Blockade of the interleukin-2 receptor by anti-Tac antibody inhibits the generation of antigen-nonspecific suppressor T cells in vitro.

The role of interleukin 2 (IL-2) in the activation of suppressor T cells was investigated by using the monoclonal antibody anti-Tac, which blocks the binding of IL-2 to the 55-kDa peptide of the high-affinity IL-2 receptor. Anti-Tac was added to an antigen-nonspecific suppressor system in which Con A-induced suppressor T cells were generated during a preculture period, and their effects on immunoglobulin production were assessed in second, indicator cultures containing pokeweed mitogen and peripheral blood mononuclear cells. Anti-Tac added during the preculture period inhibited Con A-induced suppressor T-cell generation.

Lateral diffusion measurements give evidence for association of the Tac peptide of the IL-2 receptor with the T27 peptide in the plasma membrane of HUT-102-B2 T cells.

Fluorescence photobleaching recovery measurements show that the F1-IgG-labeled Tac peptide of the IL-2R can diffuse in the plane of the membrane of HUT-102-B2 T lymphocytes, with a mean diffusion coefficient of 2 to 3 x 10(-10) cm2s-1. Although only a fraction (mean 37%) of the Tac peptides is mobile on any given cell, lateral diffusion of the Tac peptide can be measured in 94% of cells examined. In contrast, the 95-kDa peptide, T27, is 90 to 100% immobilized in cells labeled with OKT27.

Polyclonal nature of the intestinal mucosal lymphocyte populations in inflammatory bowel disease. A molecular genetic evaluation of the immunoglobulin and T-cell antigen receptors.

To define the clonality of the intestinal lymphocytes involved in the immune response of inflammatory bowel disease, we performed a molecular genetic analysis of the arrangement of the immunoglobulin and antigen-specific T-cell receptor genes of isolated lamina propria lymphocytes derived from resected intestinal specimens of 12 patients with Crohn's disease, 5 patients with chronic ulcerative colitis, and 7 patients with other gastrointestinal diseases. The sensitivity of this technique is sufficient to detect a monoclonal population when there is as little as 1% clonal expansion in a mixed cell population. In all these groups of patients, deoxyribonucleic acid from the non-T cells demonstrated only a germ-line gene pattern, and no non-germ-line rearrangements of immunoglobulin genes as assessed by an immunoglobulin-joining heavy-chain gene probe.

Immunoglobulin and T cell antigen receptor gene arrangements indicate that the immune response in autoimmune thyroid disease is polyclonal.

To further define the degree of heterogeneity of the antibody and cellular immune responses in autoimmune thyroid disease, we used Southern blot hybridization techniques to analyze the arrangements of immunoglobulin and T cell antigen receptor genes in circulating lymphocytes and in those infiltrating the thyroid gland in nine patients with thyrotoxicosis due to Graves' disease and five patients with Hashimoto's thyroiditis. The sensitivity of these techniques was sufficient to detect a monoclonal population when there was as little as 1% clonal involvement in a mixed cell population. In the patients studied, DNA from non-T peripheral blood cells and non-T intrathyroid lymphocytes had only a germline gene pattern and no clonal nongermline rearrangements of immunoglobulin genes, as assessed using an immunoglobulin joining heavy chain (IgJH) gene probe.

In vitro suppression of anti-DNA antibody and immunoglobulin synthesis in systemic lupus erythematosus patients by human gamma interferon.

The immunoregulator human gamma interferon (IFN-gamma) suppressed the spontaneous in vitro synthesis and secretion of anti-DNA antibodies by peripheral blood mononuclear cells of patients with systemic lupus erythematosus (SLE-PBMC). Comparable level of suppression were observed with both natural human IFN-gamma and recombinant derived human IFN-gamma. In addition, the inhibitory effects of human IFN-gamma were completely neutralized by a monoclonal antibody directed against it.

Induced net Ca(2+) uptake and callose biosynthesis in suspension-cultured plant cells.

In suspension-cultured cells of Glycine max and Catharanthus roseus, marked callose synthesis can be induced by digitonin and chitosan. Leakage of a limited pool of electrolytes precedes callose formation, K(+) representing the major cation lost. Poly-L-ornithine, as well as the ionophores A 23187 and ionomycin, also induces some callose synthesis but to a lesser extent.

Large granular lymphocyte proliferation: an analysis of T-cell receptor gene arrangement and expression and the effect of in vitro culture with inducing agents.

The status of the T cell receptor beta and gamma genes in natural killer (NK) cells was investigated in two patients with a marked expansion of CD2+, CD3- NK cells. Both genes were found to be in the germline state. The T alpha and complete T beta gene transcripts were not detected, but a 1.

The role of the multichain IL-2 receptor complex in the control of normal and malignant T-cell proliferation.

Antigen-induced activation of resting T cells induces the synthesis of interleukin-2 (IL-2), as well as the expression of specific cell surface receptors for this lymphokine. There are at least two forms of the cellular receptors for IL-2, one with a very high affinity and the other with a lower affinity. We have identified two IL-2 binding peptides, a 55-kd peptide reactive with the anti-Tac monoclonal antibody and a 75-kd non-Tac IL-2 binding peptide.

Deletional rearrangement in the human T-cell receptor alpha-chain locus.

