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J Trial

Publications and source records attributed to J Trial.

33 records · Page 2Linked to original sources
PubMed1988

CD8+ T cells lyse autologous monocytes in the presence of anti-CD3 monoclonal antibody: association with interleukin-1 production.

Human peripheral blood T cells lysed autologous or allogeneic monocytes, but not polymorphonuclear cells (PMN) or lymphocytes, in the presence of anti-CD3 (OKT3 (IgG2a) or anti-Leu 4 (IgG1)) monoclonal antibody (mAb). Other mAbs such as OKT4 (IgG2b), OKT8 (IgG2a), OKT11 (IgG2a), and OKM1 (IgG2a) did not mediate lysis of monocytes. Lysis of monocytes also did not occur in the presence of F(ab')2 fragments of OKT3 mAb. OKT3 mAb and control murine IgG2a mAb, but not F(ab')2 fragments of OKT3 mAb, were bound to the monocyte cell surface. Purified human IgG1 and IgG3 myeloma proteins, polyclonal human IgG, or Con A inhibited anti-CD3-dependent T-cell cytotoxicity against monocytes when added to the 4-hr 51Cr-release assay. Pretreatment of monocytes with an irrelevant murine IgG2a mAb also inhibited OKT3 mAb (IgG2a)-dependent lysis of these cells, but did not affect anti-Leu 4 mAb (IgG1)-dependent lysis, suggesting that two different Fc receptors were involved. These results strongly suggest that Fc IgG receptors on monocytes are a critical structure for anti-CD3-dependent cytotoxicity. Lysis of monocytes was accompanied by interleukin-1 (IL-1) production, which was detected in supernatants from 4-hr cultures of T cells and monocytes in the presence of the OKT3 mAb. Both anti-CD3-dependent lysis of monocytes and IL-1 production were severely decreased after treatment of T cells with either OKT3 or OKT8 mAb plus complement, but were not affected significantly by treatment with the OKT4 mAb plus complement. Purified CD8+ cells, prepared using the cell sorter, exhibited significant levels of anti-CD3-dependent monocyte lysis (greater than 10%). In contrast, purified CD4+ cells did not exhibit significant levels of anti-CD3-dependent cytotoxicity (less than 10%). Production of high concentrations of IL-1 was observed in cultures of purified CD8+ cells and monocytes in the presence of anti-CD3 mAb. Only low concentrations of IL-1 were detected in cultures of purified CD4+ cells, monocytes, and OKT3 mAb. These results suggest that CD8+ cells are primarily responsible for lysis of monocytes, which is associated with IL-1 production. It appears that anti-CD3 mAb brings CD8+ T cells and monocytes into close proximity by binding to the CD3 antigen on T cells and to the Fc IgG receptor on monocytes. This interaction results in lysis of monocytes primarily by CD8+ cells, after bypassing any antigen recognition requirements that may be otherwise needed. Lysis of monocytes appears to be associated with IL-1 release.

Adult↗
PubMed1988

Prostaglandin production by human promyelocytic leukemia (HL-60) cells.

A comparative analysis of prostaglandin production was carried out on human promyelocytic leukemia (HL-60) cells treated with either PMA or DMSO. When incubated with [1-14C]arachidonic acid these cells produced significant amounts of 6-keto prostaglandin F1 alpha, thromboxane B2, prostaglandin F2 alpha, prostaglandin E2, prostaglandin D2 and 12-hydroxy-5,8,10-heptadecatrienoic acid via the cyclooxygenase pathway. The major cyclooxygenase metabolite synthesized by these cells was prostaglandin F2 alpha. Its production increased significantly when the HL-60 cells were treated with PMA and decreased when treated with DMSO as compared to untreated control cells. This change in the production of prostaglandin F2 alpha appears to reflect alterations in cyclooxygenase activity. Another unidentified arachidonic acid metabolite was routinely observed in C18 high pressure liquid chromatography. The synthesis of this compound was inhibited by indomethacin. The unidentified metabolite was also seen in the human macrophage-like cell line U937.

Arachidonic Acid↗
PubMed1988

Bovine aorta endothelial cell incubation with interleukin 2: morphological changes correlate with enhanced vascular permeability.

