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Query: UNIPROT:P06889 (Mol)
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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.
Mol Immunol 1986 Nov
PMID:Regulation of interleukin-2 receptor expression and receptor release. 310 50

A recombinant amphotropic retrovirus was used to introduce the protein-coding region of the IL-2 receptor cDNA derived from HUT-102 cells into human CEM leukemic T-cells that lack these receptors. CEM T-cells that contained the virus expressed functional IL-2 receptors that transiently mediated five- to tenfold increases in [3H]thymidine incorporation following the addition of picomolar quantities of IL-2. Although IL-2 responsiveness was subsequently lost, it could be reinduced by cellular activation with the OKT11 monoclonal antibody. This phenotype also proved unstable with progressive time in culture. Despite the loss of IL-2 responsiveness, the infected CEM T-cells continued to express Tac antigen and displayed 50 to 200 high-affinity IL-2 receptors per cell that bound IL-2 with a dissociation constant of 4.3 pM. This affinity is fully equivalent to that detected on activated normal T-cells (2 to 50 pM). The apparent molecular size of the Tac antigen on these cells (55,000 to 60,000 daltons) was comparable to that on normal activated T-cells but 5000 daltons larger than the aberrant IL-2 receptors on HUT-102 cells. These data demonstrate that expression of a human IL-2 receptor cDNA in human T-cells results in high-affinity IL-2 receptor display that transiently imparts an IL-2 responsive state of growth. These results also raise the possibility that the T11 surface receptor may play an important regulatory role in high-affinity IL-2 receptor expression.
Mol Biol Med 1987 Apr
PMID:Reconstitution of high affinity IL-2 receptor expression in a human T-cell line using a retroviral cDNA expression vector. 311 93

Human testicular cytosol and ovarian follicular fluid were analyzed for the presence of interleukin-1 (IL-1)-like factors. Both the follicular fluid and testis cytosol preparations exhibited significant IL-1-like activity as determined by the murine thymocyte proliferation bioassay. The dose-response lines obtained with the gonadal preparations were parallel to each other and to those obtained with monocyte-derived IL-1 and the activity of the gonadal IL-1 could be neutralized by specific IL-1 antibodies. After gel chromatography of human follicular fluid (hFF) and human testis cytosol (hTC) proteins, IL-1 activity was found in the molecular weight region between 30 and 50 kilodaltons (kDa). Chromatofocusing of IL-1 from hFF and hTC revealed that the major part of IL-1 in both cases exhibited similar charge properties (pI less than 6.0). However, two extra peaks (pI 7.0 and greater than 9.0, respectively) were observed in hFF preparations. After isoelectrofocusing (IEF), IL-1 activity of hFF was also found in two different pH regions; a broad area of activity was localized between pH 5.5 and 7.0, while a sharp peak was observed with an approximate pI value of 9.5. Re-chromatofocusing or IEF of alkaline IL-1-like activity resulted in a heterogeneous profile of IL-1-like activity suggesting that the alkaline material may represent either a precursor or an aggregated form of the acidic IL-1. None of the IL-1 peaks obtained from hFF or hTC exhibited IL-2 activity as assessed in a specific IL-2 bioassay. The results of the present study indicate that both gonads may produce high amounts of IL-1-like factor(s) which might play a regulatory role in normal gonadal function.
Mol Cell Endocrinol 1988 Aug
PMID:Human testis cytosol and ovarian follicular fluid contain high amounts of interleukin-1-like factor(s). 326 98

An I-Ab-restricted, L3T4+ Ly2- T-cell clone, 5R-4F3, specific for ABAtyr was established in culture from a B10.A(5R) mouse. Since b haplotype mice respond weakly to ABAtyr compared to other haplotypes, this is a candidate clone of low responder phenotype. In support of this contention, 5R-4F3 grew very poorly under conditions that supported the vigorous growth of E beta bE alpha k-restricted T-cell clones from the same mouse. The I-A (low responder) and I-E (high responder) restricted T-cell clones also differed in their responses to apc pre-pulsed with antigen, compared to apc with antigen present continuously during culture. The low and high responder clones responded comparably to IL-2. Attempts to elevate the response of C57BL/6 mice to ABAtyr in vivo by injecting them with human recombinant IL-2 and antigen together were only partially successful: C57BL/6 mice treated in this way showed a 3-5-fold increase in their proliferative responses to ABAtyr, which was at best only one quarter of the level of response shown by high responder A/J mice to the same antigen dose.
Mol Immunol 1988 Nov
PMID:The murine T-lymphocyte response to tyrosine-azobenzenearsonate. Characteristics of a low responder haplotype T-cell clone. 326 81

