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Biomedical subjects

D Pressman

Publications and source records attributed to D Pressman.

At least 91 records · Page 5Linked to original sources
PubMed1975

Electron microscope study on human lymphocyte-sheep erythrocyte rosettes.

Nonimmune rosette formation of human peripheral blood lymphocytes and cultered MOLT 3 and MOLT 4 cells with sheep red blood cells was studied by transmission electron microscopy. At the cell contact area of the rosette, lymphoid and red cell membranes were parallel and 80-100 A apart. The inner leaflet of the lymphoid cell membrane seemed denser, and amorphous substance attached to its cytoplasmic face. The cell contact area was 100-1000 nm wide and frequently on the lymphoiid cell body rather than on microvilli, though some cells extended microvilli near red cells.

Animals↗
PubMed1975

Radioimmunoassay for human T-cell associated antigens on MOLT 4 cultured cells.

We have detected antigens associated with two malignant T-cell lines by use of a sensitive radioimmunoassay. Baboon antisera to a cultured malignant T cell line (MOLT 4F) were prepared and the gammaG-anti-MOLT 4F was enriched by specific adsorption onto, and elution from, MOLT 4F cells followed by repeated absorption with pools of 21 established, long-term cultured B cell lines. Purified 125I-gammaG-anti-MOLT 4F preparation was tested for relative binding to autologous (MOLT 4F) and allogenetic (Sommer-RPMI 8402) T cells as well as B cells, including Sommer B cells (RPMI 8392). The degree of enrichment of antibody to malignant T cell associated antigens, expressed in terms of the ratios of the amount of globulin bound by T cells relative to the amount bound by B cells, were 6.3 and 5.0 for MOLT 4F and Sommer T cells, respectively.

Animals↗
PubMed1975

The expression on mouse lymphoid cells of Th-B, an antigen common to mouse B cells and thymus cells.

A new cell-surface antigen of mouse lymphocytes, which was found earlier on normal and malignant plasma cells and about half the normal thymus cell population, has been shown to be on mature B cells and on the least immunocompetent subpopulation of cells of the thymus. The antigen was first detected by the cytotoxic effect on relevant cells of an in vivo purified rabbit antiserum raised against cells of the mouse IgM-producing plasma cell tumor MOPC-104E. We have now used a cell-transfer method to examine the effect of this antiserum (RantiM104E) on immunocompetent lymphocytes of spleen, including separated splenic B and T cells and thymus and bone marrow cells. We have found the antigen on the immunocompetent B lymphocytes of the spleen, but not on any other of the immunocompetent cells examined. The method involves determining the effect of the antiserum on the development of plaque-forming cells in the spleens of irradiated mice that have received lymphocytes from immune or non-immune donors by treating the lymphocyyes with RantiM104E antiserum before transfer. Plaque-forming cells are suppressed when antiserum-treated spleen cells are transferred to the irradiated mice.This suppression was found to be due to action on only the splenic B cells. The helper activity of splenic T cells was not reduced significantly by antiserum treatment. Neither was the helper activity of thymus cells similarly treated reduced by the antiserum. We found, in fact, that the subpopulation of the thymus cells which is resistant to the antiserum was more immunocompetent than the total thymus cell population. In addition, the hydrocortisone-resistant thymus cells were also found to be resistant to the cytotoxic action of the antiserum. The antiserum had no effect on bone marrow cells in the cell-transfer procedure. The antigen involved, which we are designating "Th-B" appears to be a B cell line marker which appears relatively early during the differentiation of mouse B cells from precursor cells and is lost during maturation of T cells.

Animals↗
PubMed1975

Effect of antimyeloma cell antiserum on immunological enhancement.

Growth of Sarvoma 180 in AKR mice was enhanced by immunization with frozen-thawed homogenates of this tumor. Treatment of host mice with rabbit antimyeloma cell antiserum, either furing immunization or shortly after tumor implantation, resulted in a decreased incidence of tumor rejection or an increased rate of tumor growth. A slow-growing subline from a spontaneous, DBA/2Ha-DD mammary tumor is rejected after initial growth in DBA/2J mice. The incidence of rejection was reduced by treatment with the antiserum studied.

Animals↗
PubMed1975

An experimental model for evaluation of factors in tumor escape from immunological attack.

A model system is presented for studying the factors involved in tumor immunity. The initial observations with this system concern the importance of dose and route of administration of tumor cells on tumor growth. The data show that myeloma tumor cells, when inoculated i.v.in relatively large numbers, are eradicated by the immune response of an allogeneic host; tumor cells administered i.v. in smaller number escape from immune attack even though the host has the potential to mount an immune response. BALB/c mouse myeloma cells (MOPC-21) were transplanted s.c., i.p., or i.v. into H-2-compatible allogeneic DBA/ 2 mice. There was a marked difference in the response of the host to tumor given s.c. or i.p. as compared to tumor given i.v. Thus s.c. or i.p. inoculation resulted in lethal tumor growth when 5 x 10-3 or more tumor cells were given. In contrast, the outcome of i.v. inoculation depended on tumor cell dose. Although small cell doses ( 5x 10-4 down to 10-2) resulted in lethal tumor gosulted in lethal tumor growth with only 10% survival, large cell doses (10-5 to 5 x 10-7) resulted in tumor rejection and 70% survival. DBA/2 mice possess the immunological ability to react agaist the tumor when large doses of tumor cells (10-7) are given i.v. or i.p., since spleen cells obtained from such mice were found to be able to suppress the growth of MOPC-21 when a mixture of spleen cells and tumor cells was inoculated. On the basis of these initial observations, our model appears to relate especially to the idea that, in autochithonous tumor development or in metastasis of tumor, a small number of antigenic tumor cells, perhaps even a single cell, usually grows into a frank tumor in spite of the immunological competence od the host to respond to the tumor cells.

