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T Diamantstein

Publications and source records attributed to T Diamantstein.

At least 145 records · Page 8Linked to original sources
PubMed1987

Evaluation of antigen presentation by a murine Ia+ T-cell clone, BK-BI-2.6.C6.

The capacity of cloned murine Ia-positive BK-BI-2.6.C6 T cells to present protein antigens to antigen-reactive long-term cultured T-cell lines was investigated. Antigen recognition by T-line cells on presenting BK-BI-2.6.C6 T-accessory cells resulted in efficient production of lymphokines. While antigen-dependent T cells with transient interleukin-2 receptor (IL-2R) expression were not induced to proliferate, T cells with constitutive IL-2R expression proliferated in response to the secreted IL-2. Although antigen presentation by BK-BI-2.6.C6 T cells resulted in a slight induction of IL-2R expression on responding T cells, as measured by flow cytometry, this augmentation was much smaller than that induced by antigen-presenting spleen cells. Thus the inability of antigen-presenting T-accessory cells to stimulate proliferation of responding T cells with transient IL-2R expression appears to reflect a lack of signal(s) necessary for the induction of IL-2R up to a level critical for initiation of cell division. This test system represents an ideal model to investigate the nature of signals required, in addition to triggering of the T-cell antigen receptor, for the induction of IL-2R.

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PubMed1986

Construction of rat-mouse T cell hybridomas that express regulatable rat interleukin 2 receptor.

Spleen cells obtained from Lewis rats were cultured with 4 micrograms/ml Con A for 96 hr, and activated cells were fused with BW5147 mouse T lymphoma cells. Seven clones obtained by fusion expressed rat IL 2R. The expression of rat IL 2R on those hybrid cells could be up-regulated by IL 2 itself, ATL-derived factor, and TPA and CA++ ionophore. Those IL 2R could be down-regulated by murine MoAb ART-18 that detects rat IL 2R. All hybrid clones produced IL 2 constitutively. IL 2 produced by hybrid cells bound to its receptor and promoted the proliferation of hybrid cells in some clones. Incubation of cells with exogenous IL 2 resulted in the proliferation of hybrid cells, whereas the proliferation of some clones was inhibited by exogenous IL 2, indicating that IL 2 had bifunctional properties on cell growth. Rat IL 2R from 6H2-F9 hybrid cells was studied by both one- and two-dimensional SDS-PAGE with ART-18. The IL 2R derived from 6H2-F9 cells had 72,000 to 77,000 and 40,000 to 48,000 m.w. major components under nonreducing conditions, and had 50,000 to 56,000 m.w. major and 35,000 to 38,000 m.w. minor components under reducing conditions. The 110,000 m.w. component, the third component of IL 2R, was constantly observed in 6H2-F9 hybrid cells.

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PubMed1986

Enzyme-linked immunosorbent assay of mouse interleukin-2 receptors.

An enzyme-linked immunosorbent assay (ELISA) which measures soluble mouse interleukin-2 receptor (IL-2R) was developed, using two monoclonal anti-mouse IL-2R antibodies directed against two different epitopes of the IL-2R molecule. The ELISA-reactive material was identical with the IL-2R material which was capable of binding to affinity support beads coupled with recombinant interleukin-2 (IL-2). Quantitation of IL-2R in detergent-lysed cells was compared to that of the purified IL-2R, and the detection limit was estimated to be within the range of 2-10 ng/ml of a test sample. This sensitivity made it possible to determine soluble IL-2R levels in cell culture supernatants and mouse sera.

Animals↗
PubMed1986

B cell-stimulatory factor 1 (BSF-1) promotes growth of helper T cell lines.