A semi-synthetic protein design approach has been employed for the structural investigation of a putative helical region at the C-terminus of Interleukin-2. With crystallographic or NMR derived conformational data as yet unavailable, we have relied only on primary sequence information and computer-assisted modelling to direct the analysis. By employing both chemical peptide synthesis and recombinant DNA methods, the C-terminus of IL-2 was modified according to a strategy designed to stabilize helical secondary structure. A semi-synthetic protein incorporating 12 simultaneous amino acid replacements was constructed, which possessed potentiated biological activity and displayed a far UV circular dichroism spectrum comparable to a hybrid protein with the authentic sequence. By comparison, another hybrid protein containing a C-terminal region designed to contain helix breaking residues was totally devoid of bioactivity. These findings provide evidence that the modelling method correctly identified a helix necessary for the formation of a bioactive tertiary fold. Moreover, by employing semi-synthesis it was possible to circumvent the difficulties associated with the preparation, purification and analysis of multiple recombinant proteins, and also to avoid the unreliability of total chemical synthesis for proteins greater than 100 residues.
J Mol Recognit 1988 Feb
PMID:A design approach to the structural analysis of interleukin-2. 327 51

The precise molecular characteristics and the mode of action of the T cell derived lymphokines which augment antibody production in vitro remain uncertain. The use of ill-defined culture supernatants to dissect the cellular interactions in vitro involved in antibody production can lead to ambiguous results as the factors may act either on a contaminating non-B-lymphoid population or directly on the B lymphocyte. We report herein the development of a system for measuring in vitro primary antibody responses by murine spleen cells in which endogenous lymphokine production has been minimized by the in vivo administration of cytotoxic antibodies to deplete T lymphocytes and the addition of the glucocorticosteroid, dexamethasone, throughout the culture period. Using such an assay, a lymphokine activity was detected which was capable of augmenting the plaque forming cell response. This lymphokine was present in culture supernatant derived from the lectin activation of the T cell lymphoma, LBRM-33 and was distinct from other known B cell activators, notably IL-2 and IFN gamma. Biochemical purification of this activity indicated that it might be identical to granulocyte-macrophage colony stimulating factor (GM-CSF). The use of recombinant-derived GM-CSF protein unambiguously showed the role of this lymphokine in antibody production. These experiments demonstrated for the first time, the involvement of a hematopoietic factor in antigen-specific immune responses. Moreover, these results demonstrated an important regulatory circuit in the generation of antibody producing B cells in which GM-CSF, derived from activated T cells, stimulates macrophage function.
J Mol Cell Immunol 1986
PMID:Regulation of antibody production in vitro by granulocyte-macrophage colony stimulating factor. 333 16

By screening several cytolytic T-lymphocyte lines, AKR thymomas, and CTL X AKR thymoma hybrids from two different crosses for their sensitivity to the glucocorticoid (GC) analog dexamethasone (dex), we have found that CTL lines and cytolytically active, IL-2-dependent (CTL-like) hybrids are resistant to the cytostatic or cytolytic effects of dex; AKR thymomas and thymoma-like hybrids (cytolytically inactive, IL-2-independent), however, are sensitive to these effects of the drug. The GC resistance behaves like a dominant trait in these crosses. Although they are resistant to GC, the CTL lines and the CTL-like hybrids do contain functional hormone receptors and macrophage-activating factor (MAF) release by the CTL lines and CTL-like hybrids is inhibited by dex.
Somat Cell Mol Genet 1985 Nov
PMID:Glucocorticoid resistance is a dominant trait in hybrids between cytolytic T-lymphocyte lines and AKR thymomas. 387 92

Molecular weight and charge microheterogeneity of Thy-1 glycoprotein expressed on different T-cell populations were compared by two-dimensional gel electrophoresis and endoglycosidase treatment. Thy-1 was immunoprecipitated from detergent lysates of radioiodinated T-cells of spleens, lymph nodes, Peyer's patches, peripheral blood, IL-2-cultured thymocytes and peanut agglutinin (PNA) separated thymocytes. In general, thymocytes and IL-2-cultured thymocytes expressed the highest levels of Thy-1 with a large Mr and charge variation. The Thy-1 of these cells was basic and contained low levels of sialic acid. On the other hand, peripheral T-lymphocytes exhibited a restricted Mr and more limited charge heterogeneity with higher amounts of sialic acid. The Thy-1 glycoprotein of mature, low Thy-1 PNA- thymocytes had Mr and charge heterogeneity identical to peripheral T-lymphocytes. The Mr and charge variation of immature PNA+ thymocytes was essentially identical to that of whole thymocytes. The molecular source of Mr heterogeneity in thymocyte Thy-1 and restricted Mr in lymph node Thy-1 was studied by analysis with endoglycosidase-H (Endo-H) and Endo-D. The results of Endo-H digestion showed that most of the Thy-1 polypeptides from both thymocyte and lymph node contained one high-mannose type oligosaccharide which was relatively small and not heterogeneous with respect to Mr. The complex-type oligosaccharides (Endo-D-sensitive) were larger and were responsible for the broad Mr-heterogeneity found in thymocyte Thy-1. Both thymocyte and lymph node Thy-1 generally appear to contain three N-linked oligosaccharides (one high-mannose and two complex) and sequential hydrolysis with Endo-H and Endo-D resulted in an unglycosylated polypeptide with an Mr of approx. 12,500.
Mol Immunol 1984 May
PMID:Molecular weight and charge heterogeneity of Thy-1 glycoprotein in different populations of T-cells. 614 94

