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T J Rogers

Publications and source records attributed to T J Rogers.

At least 37 records · Page 2Linked to original sources
PubMed1999

Role of interleukin-2 in superantigen-induced T-cell anergy.

T-cell anergy is a state of immunological tolerance characterized by unresponsiveness to antigenic stimulation. Previous studies have shown that anergy is induced in T cells following stimulation in the absence of adequate costimulatory signals. These cells fail to respond to stimulation via the T-cell receptor (TCR), and fail to produce normal levels of interleukin-2 (IL-2). We present results here which show that low concentrations of the superantigen staphylococcal enterotoxin A (SEA) in the absence of antigen-presenting cells induced both proliferation and anergy in the A.E7 T-cell clone. Furthermore, under these conditions, the A.E7 clone remained responsive to exogenous IL-2. Fluorescence-activated cellular cytometry analysis revealed unaltered expression of the TCR/CD3 complex in the anergized clone; however, both CD4 and CD25 expression increased after 24 hr of stimulation by SEA under these conditions. Interestingly, a low level of IL-2 production was measured during the induction of anergy. Most strikingly, stimulation of the A.E7 clone by SEA in combination with exogenous IL-2 resulted in a more pronounced state of anergy. These results suggest that the induction of anergy is a process that is essentially independent of the production of IL-2.

Animals↗
PubMed1998

Characterization of kappa-opioid receptor transcripts expressed by T cells and macrophages.

We have found that the immature T cell lines R1.1 and DPK and the macrophage lines P388D1 and WEHI-3 also express kappa-opioid receptor (KOR) mRNA. Characterization of the KOR transcripts in both brain tissue and these T cells has revealed both the normal full-length as well as a truncated form of the mRNA. Our results show that the truncated transcript lacks the second exon. Primary macrophages express this truncated form of the transcript in the absence of detectable levels of the full-length form. These results suggest a degree of heterogeneity in the expression of the opioid receptors which has not previously been reported.

Animals↗
PubMed1998

Molecular characterization of the putative T-cell receptor cavity of the superantigen staphylococcal enterotoxin B.

A number of investigators have utilized a variety of methods to identify the structural basis for the interaction of superantigens with the T-cell receptor beta-chain. The previous studies strongly suggest that a region of the toxin near residues N23, Y61, Y91 and D209 is important for this binding activity. Examination of crystal structure data shows that these residues line the rim of one side of a shallow cavity in the toxin. In an attempt further to define the face of the staphylococcal enterotoxin B (SEB) molecule involved in the interaction with the beta-chain, we have employed a polymerase chain reaction (PCR)-based, site-specific mutagenesis method to generate amino acid substitutions of residues on the opposite side of this putative T-cell receptor interaction cavity. Our results show that Y175 and N179 appear to be involved in the function of this superantigen, since each of several substitutions at this position exhibits a significantly reduced ability to induce T-cell proliferation. At the same time, mutation of the proximal Y186 does not alter the superantigen activity of SEB. Binding analysis of these mutants shows that class II binding activity is not significantly altered. Analysis of the responding T cells shows that the mutant toxins maintain T-cell receptor V beta selectivity. However, responses of T cells bearing the V beta 8.1 allele appear to be particularly diminished. When viewed in the context of other results reported in the literature, our results suggest that the T-cell receptor interaction site involves SEB residues which ring both the Y175/N179-side and the N23-side of a cavity on one side of the toxin molecule.

Alleles↗
PubMed1997

Structural basis for the interaction of superantigen with the alternative superantigen-binding receptor p85.

