Beta 2-microglobulin is selectively associated with H-2 and TL alloantigens on murine lymphoid cells.

We have used a rabbit antiserum prepared against purified rat beta2-microglobulin to immunoprecipitate molecules from lysates of radioiodinated murine thymocytes and splenocytes. All the molecules that are reactive with this serum have subunits of 44,000 and 12,000 and can be identified as H-2 and TL antigens. Thus, the anti-beta2mu serum can deplete lysates of the majority of the TL and H-2 atigens which can be subsequently recognized by alloantisera. If TL and H-2 are precipitated from the lysates before the addition of anti-beta2mu, no beta2mu-reactive molecules remain. Our results indicate that Ia antigens cannot be depleted from the lysates with anti-beta2mu. The studies also suggest that TL and H-2 heavy chains can exist as both monomers and dimers. These observations are discussed with regard to previous studies concerning the native structure of H-2 and TL antigens.

Association of the H-Y male antigen with beta2-microglobulin on human lymphoid and differentiated mouse teratocarcinoma cell lines.

The expression of the H-Y antigen has been tested on several human lymphoid lines and mouse teratocarcinoma cell lines during differentiation. The human male lymphoid cell line Raji is a very useful target for studies of the H-Y antigen by lymphocytotoxicity test with rat anti-H-Y sera. With a few exceptions, all cells carrying the Y chromosome were H-Y positive. One of the exceptions is the human Daudi cell line which, besides lacking H-Y antigen, also lacks beta2-microglobulin. We have studied a possible association between the H-Y antigen, beta2-microglobulin, and HLA antigen with redistribution experiments. The results strongly suggest that H-Y antigen is not associated with HLA antigens but with beta2-microglobulin.

Lack of association of serologically detectable human melanoma-associated antigens with beta 2 microglobulin: serologic and immunochemical evidence.

Serologic and immunochemical assays showed that human melanoma-associated antigens (MAA) identified with operationally specific xenoantisera were neither spatially nor structurally associated with beta 2-microglobulin (beta 2-mu), the light chain of the HLA-A,B antigen molecular complex; i.e., cultured melanoma cells coated with a specific anti-beta 2-mu xenoantiserum maintained their reactivity with anti-MAA xenoantisera. Furthermore, soluble MAA were not bound by a beta 2-mu immunoadsorbent. Finally, MAA were shed into the culture medium of melanoma cells and then were immunoprecipitated with specific anti-MAA xenoantisera, analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, they appeared as two distinct structures with molecular weights of 240,000 and 94,000 but comprised no structure with the characteristic 12,000 molecular weight of beta 2-mu. Conversely immunoprecipitates obtained by the reaction of spent culture medium of [3H]valine-labeled melanoma cells with anti-beta 2-mu xenoantiserum had the 12,000-molecular-weight component but no structures with the molecular weights established for MAA. Thus the data refute the contention that serologically detectable MAA have a molecular structure similar to that of HLA antigens.

Association of melanoma tumor antigen activity with beta2-microglobulin.

The majority of melanoma tumor antigen activity present in melanoma extracts derived from fresh tumor tissue binds to a Sepharose-anti-beta2-microglobulin adsorbent. Removal of HLA antigens from the extracts of melanoma tissue by using a KBr flotation technique did not reduce either the tumor antigen activity of the extracts or the binding of melanoma tumor antigen (MTA) activity to the Sepharose-anti-beta2-microglobulin adsorbent. The complete blocking of MTA activity by pretreating the anti-beta2-microglobulin adsorbent with beta2-microglobulin and the lack of detectable MTA binding to a Sepharose anti-normal human serum adsorbent demonstrated the specificity of the binding of MTA to the anti-beta2-microglobulin adsorbent.

Human platelet basic protein. Its relation to low affinity platelet factor 4 and beta-thromboglobulin.