The antigen-specific receptor on the surface of mature T lymphocytes is a heterodimer consisting of polypeptides termed alpha and beta. In the course of characterizing human T-cell tumors with an immature (CD4-, CD8-) surface phenotype, we detected a 2-kilobase alpha-related transcript. Analysis of cDNA clones corresponding to this transcript established that a genetic element (which we call TEA, for "T early alpha") located between the alpha-chain variable- and joining-region genes had been spliced to the alpha constant region.

The role of the multichain IL-2 receptor complex in the control of normal and malignant T-cell proliferation.

Antigen-induced activation of resting T-cells induces the synthesis of interleukin-2 (IL-2), as well as the expression of specific cell surface receptors for this lymphokine. There are at least two forms of the cellular receptors for IL-2, one with a very high affinity and the other with a lower affinity. We have identified two IL-2 binding peptides, a 55-kd peptide reactive with the anti-Tac monoclonal antibody, and a novel 75-kd non-Tac IL-2 binding peptide.

Type I and II insulin-like growth factor receptors on human phytohemagglutinin-activated T lymphocytes.

Human T cells activated with mitogens, antigens, or antibodies to the T-cell receptor complex acquire a cascade of new receptors, including the receptors for interleukin-2, transferrin, and insulin. We investigated whether receptors for insulin-like growth factors (IGF) also were expressed on activated T cells. Based on competitive binding studies, immunoprecipitation of labeled cell surface receptors and blocking of radiolabeled peptide binding by a specific monoclonal antibody (alpha IR-3) to the type I IGF receptor, as well as affinity crosslinking of radiolabeled peptides to their receptors, we concluded that both type I and type II IGF receptors are expressed on activated T cells.

Flow cytometric resonance energy transfer measurements support the association of a 95-kDa peptide termed T27 with the 55-kDa Tac peptide.

Two monoclonal antibodies (OKT27 and OKT27b) have been produced that react with distinct epitopes of a 95-kDa peptide. The T27 antigen is widely distributed, being expressed on B lymphocytes, monocytes, and adult T-leukemic cells but not on polymorphonuclear leukocytes or platelets. There was a low level of T27 expression on resting T cells that increased on T-cell activation.

The p75 peptide is the receptor for interleukin 2 expressed on large granular lymphocytes and is responsible for the interleukin 2 activation of these cells.

There are at least two interleukin 2 (IL-2) binding peptides: one is the Mr 55,000 peptide (p55) reactive with the anti-Tac monoclonal antibody, and the other is a Mr 75,000 non-Tac IL-2 binding peptide (p75). Independently existing Tac or p75 peptides represent low-affinity IL-2 receptors, whereas high-affinity IL-2 receptors are expressed when both peptides are present and associated in a receptor complex. It has long been known that normal large granular lymphocytes (LGL) or leukemic cells from the patients with abnormal expansions of LGL can be activated by IL-2 not only to more-potent natural killer cells but also to effectors of lymphokine-activated killer (LAK) activity, although they do not express the Tac peptide.

Contribution of a p75 interleukin 2 binding peptide to a high-affinity interleukin 2 receptor complex.

There are at least two forms of cellular receptors for interleukin 2 (IL-2); one with a very high affinity and the other with a lower affinity. We identified a non-Tac IL-2 binding peptide with a relative molecular weight of 75,000 (p75). Cell lines bearing either the p55 Tac or the p75 peptide alone manifested low-affinity IL-2 binding, whereas a cell line bearing both peptides manifested both high- and low-affinity receptors.

Expression of functional IL 2 receptors by lipopolysaccharide and interferon-gamma stimulated human monocytes.

Human peripheral blood monocytes were stimulated with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) alone or in combination. Stimulated but not resting monocytes displayed the Tac peptide of the interleukin 2 (IL 2) receptor within 24 hr as measured by immunofluorescence staining and [3H] Tac binding. The total number of anti-Tac binding sites on co-stimulated monocytes was 13,700.

The arrangement of immunoglobulin and T cell receptor genes in human lymphoproliferative disorders.

Immunoglobulin and T cell antigen receptor genes in their germ-line form are organized as discontinuous DNA elements that are joined by recombinations during lymphocyte development. The analysis of immunoglobulin gene structure and arrangement has been of great value in the study of human lymphoid neoplasms. The analysis of rearranged immunoglobulin and T cell receptor genes has been of value in defining the lineage (T or B cell) of neoplasms that were of controversial origin previously, determining the clonality of abnormal lymphocyte proliferations, diagnosing and monitoring the therapy of lymphoid malignancies, determining the state of maturation and the causes for failure of maturation of cells of the B cell series, and providing major insights into the cause of malignant transformation of B and T lymphoid cells.

The interleukin-2 receptor on normal and malignant lymphocytes.

Interleukin-2 (IL-2) is a lymphokine synthesized by T cells following activation. Resting T cells do not express IL-2 receptors, but receptors are rapidly expressed on T cells following interaction of the antigen-specific T-cell receptor complex with appropriately processed and presented antigens. Anti-Tac, a monoclonal antibody that recognized the IL-2 receptor, has been used to purify the receptor.

Demonstration of a non-Tac peptide that binds interleukin 2: a potential participant in a multichain interleukin 2 receptor complex.

The interleukin 2 (IL-2) receptor system plays a key role in the T-cell immune response. Although IL-2 binding was reported to be restricted to the Tac peptide, we have identified an IL-2 binding peptide that does not react with anti-human IL-2 receptor monoclonal antibodies, including anti-Tac on MLA 144, a gibbon ape T-cell line. The MLA 144 cell line expressed 6800 IL-2 binding sites per cell with a low (Kd = 14 nM) affinity for human recombinant IL-2.