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R A Reisfeld

Publications and source records attributed to R A Reisfeld.

At least 199 records · Page 11Linked to original sources
PubMed1978

Serologic and immunochemical characterization of HLA-A9 xenoantisera.

The specificity of A9 antiserum produced in rabbits immunized with high density lipoprotein-associated HLA-A9 from serum was investigated by using serologic and immunochemical approaches. After suitable absorption, the xenoantiserum No. 2958 is monospecific for A9 antigens in direct cytotoxic test. Data from lysostrip experiments and from blocking of cytotoxicity with Fab2 fragments indicate that the A9 xenoantiserum No. 2958 react with the same or closely associated antigenic structures recognized by A9 alloantisera. Immunoprecipitates obtained with the specific xenoantiserum No. 2958 and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis contained only proteins of the size of detergent-solubilized HLA and beta2-microglobulin (45,000 and 12,000 m.w.). Immunodepletion experiments indicated that the precipitation was mediated by antibodies directed to the heavy chain, and not the light chain of the complex. These results indicate that monospecific HLA-A9 xenoantisera have the same discriminatory capacity of alloantisera and can be useful for the serologic and immunochemical characterization of HLA antigens.

Absorption↗
PubMed1977

Expression of histocompatibility (HLA) antigens on tumor cells and normal cells from patients with melanoma.

The expression of HLA antigens and beta2-microglobulin (beta2-mu) on cultured melanoma cells originated from 11 patients has been quantitated and compared with that on fibroblasts and cultured human lymphoid cells originated from the same patients. No qualitative or quantitative difference was detected with the exception of one melanoma line. HLA antigens were also quantitated in sera from melanoma patients: two sera reacted with anti-HLA-B7 antibodies although this specificity was not expressed on lymphocytes from whom the sera were obtained. A technique to quantitate HLA antigens on cells developed in the course of this study is described.

Cell Membrane↗
PubMed1977

Semi-automatic solid-phase radioimmunoassay for carcinoembryonic antigen.

A solid phase, double antibody radioimmunoassay has been semi-automated for the quantitation of carcinoembryonic antigens. Sepharose-bound rabbit anti-goat IgG immunoglobulin was used as the second antibody, reactions were carried out in 96-well microtiter plates, and samples processing (filtration and washing) was accomplished with the aid of a 24-sample harvester.

Carcinoembryonic Antigen↗
PubMed1977

Immunogenicity of HLA antigens purified from serum.

The immunogenic properties of HLA-A9 antigens isolated from serum have been evaluated. A9 antigens at various stages of purification can elicit the formation of cytotoxic antibodies which become operationally specific to A9 either after absorption of the xenoantisera with cultured human lymphoid cells or human red blood cells, or after dilution of xenoantisera with human serum. A9 xenoantisera do no affect mixed lymphocyte reactions between allogeneic lymphocytes carrying A9, suggesting that coating of antigens of the A locus does not impair the functional activity of lymphocytes in the mixed lymphocyte reaction.

Animals↗
PubMed1977

Immunogenicity of human B cell antigens solubilized from cultured human lymphoid cells.

Antigens solubilized from culured human lymphoid cells WI-L2 and RPMI 1788 were partially purified by ultracentrifugation on a KBr gradient. These antigens injected into rabbits produced xenoantibodies which after absorption with melanoma cells became specific to B cell antigens. Three such xenoantisera were submitted to the Second Histocompatibility Workshop of the Americas and reacted much like alloantisera to B cell antigens against a large panel of B peripheral lymphocytes and cells from patients with chronic lymphocytic leukemia. Xenoantisera to B cell antigens inhibited the mixed lymphocyte reaction, but did not affect the mitogenic activity of phytohemagglutinin or the functional properties of C3 receptors, monkey red blood cell receptors, or T cell receptors.

Antibodies↗
PubMed1977

Biologic and chemical characterization of HLA antigens in human serum.

HLA antigens of both the A and B loci were shown to be associated with the high density lipoprotein fraction of serum prepared by ultracentrifugal flotation. HLA-A9 antigens were purified 100-fold with essentially complete recovery by a simple procedure of high density lipoprotein preparation involving precipitation with polyanions and ultracentrifugal flotation. The purified lipid-associated antigen was immunogenic since it elicited the formation of cytotoxic xenoantibodies in rabbits. Serum HLA-A9 antigens were found by immunoprecipitation and gel electrophoresis to consist of a 45,000 m.w. heavy chain associated with beta2-microglobulin. The size of the HLA-lipid complex (less than 190,000 m.w.) and of the HLA-deoxycholate complex (less than 102,000 m.w.) suggests that HLA antigens are shed into plasma as a complex of a single HLA molecule and a single beta2-microglobulin chain, associated with boundary lipid.

Antibodies↗
PubMed1977

Approaches for the isolation of biologically functional tumor-associated antigens.