Human beta-thromboglobulin, low affinity platelet factor 4 and platelet basic protein have been purified to homogeneity from the material released by thrombin-stimulated platelets. Purification steps included isoelectric focusing and heparin-agarose chromatography. Antibodies against each of these proteins have been raised in rabbits. Antigenic identity of the proteins has been demonstrated in radioimmunoassay using 125I-labelled platelet basic protein or 125I-labelled low affinity platelet factor 4 and a variety of antibodies. The molecular weight of platelet basic protein estimated by gel filtration in 6 M guanidine hydrochloride using Sepharose 6B corresponded to approx. 10 000 daltons, slightly higher than that of beta-thromboglobulin (8851 daltons) and low affinity platelet factor 4 (9278 daltons). These findings raise the possibility that the formation of low affinity platelet factor 4 beta-thromboglobulin may be a consequence of the action of proteolytic enzymes on platelet basic protein.

Membrane expression and synthesis of p23,30 (HLA-DR antigen) by human peripheral blood monocytes.

The synthesis and expression of protein complexes of 23,000 and 30,00 dalton (p23,30) HLA-DR antigen, and of 44,000 and 12,000 dalton (p44,12) HLA-A,B antigen and beta 2-microglobulin was demonstrated on human peripheral blood monocytes and in cultures of purified, adherent monocytes. In indirect immunofluorescence assays, a gradation in the intensity of staining with rabbit anti-p23,30 serum was present but clearly p23,30-negative, actively phagocytic monocytes were not found. In contrast the fluorescence intensity of staining with a serum to p44,12 (HLA-A,B antigens and beta 2-microglobulin) was constant on all macrophages. Macrophage HLA-DR antigen was shown in SDS gels of immunoprecipitates of 35S-methionine-labeled, detergent-solubilized membrane proteins to be composed of 29,000 and 34,000 dalton, noncovalently linked chains, which form was indistinguishable from that of B lymphoblastoid cell line HLA-DR antigens. The rate of synthesis of HLA-DR antigen was about 17% of that of synthesis of HLA-A,B antigens in adherent macrophage populations. The variable expression of p23,30 on peripheral blood monocytes was consistent with the view of the existence of subsets of such monocyte populations. These findings were compared to studies by others of the variable expression of Ia antigens on human, murine and guinea pig monocytes populations.

Absence of a serologically detectable association of murine beta2-microglobulin with the embryonic F9 antigen.

The association of murine beta2-microglobulin to the early embryonic F9 antigen has been investigated by indirect immunofluorescence and by radioimmunoassay. Although some cell lines carry both types of molecules, the beta2-microglobulin was not found expressed on primitive teratocarcinoma cells, where F9 antigen was primarily detected. It is concluded that the low m.w. (12,000 daltons) subunit that was reported to be associated to the F9 antigen is not the adult beta2-microglobulin.

Autoantibodies specific to beta-2-microglobulin inhibit the Fc receptor-dependent phagocytosis of human monocytes.

Effect of anti-beta2-microglobulin (beta2m) antibodies was investigated on the in vitro Fc and C3 receptor dependent phagocytic capacity of human peripheral monocytes. Both rabbit and human anti-beta2m antibodies inhibit the Fc receptor-mediated phagocytosis. Anti-beta2m antibodies do not influence the spontaneous or C3b receptor-mediated ingestion. The inhibitory activity by human autoantibodies but not by rabbit anti-human beta2m antibodies was diminished when incubation was performed at 37 degrees C instead of 20 degrees C.

Antigen-specific non-immunoglobulin "antibody'-like molecules in rhesus monkey serum.

The presence (in sera of rhesus monkeys) of four antigen-specific molecules with different electrophoretic mobilities apart from conventional immunoglobulins has been recognized. Rhesus monkeys have been primed with rabbit erythrocytes (RRBC) and the antigen-specific molecules in the serum have been fished out by absorption onto RRBC. Antisera have been raised in rabbits against such molecules and analysed by immunoelectrophoresis. The antigen-binding property of the four molecules, which do not resemble conventional immunoglobulins has been confirmed by enzyme immunoelectrophoresis. The possibility of these molecules being products of T lymphocytes in the light of observations reported in recent years is discussed.