Interleukin 2 induced alterations in the morphology of bovine aortic endothelial cells in vitro. The changes observed in confluent cultures of bovine aortic endothelial cells included retraction and elongation of cells leading to enlarged gaps between cells quantified by image analysis. Purified IL-2 (1 U/ml medium) increased the gaps between endothelial cells 3-4-fold compared with control cultures. The effect was transient, since the cells reverted to their original morphology 6-12 hours after the removal of IL-2. Correlative scanning electron microscopy (SEM) studies using fresh bovine aorta showed a dose-dependent alteration of the endothelial surface by IL-2 characterized by rounding and elongation of endothelial cells and prominent perinuclear areas. Gaps between the endothelial cells were observed when aorta samples were incubated with 2 U of IL-2/ml of medium. This was confirmed by SEM, transmission electron microscopy and Evans blue dye staining. These results suggest that IL-2 caused morphological alterations in endothelial cells that enhanced the permeability of the vascular endothelium.

Animals↗
PubMed1986

Structure and expression of Fc gamma receptors on mouse suppressor T cell hybridomas.

Antigen-specific and idiotype-specific mouse suppressor T cell hybridomas were analyzed for the presence and specificity of Fc gamma receptors (Fc gamma R) by EA rosetting and by flow microfluorometry with the use of monoclonal antibodies. We found that four hybridomas expressed Fc gamma R specific for IgG1 and IgG2b, one of which became Fc gamma R- during prolonged culture. Four other hybridomas and the fusion parent, BW5147, consistently lacked Fc gamma R. The 125I-labeled Fc gamma R were isolated from surface radioiodinated hybridoma cells solubilized with 1% Nonidet P-40, were purified by using single or repetitive chromatography on mouse IgG-Sepharose columns, and were analyzed by SDS-PAGE. An 125I-labeled 56,000 to 61,000 Mr macromolecule was isolated from each of the Fc gamma R+ hybridomas, but from none of the Fc gamma R- hybridomas nor from BW5147 cells. This macromolecule rebound to insolubilized mouse IgG1, IgG2b, and human Fc fragments, but not to insolubilized mouse IgG2a, IgG3, or IgA or human F(ab')2 fragments, consistent with the specificity observed for Fc gamma R on intact hybridoma cells. The mouse suppressor T cell Fc gamma R differs in size and specificity from mouse B cell Fc gamma R. A 70,000 Mr protein expressed on all hybridomas and on BW5147 cells was radiolabeled and, despite preclearing with ovalbumin-Sepharose, bound to the mouse IgG-Sepharose columns, presumably due to mouse antibodies to gp-70. This macromolecule was completely and specifically removed by using goat antiserum to gp-70.

Animals↗
PubMed1986

Effect of serotonin on murine macrophages: suppression of Ia expression by serotonin and its reversal by 5-HT2 serotonergic receptor antagonists.

Serotonin (5-HT), a mediator released from platelets at sites of inflammation, suppressed IFN-gamma-induced Ia expression in mouse bone marrow macrophages maintained in vitro. (Mean percent suppression = 63.9% +/- 9.2, n = 40.) This suppression was not toxic or endotoxin-related, was concentration-dependent, and occurred at the physiologic concentrations of 5-HT present at inflammatory sites. The concentration of 5-HT producing the half-maximal effect was 2.5 to 5.5 X 10(-8) M. Related compounds, dopamine, histamine, and tryptamine, were much less potent in suppressing IFN-gamma-induced Ia, with maximally suppressing concentrations more than 100-fold higher than the maximally suppressing 5-HT concentration. L-5-hydroxytryptophan (5-HTP), the most potent analog tested, was 10-fold less potent than 5-HT in suppressing Ia expression. The concentration of 5-HTP producing the half-maximal effect = 4 X 10(-7) M. 5-HT suppression of IFN-gamma-induced Ia expression was antagonized by the 5-HT2 type receptor antagonists spiperone, ketanserin, and LY53857. Concentrations of these agents resulting in 50% inhibition of the serotonin effect were 1.5 X 10(-8) M, 7.5 X 10(-8) M, and 4.5 X 10(-12) M, respectively. 5-HT was most effective in suppressing IFN-gamma-induced Ia when added early in culture simultaneously with IFN-gamma. These data provide functional evidence that 5-HT suppression of IFN-gamma-induced Ia expression is mediated through a 5-HT receptor with some characteristics of the 5-HT2 type. 5-HT may play a physiologic role at sites of inflammation as a modulator of the effects of IFN-gamma on macrophage function.

