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Biomedical subjects

M D Poulik

Publications and source records attributed to M D Poulik.

At least 19 recordsLinked to original sources
PubMed1979

beta 2-Microglobulin: methods and clinical applications.

beta 2-Microglobulin is a low molecular weight protein that is found in most biological fluids. It was originally isolated from urine of cadmium-poisoned patients. Its amino acid sequence was established and shown to be structurally related to immunoglobulin constant domains. With the aid of antibodies specific against beta 2-microglobulin, the protein was detected on the membranes of all nucleated cells, normal and neoplastic. Measuring the quantity of beta 2-microglobulin showed that high levels are present in patients with renal tubular deficiencies and several other pathological conditions including neoplastic diseases. Extremely high levels were detected in seminal fluid and colostrum. Despite the structural relationship to immunoglobulins, no immunological relationship was demonstrated with these proteins using antibodies specific for beta 2-microglobulin. However, such antibodies are cytotoxic to all cells carrying beta 2-microglobulin on their surfaces. The discovery that beta 2-microglobulin is an integral part of the histocompatibility antigens of human and murine origin stimulated further research and interest in this molecule. Several groups of investigators have shown that beta 2-microglobulin is the low molecular weight chain and is noncovalently bound to a high molecular weight chain which carries the histocompatibility antigens. The structure of the histocompatibility antigens of lymphocytes (HLA) was shown by immunochemical as well as biological methods, and it is now well accepted. The antibodies against beta 2-microglobulin are extremely useful in the isolation of the histocompatibility antigens for sequence studies. Furthermore, the antibody to beta 2-microglobulin revealed that other structures may be bound to beta 2-microglobulin such as phytohemoagglutimin (PHA) receptors, mixed lymphocyte culture (MLC) antigens, etc. Murine thymus leukemia (TL) antigen also contains beta 2-microglobulin as an integral part of its structure; other tumor antigens may have a similar structure. Through all these studies, beta 2-microglobulin emerged as the best known membrane protein that can serve as a model for study of the arrangement and the function of the cell membrane.

Amino Acid Sequence↗
PubMed1978

Suppression of lymphocyte proliferation by a nonspecific factor produced by the Burkitt lymphoma-derived lymphoblast cell line.

The DAUDI lymphoblast cell line derived from a patient with Burkitt lymphoma was obtained from two different sources. One of these (DAUDI-I) produced a factor that inhibited lymphocyte proliferation in both human and mouse regardless of the stimulator, i.e. allogeneic lymphocytes or mitogens. Glutaraldehyde treatment eliminated production of the factor and demonstrated that DAUDI-I was capable of stimulating normal lymphocytes in MLR. A second DAUDI cell line (DAUDI-S) did not produce the inhibitory factor and was capable of MLR stimulation.

Animals↗
PubMed1976

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.

Animals↗
PubMed1976

beta 2-microglogulin levels in cancerous and other disease states.

Serum beta2-microglobulin levels were measured, by radioimmunoassay, in patients suffering from a variety of benign and malignant clinical disorders. Elevated beta 2-microglobulin values were found in neoplastic and non-neoplastic disorders affecting a variety of organs. The most striking increases in beta 2-microglobulin are found in the plasma cell dyscrazias and several solid tumors, particularly those affecting the lung. Lymphoid neoplasms demonstrate a spectrum of changes of serum beta 2-microglobulin. At the one end of this spectrum were the plasma cell tumors, which show a high incidence of raised beta 2-microglobulin levels, while patients with Hodgkin's disease rarely show such increases in circulating beta 2-microglobulin.

Beta-Globulins↗
PubMed1976

beta2-microglobulin locus on human chromosome 15.

We have developed an autoradiographic/electrophoretic assay capable of distinguishing mouse and human beta2-microglobulin (beta2m) in spent culture media. The method is applicable to mouse and human lines and to hybrid cell lines made from them. With this technique, mouse/human hybrid cell lines were tested for the presence of human beta2m. Isozyme and karyotype analyses were also carried out with the hybrids. The combined results of these studies show that the structural gene for human beta2m is on the long arm of chromosome 15.

Beta-Globulins↗
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↗
PubMed1976

beta2-Microglobulin: a reevaluation.

Rabbit antiserum to human beta2-microglobulin was used to inhibit the proliferative response of lymphocytes in a variety of in vitro assays and to block the effector phase of the cell mediated lympholysis reaction. The antiserum was able to inhibit both of these reactions; it is not clear whether the cytotoxic reaction that we are studying in a xenogeneic human-rabbit system is based on phytohemagglutinin dependent cytotoxicity or on specific recognition of target cells by receptors on the effector cells, or most likely on a combination of both cytotoxic mechanisms. Whereas the possibility that beta2-microglobulin may be associated with receptors on the thymus-derived lymphocyte surface is considered, it is also pointed out that the effect of the antiserum may be based on other mechanisms of perturbing the membrane so as to inhibit these responses.

Antigen-Antibody Reactions↗