Interference of beta 2-microglobulin specific autoantibodies with EA-binding of human peripheral lymphocytes; inhibition of B-cell and enhancement of T-lymphocyte Fc-receptors.

The effect of anti-beta 2 m-specific autoantibodies was investigated on the FcRs of human PBMCs. Anti-beta 2 m autoantibodies inhibited the FcRs of the lymphocyte subpopulation detectable by rosetting with EA(hu). On the contrary, when EA(ox) indicator system was used, in the majority of the cases an enhancement of EA rosette formation was detected. Using separated lymphocyte subpopulations we found that the binding of anti-beta 2 m autoantibodies increased the number of FcR+ non-B-cells and inhibited that of B-lymphocytes.

A precipitin for human serum proteins as released under stress by a marine invertebrate, the marsh snail, Littorina irrorata.

A substance released into the environment by stressed marsh snails, Littorina irrorata, precipitates with the beta globulin and albumin fractions of human serum proteins. Other diverse invertebrate species may produce a similar substance. Invertebrate precipitins have not been widely reported, and none like the one described. Some physicochemical and adaptive characteristics of the snail precipitin are presented. This precipitin can be produced in large quantities and has potential application as a diagnostic reagent.

Changes in the expression of HLA and beta 2-microglobulin by cultured lymphoid cells.

Changes in the expression of HLA and beta 2-microglobulin (beta 2-m) antigens by cultured human lymphoid cell lines were investigated. HLA expression was assayed by indirect trace binding radioimmunoassay (RIA) with monoclonal antibodies and by determining sensitivity to complement-dependent lysis by alloantisera. Lymphoid cells in culture were found to undergo changes in the expression of HLA and beta 2-m antigens characterized by decreased membrane expression of these antigens at high cell densities or after a prolonged period of cultivation. The decreased expression of HLA and beta 2-m antigens apparently is due neither to a masking phenomenon nor to a lack of nutrients or an accumulation of metabolites in the culture media but is perhaps mediated by a cell-to-cell contact mechanism. Human interferon was found to enhance the expression of HLA and beta 2-m, apparently overriding the effects on major histocompatibility complex (MHC) expression induced by cell density.

Associated peptides isolated from human seminal fluid containing beta 2-microglobulin determinants.

Proteins in human semen that react with a monoclonal mouse antibody to human beta 2-microglobulin (h beta 2M) have been isolated using immunoaffinity chromatography. As well as material of the same size as h beta 2M, a peptide of approximately 18000 kdaltons was isolated. It is suggested that this substance either contains h beta 2-M sequences itself or, as is more likely, is non-covalently associated with an h beta 2M-like peptide chain.

Expression of beta 2-microglobulin on preimplantation pig embryos.

The expression of beta-2 microglobulin (beta 2m), a protein associated with the histocompatibility antigens of the pig complex (SLA), was studied in preimplantation embryos between the segmentation stage and the beginning of elongation (day 12). The antigen was visualized at the ultrastructural level by immunocytochemical techniques using peroxidase or colloidal gold particles as labels. beta 2m expression appeared to parallel trophoblast differentiation. No positive reaction was obtained before the early blastocyst stage. From this stage on, labelling was observed on the apical surface of the trophectoderm cells.

Isolation and amino terminal sequence of beta-trace, a novel protein from human cerebrospinal fluid.

beta-Trace, a 23.5 kDa glycoprotein of unknown biological functions, is present in all body fluids tested. It is found in higher concentration in human seminal fluid and cerebrospinal fluid (CSF) than in serum. A one-step procedure for the isolation of beta-trace from pooled CSF is described, by affinity chromatography using a specific antibody made against beta-trace. Amino terminal sequence analysis yields the sequence A P E A Q V S V Q P N F Q Q D K F L G with no homology to known proteins, indicating that beta-trace is a novel CSF protein.