Animals↗
PubMed1986

TMA-specific first-order T-suppressor hybridoma. I. Characterization of the hybridoma-derived single-chain inducer suppressor factor, TsF1.

Experiments described in this report will characterize a monoclonal phenyltrimethylammonium (TMA) specific, first-order T-suppressor factor (TsF1) produced by a T-cell hybridoma, 8A.3. The hybridoma expressed the Thy-1, Lyt-1, Lyt-2 antigens as well as cross-reactive idiotypic (CRI) determinants but did not express I-J encoded epitopes. It was also found to bear determinants recognized by a monoclonal antibody raised against single-chain GAT-specific TsF1. The hybridoma-derived factor was capable of suppressing primary in vitro trinitrophenol (TNP)-specific responses induced with the Brucella abortus antigen, conjugated with TMA and TNP haptens (TMA-BA-TNP). In addition, in vivo administration of 8A.3 culture supernatant resulted in the specific suppression of TMA-specific delayed-type hypersensitivity (DTH) responses. Analysis of this factor revealed it to be an induction-phase, antigen-binding, CRI+, and I-J+ single chain polypeptide. Our results represent only the second such described single chain, antigen binding, I-J+ suppressor factor derived from a monoclonal T-cell hybridoma.

Animals↗
PubMed1986

Reversibility of vitamin D-induced human leukemia cell-line maturation.

HL-60 cells are induced to differentiate along a monocytic pathway by the active metabolites of vitamin D3, e.g. 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]. All such differentiated cells share a number of features in common but are heterogeneous in their ability to adhere to solid substrates and to resorb devitalized bone matrix. Here, we show that, in addition, as compared to the nonadherent, adherent cells are smaller, less likely to be in the S phase, more enriched in the human monocyte-specific cell surface antigen, 63D3, and contain less cmyc messenger RNA (mRNA). In addition, we document that removal of the hormone leads to dedifferentiation. For these susceptible mononuclear cells, removal of 1,25-(OH)2D3 results in a reversion to a more myeloblastic phenotype, renewed cell proliferation, and the rapid appearance of elevated levels of cmyc mRNA. Finally, we report that the cells that do not revert upon 1,25-(OH)2D3 removal are those that became multinucleated during treatment.

Antigens, Surface↗
PubMed1986

Lymphokines regulate expression of cell surface antigens and production of suppressor factors by murine suppressor T cell hybridomas.

Suppressor T cell hybridomas specific for L-glutamic acid 60-L-alanine30-L-tyrosine10 (GAT) elaborate monoclonal suppressor factors (TsF) and bear surface markers such as H-2, I-J, and Thy-1 antigens. Over a period of years in culture, the production of TsF by such hybridomas has been constitutive and continuous; by contrast, the expression of surface markers has declined and some have been lost. The mixture of lymphokines in the supernatant fluid from concanavalin A-activated mixtures of allogeneic splenocytes (CAS) restored surface antigen expression, and the effective agents have been identified by using purified sources of lymphokines. Murine gamma interferon (IFN gamma) induced expression of H-2 class I antigens, but not I-J or Thy-1, in the hybridoma cells. Human interleukin 2 (IL-2) induced the increased expression of I-J and Thy-1 but not H-2 class I antigens. Interestingly, production of TsF was decreased by IFN gamma treatment but increased by IL-2, indicating some measure of regulation by lymphokines of the level of a protein that is constitutively produced.

Animals↗
PubMed1984

T cell subsets in (responder x nonresponder)F1 mice regulating antibody responses to L-glutamic acid60-L-alanine30-L-tyrosine (GAT).