Although lymphokine producing helper T cells are suspected to play an important role in the development of anti-viral cytotoxicity, they have not previously been demonstrable in influenza virus-primed mice unless the mice have first been pretreated with cyclophosphamide. It has been assumed that cyclophosphamide pretreatment was required to block the activities of suppressor cells which would otherwise interfere with helper T cell priming. We have developed a limiting dilution assay (LDA) for estimating influenza virus-specific T cell precursors for IL-2 secretion ("pHTL"), and have found that equal numbers of pHTL develop in virus-primed mice regardless of cyclophosphamide pretreatment. This result suggests that the cyclophosphamide-sensitive regulatory cells do not act in vivo to prevent helper cell priming, but rather act in vitro to oppose expression of helper cell activity. Comparison of helper cell function in conventional (high density) cultures and in LDA cultures reveals an Lyt-2+ cell which prevents development of cytotoxic function in conventional assays, but which fails to affect the outcome of the LDA experiments. We found that the pHTL population consists almost entirely of Lyt-2- cells, and that mice primed with the Type A strain, PR/8, develop pHTL responsive to a wide range of influenza viruses, including a Type B strain. Both results modify conclusions suggested by conventional assay methods. Since the LDA experiments seem to be relatively resistant to regulatory interactions which can influence the outcome of standard assay cultures, they can supply information about the characteristics of the pHTL itself that would otherwise be difficult to obtain.
J Mol Cell Immunol 1984
PMID:Limiting dilution cultures reveal latent influenza virus-specific helper T cells in virus-primed mice. 624 62

The four Ia polypeptides in mice, A alpha, A beta, E beta, and E alpha, are expressed predominantly on B lymphocytes and certain macrophage populations. Whether T lymphocytes express Ia antigens has been controversial. Although Ia antigens have been demonstrated on small populations of mitogen-activated and alloreactive lymphocytes, the T cell origin of these Ia antigens has been doubted. It has been suggested that Ia antigens on T cells are passively acquired from non-T lymphocytes. The present study analyzes the endogenous synthesis and expression of Ia antigens by an alloreactive-derived T cell clone. This clone, PLT-24.2.Cl, was derived initially from an alloreactive cell population, B6 anti-B10.K. The cell line was cloned by limiting dilution and maintained by periodic boosting with the stimulator cells. After 4 months of sequential boosting, it was possible to maintain the cloned cells in the absence of irradiated B10.K filler spleen cells. It has now been in culture for over a year in the absence of both filler cells and exogenous growth factors (e.g., IL-2). The expression of Ia antigens on the cell surface of the cloned T cell line was detected by using monoclonal antibodies and cytofluorometry. The cloned cells were positive for Thy.1, Lyt.1, and Lyt.2, and negative for surface immunoglobulin. The cells expressed all of the Ia antigens normally found on an I-Ab derived cell, i.e., Ia.8 and Ia.15, and lacked Ia.7. The cells lacked any of the Ia antigens expressed on the original stimulator cells, B10.K. These results show that PLT-24.2.Cl expresses syngeneic Ia antigens. The endogenous synthesis of Ia antigens by these cell lines was confirmed by biosynthetic labeling with radiolabeled amino acid precursors and indirect immunoprecipitation on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The Ia antigens synthesized by the T cell clone are structurally identical to those synthesized by the syngeneic B lymphocytes, as shown by tryptic peptide mapping using high-pressure liquid chromatography. These studies prove that the Ia antigens predominantly expressed on B lymphocytes and some macrophage-derived cells can also be synthesized and expressed by T lymphocytes. Since Ia antigens are involved in numerous immune phenomena and cell-cell interactions, this information would have to be taken into account in proposing mechanisms by which Ia-restricted helper and suppressor cells are generated.
J Mol Cell Immunol 1984
PMID:Endogenous synthesis of Ia antigens by a cloned T cell line. 633 92


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