T cell-derived supernatants (SN) that contain B cell-stimulatory factor 1 (BSF-1) and lack IL-2 promote the growth of the IL-2-dependent T cell line, HT-2, as well as three other clones or lines of T cells that can provide help to B cells. The BSF-1 purified from these SNs promotes growth of HT-2 cells approximately 50% as effectively as purified IL-2. A potential involvement for contaminating IL-2 in the BSF-1 preparations was excluded by the demonstration that anti-BSF-1 mAbs blocked the BSF-1-induced growth of HT-2 cells; in contrast, these antibodies did not block the IL-2-induced proliferation of the HT-2 cells. In addition, anti-IL-2 mAbs or anti-IL-2-R antibodies blocked the HT-2 growth-promoting activity of purified IL-2, but not BSF-1. Finally, BSF-1 promoted only a very modest growth of Con A-induced T cell blasts, and failed to induce significant growth in seven other cytotoxic, alloreactive, and long-term T cell lines. Taken together, these results indicate that in addition to its known effects on resting and LPS-stimulated B cells, BSF-1 can promote growth of certain subsets of activated T cells, in particular, those that provide help to B cells.

Animals↗
PubMed1986

Administration of group A streptococcal cell walls to rats induces an interleukin 2 deficiency.

Intraperitoneal administration of group A streptococcal cell walls to Lewis rats induces a chronic arthritis, whereas the Fischer strain is resistant to the development of the lesion. Spleen cells from cell wall-treated rats (Lewis and Fischer) are deficient in the synthesis of IL-2. Using an mAb directed against the rat IL-2-R, the present studies indicate that the expression of IL-2-R on spleens of cell wall-treated rats is normal. However, the addition of exogenous IL-2 to spleen cells cultured with Con A does not stimulate the mitogenic response.

Animals↗
PubMed1986

5C6-F4, a novel 100,000-dalton rat lymphocyte activation antigen defined by monoclonal antibody.

Con A-activated rat thymocytes were used to immunize mice, and immune spleen cells were fused with NS/1 myeloma cells. One clone, designated 5C6-F4, reacted strongly with Con A-activated rat thymocytes and some LPS-activated rat spleen cells but not with normal thymocytes, spleen cells, or bone marrow cells of rat origin. The 5C6-F4 did not react with Con A-activated thymocytes of mouse origin. Immunoprecipitation of 5C6-F4 antigen from surface-iodinated Con A-activated rat thymocytes or LPS-activated rat spleen cells revealed its m.w. to be approximately 100,000. The kinetic studies of the expression of 5C6-F4 antigen revealed that 5C6-F4 antigen was detectable at 6 hr after Con A stimulation of rat spleen cells, whereas IL 2 receptor (IL 2R) was detectable at 12 hr. The appearance of 5C6-F4 antigen and IL 2R precede the onset of DNA synthesis of Con A-activated spleen cells. Thus, 5C6-F4 antigen is classified as early activation antigen. The 5C6-F4 inhibits the lymphocyte proliferation induced by mitogen and the IL 2-driven rat T cell proliferation. Sequential immunoprecipitation study as well as binding inhibition study indicated that the 5C6-F4 antigen is distinct from IL 2R molecule. The 5C6-F4 antigen appears to be a novel rat lymphocyte activation antigen that exhibits immunoregulatory function and also may serve as a useful marker of T cell activation.

Animals↗
PubMed1986

Interleukin 2 receptors are released by cells in vitro and in vivo. I. Detection of soluble IL 2 receptors in cell culture supernatants and in the serum of mice by an immunoradiometric assay.

An immunoradiometric assay (IRMA) detecting nanogram amounts of soluble mouse interleukin 2 receptors (IL 2R) is described. The IRMA is based on the finding that the two monoclonal antibodies AMT-13 and 7D4 react with two different epitopes of the mouse IL 2R molecule. As detected by IRMA, T lymphoblasts and IL 2R+ leukemic cells when incubated release IL 2R in soluble form into the culture medium. In the serum of mice inoculated with syngeneic IL 2R+ leukemic cells, growing as a solid tumor, IL 2R were detectable. The results raise the question whether circulating IL 2R are involved in down-regulation of immune responses.