Superantigens are microbial products which bind both to the TCR beta-chain and, with moderate affinity, to MHC class II molecules. Class II-bearing cells bind the superantigen and present the superantigen to T cells expressing certain TCR beta-chain variable region alleles. We have previously reported that the superantigen staphylococcal enterotoxin B (SEB) binds with moderate affinity to the protein p85 expressed on COS-1, an African Green Monkey kidney fibroblast-like cell line. In the present report we carry out a structural analysis to examine the basis for the interaction of superantigen to p85. We show that SEC1, SEC2, and SEC3 also bind to p85 based on inhibition of the binding of radiolabeled SEB. On the other hand, SEA, SED, SEE and toxic shock syndrome toxin-1 do not exhibit detectable binding. In an effort to characterize the structural basis for the SEB binding to p85, we have generated both amino- and carboxy-terminal truncations of SEB expressed as fusion proteins with the maltose-binding protein of Escherichia coli. Our results show that the full-length SEB fusion protein and a truncation missing the 81 amino-terminal amino acids both compete successfully with native SEB for binding. On the other hand, carboxy-terminal truncations in which 19 or 34 residues are deleted both fail to compete for binding. These results are consistent with results which show that monoclonal anti-SEB antibodies specific for carboxy-terminal determinants block SEB binding to p85, but an amino-terminal mAb fails to exhibit any alteration in binding. These results suggest that residues at or near the carboxy-terminus of SEB play a role in binding to p85.

Amino Acid Sequence↗
PubMed1997

Inhibition of T cell superantigen responses following treatment with the kappa-opioid agonist U50,488H.

Previous work in our laboratory has shown that cytokine production by primary murine macrophages, and macrophage cell lines, is inhibited following treatment with the kappa-opioid agonist U50,488H. Furthermore, we have found that the participation of both accessory cells and T cells in an antibody response is suppressed by this compound. We have utilized the superantigen staphylococcal enterotoxin B (SEB) to further examine the effects of U50,488H on accessory and T cell function. The results showed that the proliferative response of lymph node T cells to SEB presented by activated macrophages was significantly inhibited by the kappa-opioid agonist at concentrations as low as 100 nM. However, suppression of the T cell response to SEB presented by resting macrophages required 100 times the concentration of U50,488H. On the other hand, the production of IL-2 in response to lymph node T cell stimulation with SEB was not altered by the opioid treatment. Additional experiments utilizing the opiate antagonist naloxone and the kappa-selective antagonist nor-binaltorphimine (norBNI) were performed in order to further characterize the opioid receptor involved in the suppressive activity of U50,488H. Results showed that both naloxone and norBNI were able to block the inhibitory activity of U50,488H. Further analysis showed that the proliferative response of thymic T cells was more sensitive to the effects of U50,488H, and the response with both activated and resting macrophages was suppressed. In addition, the production of IL-2 by the thymic T cells was also inhibited by the opioid treatment. The mechanism of suppression of superantigen-induced T cell responses is discussed.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1997

Morphine alters macrophage and lymphocyte populations in the spleen and peritoneal cavity.

We have previously shown that subcutaneous implantation of a 75 mg morphine pellet results in suppression of the ability of murine splenocytes to mount an antibody response to sheep red blood cells, due in part to a reduction of macrophage function. The present studies used flow cytometry to examine whether the decrement in macrophage function in the spleens of morphine-treated mice results from a reduction in macrophage numbers. Parallel analysis was carried out on non-elicited peritoneal cells. In the spleen, morphine resulted in a reduction in the relative proportion of macrophages and B-cells, with a concomitant increase in the proportion of T-cells. Alteration in the ratio of CD4+ to CD8+ T-cells was not observed. In contrast, in the peritoneal cavity, morphine increased the number of macrophages and reduced the number of B-cells. Naltrexone blocked all of the changes in cellular composition. These results support the conclusion that an important mechanism in the immunosuppression seen in the spleens of mice implanted with morphine pellets is a differential reduction in the number of macrophages and B-cells as compared with T-cells. Further, these studies show that subsets of cells of the immune system are differentially affected by morphine in different anatomical compartments.

Administration, Cutaneous↗
PubMed1997

Mutations affecting the superantigen activity of staphylococcal enterotoxin B.