Rheumatoid factors bind beta 2 microglobulin. Detection of beta 2 microglobulin-complexes in rheumatoid arthritis.

beta 2 Microglobulin binding rheumatoid factors and occurrence of complexed form of beta 2 microglobulin were found in rheumatoid arthritis (RA) by radioimmunological methods. 1. As related to the appropriate values of control sera and osteoarthritic synovial fluids, one of the six sera and five of the six synovial fluids of RA patients exhibited increased binding activity for 125I-beta 2 microglobulin, 2. Rheumatoid factors (RF) purified by means of immunoadsorbent bound beta 2 microglobulin; 3. Both 19S and 7S components of sera, synovial fluids and purified RF samples had beta 2 microglobulin binding activity, which was inhibited by an excess of unlabeled beta 2 microglobulin; 4. Complexed (3% PEG 6000 insoluble) beta 2 microglobulin was found in three of fourteen sera and in twelve of fourteen synovial fluids of RA patients. Level of complexed beta 2 microglobulin was independent of its total concentration in the original samples; 5. In the fraction of synovial fluids enriched immune complex the amount of beta 2 microglobulin was in positive correlation with quantity of RF. Presumable immunological and pathological significance of "anti-beta 2 microglobulin"-like cross-reactive RF antibodies is discussed.

Beta-2 microglobulin--an immunogenetic marker of inflammatory and malignant origin.

Major contributions have been made in the last few years to the knowledge of the structure, fate and cellular origin of beta-2 microglobulin (B2M); but the question of its function still remains unclear. The concept of B2M being simply a marker of renal physiology seems less satisfactory when reference is made to its relationship to the immunogenetic system. Although assay of B2M cannot be considered as a specific diagnostic tool, it still may be regarded as a useful parameter in monitoring inflammatory, malignant, and auto-immune disease activity.

beta 2-Microglobulin and transplantation antigens.

The complete amino acid sequence of papain-solubilized HLA A, B and C antigens representing the cell surface-expressed portion of the transplantation antigens has been elucidated. The HLA antigen heavy chains seem to be composed of three domains, one of which binds beta 2-microglobulin. The HLA antigen heavy chain domain closest to the membrane displays striking amino acid homology with immunoglobulin light and heavy chains and with beta 2-microglobulin. The other two domains, which show no statistically significant homology with immunoglobulins, are related to each other. This suggest that the HLA antigen heavy chains have arisen by a series of gene duplication events.

[In vitro study of the sensitizing activity of an antirabies immunoglobulin and its fractions]. / Izuchenie in vitro sensibiliziruiushchei aktivnosti antirabicheskogo immunoglobulina i ego fraktsii.

The dynamics of the blood in guinea pigs sensitized with heterogenous antirabic immunoglobulin was studied. The damage of neutrophils in the blood was found to be an index which allowed to detect changed sensitivity to heterogenous protein already at an early period (on day 6) after immunization, whereas the indirect mast cell degranulation test detected it only at a later period (on day 21). The above methods revealed that beta 1 and beta 2 globulin fractions possessed high sensitizing activity.

[Physicochemical characteristics of a specific beta 1-globulin in the blood serum of pregnant women]. / Fiziko-khimicheskaia kharakteristika spetsificheskogo beta 1-globulina syvorotki krovi beremennykh zhenshchin.

Some physico-chemical properties of beta1-globulin (BGG) (the protein specific for pregnancy) were estimated. BGG was shown to be glycoprotein, possessing the antigenic individuality. The heterogeneity of the protein studied was observed in salt fractionation, polyacrylamide gel electrophoresis, ion exchange chromatography and isoelectrofocusing; this demonstrates the existence of various BGG fractions.