Animals↗
PubMed1975

Papain-solubilized Ag-B antigens. I. Isolated and characterization of two components composing Ag-B antigens.

Ag-B antigen molecules of about 59,000 daltons were partially purified from papain digests of liver cell membranes of Fischer and ACI rats. These preparations were radioiodinated and the labeled Ag-B antigen molecultes were isolated as specific immune complexes with alloantibodies directed to Ag-B1 or Ag-B4. These specifically purified Ag-B antigen molecules were found to give two fragments of 37,000 and 11,000 daltons on sodium sulfate-acrylamide gel electrophoresis. The two fragments (or very similar ones) were isolated from the radioiodinated partially purified Ag-B antigen preparations by acid dissociation and subsequent gel filtration. The 37,000-dalton fragment retained the same Ag-B alloantigenic specificity as the parental 59,000-dalton Ag-B antigen molecules, whereas the 11,000-dalton fragment did not carry any detectable Ag-B alloantigenic activity. In the reaction with rabbit antisera raised against rat cell membranes, each fragment was shown to be antigenically distinctive.

Animals↗
PubMed1975

Papin-solubilized Ag-B antigens. II. Characterization of small sized Ag-B molecules.

Papain solubilization of rat Ag-B histocompatibility antigens produces Ag-B molecules of about 59,000 daltons which have been shown to contain two fragments bound noncovalently: one fragment about 37,000 daltons carrying Ag-B allospecificity, and another about 11,000 daltons, an apparent rat homologue of human beta2-microglobulin. Beside the 59,000-dalton Ag-B molecules, papain digests of liver cell membranes of ACI strain rats were found to contain Ag-B molecules of about 25,000 and 35,000 daltons. These smaller Ag-B molecules carried Ag-B private specificity of the rat strain (i.e., Ag-B4), as did the 59,000-dalton Ag-B molecules, and accounted for 40% of the solubilized Ag-B alloantigenic activity. The smaller Ag-B molecules were tested for the antigenic specificities that are characteristic of each of the two fragments of the 59,000-dalton molecules and detected by rabbit antiserum against rat cell membranes. The 35,000-dalton Ag-B molecules were found to contain the Ag-B 11,000-dalton fragment (i.e., rat beta2-microglobulin homologue) and to differ from the 59,000-dalton Ag-B molecules only in absence of a part of the 37,000-dalton fragment portion. The 25,000-dalton Ag-B molecules did not contain the rat beta2-microglobulin homologue and contained only a single component that is similar to the alloantigenic fragment portion of the 35,000-dalton Ag-B molecules. Similar 25,000-dalton Ag-B molecules (carrying Ag-B1 private specificity) of a single component were found in Fischer rat material. They accounted for 10% of the solubilized Ag-B alloantigenic activity.

Animals↗
PubMed1975

Binding of the azocarcinogen 3'-methyl-p-dimethylaminoazobenzene to cellular components of normal rat liver and azocarcinogen-induced hepatomas.

The location of binding sites for 3'-methyl-p-dimethylaminoazobenzene (3'-Me-DAB) or metabolites on components of rat liver cells and hepatoma cells in tumors induced by this carcinogen was determined at 2 stages during the induction of tumors in rats: (a) in normal liver immediately following the application of a massive dose of the azocarcinogen by intragastric feeding, and (b) in liver and tumor after hepatomas had developed following repeated exposures to the carcinogen by s.c. injections. Bound 3'-Me-DAB or metabolites were detected by the use of rabbit antisera directed against either p-azoazobenzene or p'-azo-p-dimethylaminoazobenzene in an indirect fluorescent antibody technique. Soon after massive intragastric doses of 3'-Me-DAB, the staining observed when the anti-p-azoazobenzene antiserum was used was principally on cytoplasmic components of liver cells with some staining of the intranuclear components. When the second antiserum, anti-p'-azo-p-dimethylaminoazobenzene antiserum, was used, the most intense fluorescent staining was on the nuclear membranes, although there was some cytoplasmic and intranuclear staining as well.

Adenoma, Bile Duct↗
PubMed1975

A surface membrane determinant shared by subpopulations of thymocytes and B lymphocytes.

Utilizing a quantitative fluorescence assay with the fluorescence-activated cell sorter (FACS), we have demonstrated that a rabbit antiserum obtained by immunization with cells of a mouse IgM-producing plasma cell tumor (MOPC104E) is reactive with at least two surface determinants, designated Th-B and ML2, on subpopulations of normal murine lymphocytes. The ML2 determinant is restricted to B lymphocytes. The Th-B determinant is shared by splenic B lymphocytes and a large subpopulation of thymocytes, the latter of which express a 3-fold higher density of Th-B on their surface than do the B lymphocytes. Neither Th-B nor ML2 were found on peripheral T cells or on brain, liver, or kidney cells. The available evidence suggesting that Th-B may be a stem cell determinant that is lost upon maturation is discussed.

Animals↗