Melanoma-associated antigens were isolated from human melanoma cells in long-term tissue culture and from the spent culture fluid of these cells propagated in chemically defined, serum-free media. The 3 M KCl extracts from such cells and their concentrated spent culture media elicited specific delayed cutaneous hypersensitivity reactions in patients with malignant melanoma but not in patients with other neoplasms. HLA antigens present in these extracts could be specifically removed by ultracentrifugation in KBr at a density of 1.23 g/ml. Purification of melanoma-associated antigens was achieved by this step, followed by ion-exchange chromatography and preparative isoelectric focusing on Pevikon C870. Another approach is described for the isolation of carcionembryonic antigens from metastatic lesions with an approximately 70% yield utilizing the least denaturing procedures, which avoid lyophilization and involve essentially 0.9% NaCl solution extraction, specific adsorption, elution from concanavalin A Sepharose, and subsequent gel-exclusion chromatography on Ultrogel AcA 22. For effective isolation of carcinoembryonic antigens freely shed from cultured cells derived from a primary colon tumor, a system was devised based on the use of Amicon hollow fiber culture units, in which cultured tumor cells were introduced in the extracapiliary spaces of such a unit. The extracapillary fluid, containing carcinoembryonic antigens but no fetal calf serum components, is removed and further purified by affinity chromatography.

Animals↗
PubMed1977

The immunologic and molecular profiles of HLA antigens isolated from urine.

Human urine was shown to be a good source for the isolation of immunologically functional HLA-A9 antigens. The use of complex solubilization procedures can be avoided since the antigens are present in soluble form and are not complexes with membrane fragements. Purification in excess of 400-fold could be achieved by the application of cellulose ion exchange chromatography, isoelectric focusing, and acrylamide gel electrophoresis. The purified HLA-A9 antigen is composed of a glycoprotein of m.w. 38,000 and beta2-microglobulin, a peptide of m.w. 12,000. HLA-A9 antigens isolated from urine proved to be immunologically functional since they not only reacted specifically with anti-HLA-A9 alloantibody but also elicited anti-HLA-A9 xenoantibodies. These antibodies when covalently attached to Sepharose 4B specifically bound HLA-A9 antigens isolated from both serum and urine.

Arginine↗
PubMed1976

Isolation of a soluble tumor-associated antigen from human melanoma.

Human melanoma-associated antigen was solubilized from fresh surgical specimens by 3 M KC1 extraction. The antigenicity of this extract was demonstrated by delayed cutaneous hypersensitivity responses and inhibition of complement fixation. Twenty-one of 33 melanoma patients had delayed cutaneous hypersensitivity responses to melanoma antigen, while only four of 28 reacted to autologous muscle. Although KC1 extracts did not fix complement directly, they reacted with antibody, thus inhibiting complement fixation by the autologous melanoma antigen extracted from tissue culture supernatants. The soluble antigenic moiety was then purified by fractionation on a G-150 Sephedex column and polyacrylamide gels, and the antigenic activity was monitored by delayed cutaneous hypersensitivity responses in melanoma patients. A 20-fold purification was achieved. Solubilization of tumor antigens with 3 M KC1 provides tumor-associated antigen of high activity which is amenable to further biochemical purification.

Antigens, Neoplasm↗
PubMed1976

Humoral sensitization in parous women: cytotoxic antibodies to non HL-A antigens.

From sera of parous women, we selected 100 samples that lacked cytotoxic antibodies to human peripheral lymphocytes from at least 80 unrelated persons. These sera were then reacted with a panel of 17 cultured human lymphoid cells in the complement-dependent cytotoxic test. Forty-six sera contained cytotoxic antibodies apparently directed to an antigenic system distinct from HL-A antigens, and other known cell surface markers. Rabbit serum was the most efficient source of complement with these cytotoxic antibodies which did not appear to be directed to tumor associated antigens: in fact, no lysis of melanoma cells or leukemic cells could be detected. Ten specificities could be identified which were represented on the cultured human lymphoid cells in various combinations. It is suggested that antigens detected by this approach may be similar to the Ia antigens of the mouse.

Antibody Formation↗
PubMed1976

Inhibition of T-lymphocyte rosetting by HL-A alloantisera and complement.

The relationship between HL-A antigens and rosetting of sheep red blood cells (SRBC) with peripheral human lymphocytes has been investigated by incubating them with HL-A antibodies. Although sensitizing the lymphocytes with HL-A alloantisera had no effect on their ability to form rosettes with SRBC, further sensitization with C6 deficient rabbit serum as a source of early complement components inhibited the formation of rosettes with SRBC. The involvement of HL-A alloantibodies in the inhibition of rosette formation was shown first by correlating the HL-A phenotype of the lymphocytes and the HL-A specificity of the alloantisera and, second, by specifically absorbing the HL-A alloantibodies from the alloantisera. Complement was needed to inhibit rosette formation since this effect was lost when rabbit serum was treated to inactivate complement. The participation of complement's classical pathway in rosette inhibition was shown by chelating the Ca2+ ions by EGTA treatment of the C6 deficient rabbit serum. Perhaps, binding of HL-A antibodies and early complement components to the lymphocyte surface disturbs the distribution of the receptors or affects the charge of the cell membrane, thus inhibiting the rosette formation with SRBC.

Antigen-Antibody Reactions↗
PubMed1976

Characterization of Ia antigens in mouse serum.

Sera obtained from normal B10.BR mice were shown to inhibit selectively a specific anti-Ia alloantiserum. Partial purification of the Ia antigenic activity was accomplished by isolation of the high density lipoproteins from these sera by fractional precipitation with sodium phosphotungstate and MgCL2. Both H-2.23 and Iak antigens present in this high density lipoprotein fraction were completely adsorbed by rabbit anit-rat beta2-microglobulin immunoadsorbents, whereas specific anti-H-2.23 immunoadsorbents removed only the H-2 activity. These data deomnstrate that Ia antigens, like H-2 antigens in the sera of B10.BR mice are associated with high density lipoproteins and further suggest that both H-2 and Ia antigens are associated with a beta2-microglobulin-like molecule.

Animals↗