Animals↗
PubMed1986

Suppression of the local graft-vs.-host reaction in rats by treatment with a monoclonal antibody specific for the interleukin 2 receptor.

Local graft-vs.-host reaction (GVHR) was induced in rats by injecting parental cells into young F1 recipients. As a consequence of antigenic stimulation in the course of developing GVHR in the responding lymph nodes, the number of interleukin 2-receptor (IL 2R)-bearing T cells increased from less than 1% up to 10% of the total population. The IL 2R-bearing cells were located mainly in the T cell areas of the reactive lymph nodes. As assessed by the determination of the GVHR indices, treatment of the recipients with anti-T-helper subset-specific mAb (W3/25) or with anti-IL 2R mAb (ART-18) inhibited the GVHR. In parallel, the number of IL 2R-bearing cells was reduced to the normal levels. W3/25 mAb treatment changed the helper/suppressor subset ratio and reduced the number of circulating lymphocytes in the peripheral blood. In contrast, ART-18 mAb treatment did not induce any detectable changes in the subset distribution and it did not affect the number of circulating lymphocytes. The results demonstrate the key role that the IL 2R-positive cells play in the proliferative phase of acute GVHR, and favor the use of anti-IL 2R mAb as selective immunosuppressive agents.

Animals↗
PubMed1986

Monoclonal antibody-recognizing cone visual pigment.

Monoclonal antibodies were raised to a crude photoreceptor-membrane suspension from chicken retinas. Clones producing antibodies against cone outer segments were selected by screening with immunocytochemistry on semithin sections of the retina. One monoclonal antibody, called COS-1, specifically labelled outer segments of double cones and one type of single cones; outer segments of rods and several single cones were not stained. On immunoblots of retinal photoreceptor membranes, this antibody recognized a protein with an apparent molecular mass of 33,000. The visual pigment character of the 33,000 protein was indirectly established by another monoclonal antibody, OS-2, which labelled all outer segments on semithin sections and four bands (33,000-, 36,000-, 38,000-40,000- and a composite band between 66,000-72,000 MW) on immunoblots. Of these, the 36,000- and the 72,000 MW protein bands were identified with an anti-rhodopsin polyclonal antibody as rhodopsin monomer and dimer. Monoclonal antibody OS-2 is assumed therefore to represent an antibody against a common epitope of all visual pigments of the chicken. The monoclonal antibody COS-1 was found to bind to certain cone outer segments of many other vertebrate species as well.

Animals↗
PubMed1986

Regulation of interleukin-2 receptor expression and receptor release.

The generation and cell surface expression of IL-2 receptors was monitored by: (i) an ELISA that permits quantitative determination of detergent-solubilized or soluble IL-2 receptors; and (ii) detection of the binding of 125I-labelled recombinant IL-2 and of anti-IL-2 receptor antibodies to receptor bearing cells. Upon lectin stimulation both high and low affinity IL-2 receptors became expressed in parallel at the cell surface. Both high and low affinity receptors were upregulated by IL-2. Upon lectin activation the amount of cell-associated receptors increased and on day 2 of the culture period IL-2 receptors were detectable in the culture supernatant. IL-2 upregulated both high and low affinity IL-2R expression on T-lymphoblasts. IL-2R bearing leukemic cells and T lymphoblasts released IL-2R when cultured in vitro. IL-2R release by T lymphoblasts was enhanced dramatically by IL-2. On the other hand, IL-2-receptor positive leukemic cells released receptors in an IL-2 independent manner. Release of receptors could also be detected in serum-free medium. At least a part of the released receptors could be specifically bound to immobilized pure recombinant IL-2 and to monoclonal anti-IL-2-receptor antibodies. Small but significant amounts of soluble IL-2 receptors were detectable in the sera of normal mice. In sera of mice inoculated with IL-2-receptor positive syngeneic leukemic cells, elevated levels of IL-2 receptors were detectable. Release of IL-2 receptors seems to represent one of the major routes by which the receptors are cleared from the cell surface.

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