferred to normals by hematopoietic cells from osteopetrotic littermates. This suggested that osteopetrotic mutants might also demonstrate defective immune functions which could in turn be related to the lack of normal bone resorption. To that end, aspects of in vitro lymphocyte function in microphthalmic mice were compared to those of their phenotypically normal littermates. There was a significant diminution in the proliferative response of splenocytes to mitogens in microphthalmic mice. Microphthalmic splenocytes also were less responsive in an in vitro assay which measured the capacity to form antibody forming cells.

Preparation of two solid phase immunogens.

Abstract Dinitrophenyl (DNP) conjugates of Bio-Gel and dinitrophenyl-ornithine conjugates of Bio-Gel and Sepharose were prepared. Their efficacy as immunogens was assessed. It was found that the dinitrophenyl-ornithine gels ellicited generation of large numbers of splenic anti-DNP plaque-forming cells. DNP-Bio-Gel was not immunogenic.

Preparation of mouse type I and type II insulins for immunologic studies

Mouse pancreata contain comparatively meager amounts of two insulin species, types I and II. When these insulins are to be prepared for immunogenetic studies, it is desirable to obtain equivalent amounts of both in concentrations suitable for immunization. Standard methods, based on isolating single species, favor recovery of one type. Moreover, published methods for separation of type I from type II produce very dilute insulin solutions. Methods are suggested here to overcome these disadvantages.

Immunogen structure and cell selection. II. Preparation of a minimal solid-phase immunogen for use in minicultures☆

Abstract A solid-phase haptenic immunogen has been prepared which is of extremely simple structure. This immunogen, DNP-PAB, is prepared through the reaction of the hydrazide derivative of polyacrylamide beads with dinitrobenzenesulphonic acid. A new method is presented for quantifying the number of haptenic groups. DNP-PAB is very immunogenic for dissociated mouse spleen cells in culture, and the anti-hapten response is highly specific.