Immune responses to GAT are controlled by H-2-linked Ir genes; soluble GAT stimulates antibody responses in responder mice (H-2b) but not in nonresponder mice (H-2q). In nonresponder mice, soluble GAT stimulates suppressor T cells that preempt function of helper T cells. After immunization with soluble GAT, spleen cells from (responder x nonresponder: H-2b X H-2q)F1 mice develop antibody responses to responder H-2b GAT-M phi but not to nonresponder H-2q GAT-M phi. This failure of immune F1 spleen cells to respond is due to an active suppressor T cell mechanism that is activated by H-2q, but not H-2b, GAT-M phi and involves two regulatory T cell subsets. Suppressor-inducer T cells are immune radiosensitive Lyt-1 +2-, I-A-, I-J+, Qa-1+ cells. Suppressor-effector T cells can be derived from virgin or immune spleens and are radiosensitive Lyt-1-2+, I-A-, I-J+, Qa-1+ cells. This suppressor mechanism can suppress responses of virgin or immune F1 helper T cells and B cells. Helper T cells specific for H-2b GAT-M phi are easily detected in F1 mice after immunization with soluble GAT; helper T cells specific for H-2q GAT-M phi are demonstrated after elimination of the suppressor-inducer and -effector cells. These helper T cells are radioresistant Lyt-1+2-, I-A+, I-J-, Qa-1- cells. These data indicate that the Ir gene defect in responses to GAT is not due to a failure of nonresponder M phi to present GAT and most likely is not due to a defective T cell repertoire, because the relevant helper T cells are primed in F1 mice by soluble GAT and can be demonstrated when suppressor cells are removed. These data are discussed in the context of mechanisms for expression of Ir gene function in responses to GAT, especially the balance between stimulation of helper vs suppressor T cells.

Animals↗
PubMed1983

Induction of monocytic differentiation and bone resorption by 1,25-dihydroxyvitamin D3.

1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] stimulates bone resorption in man and other vertebrates, in part, by increasing the number of osteoclasts, the principal resorbing cells of bone. Because osteoclasts are very likely derived from a member(s) of the mononuclear phagocyte family, we determined if 1,25(OH)2D3 promotes maturation of these cells by studying its effects on the human promyelocytic leukemia cell line HL-60. Of the vitamin D3 metabolites tested, only 1,25(OH)2D3, at 10(-10) to 10(-7) M, induces the differentiation of HL60 into mono- and multinucleated macrophage-like cells. Phenotypic change is evident within 24 hr and reaches a plateau between 72 and 96 hr of incubation. The changes are metabolite-specific and include (i) adherence to substrate, (ii) acquisition of the morphological features of mature monocytes, (iii) a 4- to 6-fold enhancement in lysozyme synthesis and secretion, (iv) increase in the fraction of alpha-naphthyl acetate esterase-positive cells from approximately 2% to 100% of the population, and (v) the acquisition of several monocyte-associated cell surface antigens. More importantly, treated HL-60 cells acquire the capacity to bind and degrade bone matrix, two of the essential, functional characteristics of osteoclasts and related bone-resorbing cells. These results, considered together with the reported action of 1,25(OH)2D3 on nontransformed mononuclear cells, are consistent with the view that vitamin D3 enhances bone resorption and osteoclastogenesis in vivo by promoting the differentiation of precursor cells.

Animals↗
PubMed1983

Expression of cell surface antigens by suppressor T cell hybridomas. I. Comparison of phenotype and function.

The phenotypic expression of cell surface markers by T cell hybridomas that elaborate suppressor factors specific for the polymers L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT) or L-glutamic acid50-L-tyrosine50 (GT) has been analyzed. We found that determinants encoded by the I-J subregion of the H-2 complex were borne on the surface of these hybrid cells and on the factors they secrete, whereas I-J determinants were not expressed by the AKR thymoma fusion parent, BW5147. The level of expression of I-J determinants fluctuated widely depending upon culture conditions, but I-J products and other cell surface markers of normal T cells could be quantitatively increased, or induced to appear, by treatment of the hybridomas with chemical agents, such as dimethyl sulfoxide (DMSO) or phorbol myristate acetate (PMA). In contrast, the surface expression of the viral product gp70 was decreased by the same treatment. Using chemical induction, we typed BW5147, a group of antigen-specific suppressor T cell hybridomas, and two control hybridomas for expression of I-J, Thy-1, Lyt, and H-2K alloantigens. Also, a haplotype-specific hybridoma that produces an antigen-nonspecific factor was analyzed. The results demonstrated that BW5147 failed to express I-J or Lyt alloantigens but expressed Thy-1.1 and H-2Kk gene products. The pattern of expression of these antigens by T cell hybridomas was very complex, but three conclusions could be drawn: 1) Good correlation exists between the expression of certain I-J determinants and the ability of T cell hybridomas to produce suppressor factor. 2) The expression of Thy-1, Lyt, or H-2Kk determinants is variable, and no correlation was found between expression of these antigens and the ability to produce active suppressor factors. 3) I-Jk products contributed by the AKR thymoma fusion partner are expressed by T cell hybridomas.

