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Biomedical subjects

J J Marchalonis

Publications and source records attributed to J J Marchalonis.

At least 199 records · Page 11Linked to original sources
PubMed1976

Lymphocyte surface immunoglobulins: detection, characterization, and occurrence in disease of the lymphoid system.

Surface immunoglobulins (Igs) of lymphocytes are of considerable interest because these molecules probably function as receptors for antigen, and knowledge of their molecular properties should provide information on the mechanisms of immune differentiation. The density and types of surface Ig on a cell provide markers useful in indicating the class of a lymphocyte and its stage of maturity. Moreover, knowledge of the specificities of the surface Ig of neoplastic lymphocytes might suggest the nature of agents involved in the generation of the disease. Two broad classes of lymphocytes, bone marrow-derived lymphocytes (B cells) active in antibody secretion, and thymus-derived lymphocytes (T cells) which mediate cellular immune reactions, and their subpopulations must be considered with reference to the nature, origin, and function of their surface immunoglobulin. This article analyzes direct and indirect methods for the demonstration of surface Igs and describes certain physicochemical properties of isolated surface Ig molecules. Roles of these surface molecules in recognition of antigen, initiation of all differentiation, and cooperation among lymphocytes and accessory cells are discussed.

Agammaglobulinemia↗
PubMed1975

Lymphocyte surface immunoglobulins.

Immunoglobulins have been isolated from the surface of B (bone marrow-derived) and T (thymus-derived) lymphocytes. Two types of membrane immunoglobulin occur on B lymphocytes; one type resembles the 200,000-dalton subunit of IgM, the second possesses a heavy chain electrophoretically distinct from mu chain and does not correspond to any of the known classes of mouse immunoglobulins. It might correspond to human sigma chain. T lymphocytes possess only one type of surface immunoglobulin. This molecule has a mass of approximately 200,000 daltons and contains light chains and heavy chains similar to, but not identical to, mu chains. Evidence now exists that surface IgM-like immunoglobulins of B lymphocytes and T lymphocytes activated to certain antigens can bind specifically to antigen. These observations suggest that surface immunoglobulin functions as a receptor for antigen on B cells and at least on some T cells. The mechanisms by which combination of antigen with surface immunoglobulin initiate differentiation remain to be determined.

Animals↗
PubMed1975

Immunoglobulin of T lymphoma cells. Biosynthesis, surface representation, and partial characterization.

Four cloned continuously cultured mouse T lymphoma cell lines, WEHI-22.1, WEHI-7.1, S49.1, and EL-4.1, were examined for immunoglobulin biosynthesis and the presence of immunoglobulin on the cell surface. Incorporation of [-3H]leucine into cellular proteins followed by serological analysis showed that immunoglobulin constituted between 0.1 and 1.1 percent of protein synthesized by the different cell lines during a 6-hr period. Under the same conditions cultured cells of nonlymphoid origin, the mastocytoma P-815 X-2.1, did not synthesize any detectable immunoglobulin. Lactoperoxidase-catalyzed radioiodination was used to label proteins on the surface of viable lymphoma and mastocytoma cells. Although the lymphoma lines lacked immunoglobulin as assessed by fluorescent antibody staining, immunoglobulin was detected in surface proteins of all four lymphoma lines. Estimates of the number of immunoglobulin molecules on the cell surface were 1.1 times 10-4/cell for S49.1 and EL-4.1, 1.7 times 10-4 for WEHI-7.1, and 4.3 times 10-4 for WEHI-22.1. Electrophoretic mobilities in sodium dodecyl sulfate polyacrylamide gel indicated that intact cell surface immunoglobulin was slightly larger than IgG, and on disulfide bond reduction to dissociate into two components, one with the mobility of serum immunoglobulin light chain, the other with a mobility similar to that of mu heavy chain. The heavy chain from the T lymphoma cells possessed an apparent molecular weight of about 65,000 compared with 70,000 for mu chain, although both chains shared antigenic determinants characteristic of mu chains. These findings are interpreted as support for other reports that T lymphocytes carry immunoglobulin on their surface and as direct evidence that thymus-derived lymphoid cells synthesize an immunoglobulin resembling the 7S subunit of IgM.

Animals↗
PubMed1974

Inhibition of a T-cell-dependent immune response in vitro by thymoma cell immunoglobulin.

Concentrated medium obtained from cultures of a continuous thymus-derived mouse lymphoma cell line (WEHI-22.1) was found to inhibit a T-cell-dependent (antidonkey red blood cell), but not a T-cell-independent (anti-DNP) immune response in vitro. Passage of such a concentrate through an anti-mouse Ig immunoadsorbent column removed its inhibitory activity. It is suggested that the tumor cell Ig can compete with specific normal T-cell Ig in its collaborative function in immune responses. A similar mechanism may account for anergy associated with some human lymphoid neoplasms.

Animals↗
PubMed1974

Surface proteins of thymus-derived lymphocytes and bone-marrow-derived lymphocytes. Selective isolation of immunoglobulin and the theta-antigen by non-ionic detergents.

Accessible surface proteins of thymus-derived lymphocytes (T-cells) of normal CBA mice and bone-marrow-derived lymphocytes (B-cells) of congenitally athymic nu/nu mice were analysed. The surfaces of lymphocytes were radioiodinated by using the enzyme lactoperoxidase (EC 1.11.1.7), then solubilized either in acid-urea or in the non-ionic detergent Nonidet P-40. These lysates were then precipitated with antisera specific to either immunoglobulin or the theta-alloantigen in order to assess the presence of these surface markers. Comparable amounts of radioactivity in proteins specifically precipitable as immunoglobulin were obtained from T-lymphocytes and B-lymphocytes when the cells were disrupted by acid-urea. This immunoglobulin had mol. wt. approx. 180000 and was composed of light chains and mu-type heavy chains. When radioiodinated lymphocytes were solubilized with Nonidet P-40, 3-4% of radioiodinated high-molecular-weight protein of B-cells consisted of immunoglobulin, a result similar to that found with acid-urea extraction. However, with the detergent extraction, only 0.1% of T-cell surface protein was precipitable by anti-globulin reagents. The theta-alloantigen was isolated from CBA T-cells both by acid-urea and by detergent lysis. This protein possessed a mobility on polyacrylamide-gel electrophoresis in sodium dodecyl sulphate which was consistent with a mol. wt. of 60000. An identical component was isolated from the theta-positive thymoma WEHI 105. The theta-antigen was not isolated from B-cells by either of the extraction procedures used. These results provide further evidence that the surface membranes of normal T-cells and B-cells differ in physicochemical properties. In particular, various surface components possess differential solubilities in non-ionic or organic solvents. This observation provides an explanation for discrepant results that have appeared in the literature concerning the isolation of immunoglobulin from T-lymphocytes.

Animals↗