Absorption↗
PubMed1982

The Qa2 subregion controls the expression of two antigens recognized by H-2-unrestricted cytotoxic T cells.

B6.KI mice were immunized with spleen cells from B6.K2, a Qa2-subregion congenic strain. Cytotoxic T cells were generated that recognize two target antigens controlled by this region. One of the target antigens is Qa-2. This was demonstrated by the findings that pretreatment of target cells with monoclonal anti-Qa-2 antibody blocked lysis of target cells, and Qa-2 target antigens and serological determinants had a concordant distribution on a panel of B10.W (wild) mice. The gene controlling the Qa-2 target antigen is not polymorphic because B6.K2 and three strains of Qa-2(+) B10.W mice express the same antigens, as determined by a CTL cold target competition assay. Anti-Qa-2 CTL were H-2 unrestricted because effector cells lysed Qa-2(+) targets irrespective of their H-2 haplotype, including five B 10.W strains, and lysis was not inhibited by pretreating target cells with anti-H-2 sera. The Qa2 subregion does not act as a restricting locus for anti-minor-H antigen CTL. A second target antigen was detected that was associated with the expression of the Qa-5 determinant. However, CTL activity could not be blocked by pretreating target cells with monoclonal anti-Qa-5. Therefore, the CTL target antigen may be expressed on a Qa-5(-) molecule. Although the Qa-5 associated CTL specificity is only detected on H-2D(b) strains, it is unlikely that CTL recognition is H-2 restricted because anti-H-2(b) sera has no effect in blocking this reactivity. Qa-2 and H-2 class I antigens share a similar structure and serve as target antigens for unrestricted CTL. However, unlike class I H-2 genes, Qa-2 neither restricts antigen-specific CTL nor is polymorphie. Therefore, it is likely that Qa-2 and H-2 are derived from a common ancestral gene and have evolved to serve different functions.

Animals↗
PubMedDate not supplied

Regulation of myc gene expression in HL-60 leukaemia cells by a vitamin D metabolite.

HL-60, a cell line established from a patient with promyelocytic leukaemia, responds to a variety of inducing agents by ceasing division and acquiring some of the characteristics of either granulocytes or monocytes. Among the agents so far tested, only a comparative few occur naturally in vertebrates and would appear to have significant clinical potential in the treatment of leukaemic patients. One of the most promising of these is the dihydroxymetabolite of vitamin D3, 1,25(OH)2D3. This compound circulates in normal man and has a major role in calcium homeostasis. Moreover, it has recently been reported that 1,25(OH)2D3 increases the survival time of mice injected with myeloid leukaemia cells. We and McCarthy et al. have previously shown that HL-60 cells respond to near physiological levels of 1,25(OH)2D3 by rapidly acquiring a number of monocyte-like features. Here we document that these phenotypic changes are preceded by a marked decrement in the expression of the c-myc oncogene. In fact, the diminution in the level of c-myc mRNA parallels the dose dependency and metabolite specificity shown by the various other indicators of phenotypic change. In addition, we demonstrate that removal of vitamin D3, after the onset of maturational change, results in the reappearance of elevated myc mRNA levels. We believe this to be the first demonstration of a sequential relationship between the application of an exogenous inducing agent, a reduction in myc mRNA levels and the development of characteristics associated with normal cell maturation.

Animals↗
PubMedDate not supplied

Adoptive transfer of early and late delayed-type hypersensitivity reactions mediated by human T cells.

Human T cells activated by antigen in vitro mediated both the 2-hour and 24-hour phases of delayed-type hypersensitivity (DTH) when transferred into the mouse footpad. The passively transferred human DTH was similar to murine DTH by kinetics, vasoactive amine dependence, and histologic criteria. These results offer a functional assay for determining whether human T cells are activated by viral or tumor antigens.

Animals↗