As a superantigen, staphylococcal enterotoxin B (SEB) possesses the ability to bind to major histocompatibility complex class II molecules and be recognized by T cells bearing certain T-cell receptor (TCR) V beta alleles. Other investigators have utilized site-specific mutagenesis to generate amino acid substitutions to identify residues that may be involved in the interaction with the TCR beta-chain. In an attempt further to define the face of the SEB molecule involved in the interaction with the beta-chain, we have employed a polymerase chain reaction (PCR)-based, site-specific mutagenesis method to generate amino acid substitutions with altered superantigen activity. Our results show that valine at position 169 appears to be involved in the function of this superantigen, since each of several substitutions at this position exhibit a significantly reduced ability to induce T-cell proliferation. Analysis of the responding T cells to the residue 169 substitution shows that the mutant toxins maintain TCR V beta selectivity. At the same time, mutation of the proximal histidine at position 166 does not alter the superantigen activity of SEB. Radiolabelled binding analysis of these H166 and V169 mutants shows that class II-binding activity is not significantly altered. When viewed in the context of other results reported in the literature, combined with the crystal structure of the toxin, our results suggest that the interaction with the TCR probably involves SEB residues which ring a cavity along one side of the toxin molecule.

Animals↗
PubMed1997

Morphine induces sepsis in mice.

Gram-negative sepsis and subsequent endotoxic shock remain major health problems in the United States. The present study examined the role of morphine in inducing sepsis. Mice administered morphine by the subcutaneous implantation of a slow-release pellet developed colonization of the liver, spleen, and peritoneal cavity with gram-negative and other enteric bacteria. In addition, the mice became hypersusceptible to sublethal endotoxin challenge. The effects were blocked by the simultaneous implantation of a pellet containing the opioid antagonist naltrexone. These findings show that morphine pellet implantation in mice results in the escape of gram-negative organisms from the gastrointestinal tract, leading to the hypothesis that morphine used postoperatively or chronically for analgesia may serve as a cofactor in the precipitation of sepsis and shock. In addition, morphine-induced sepsis may provide a physiologically relevant model of gram-negative sepsis and endotoxic shock.

Analgesics, Opioid↗
PubMed1996

In vivo analysis of a superantigen-induced T cell suppressor factor.

We have previously reported that the superantigen staphylococcal enterotoxin B (SEB) was able to suppress an immune response to sheep red blood cells when administered intravenously to mice. While the capacity of the superantigens to stimulate lymphocytes and accessory cell functions has been thoroughly examined, it is clear that these agents may also exhibit potent immunosuppressive activity both in vivo and in vitro. This SEB-induced immunosuppression was determined by our laboratories to be mediated by a population of T suppressor cells. The suppression may be due to the generation of inhibitory lymphokines, including IL-10 or transforming growth factor beta, following superantigen stimulation. Alternatively, the immunomodulatory activity may be due to the activation of antigen-specific and/or genetically restricted suppressor cells by SEB. The mechanism of activity of these suppressor cells has not been fully defined. In this report we wished to determine whether a suppressor factor generated from SEB-activated T cells in vitro may be responsible for the inhibition of antibody or delayed-type hypersensitivity responses in vivo. We observed that both antibody and delayed-type hypersensitivity responses were inhibited following administration of the SEB-induced suppressor factor. The in vivo inhibitory activity of the SEB-induced suppressor factor was found to be genetically restricted at the "I-J" locus. In addition, monoclonal anti-I-J antibodies recognized the suppressor factor in a haplotype-specific fashion. These results show that the suppressive product of SEB-induced T cells possesses the ability to inhibit, in a genetically restricted fashion, both cellular and humoral immune responses.

Animals↗
PubMed1996

Inhibition of primary murine macrophage cytokine production in vitro following treatment with the kappa-opioid agonist U50,488H.

Previous work in our laboratory has shown that both mu- and kappa-opioid agonists exhibit immunosuppressive activity for antibody responses in vitro. Our earlier work has suggested that both accessory cells and T cells may be altered following treatment with the kappa-opioid agonist U50,488H. We intend to further determine the identity of the immune cell population(s) which are affected by opioid treatment, and to determine the nature of the opioid receptor type expressed on these cells. In this study, non- elicited peritoneal macrophages were treated simultaneously with the kappa-agonist U50,488H and lipopolysaccharide (LPS), and the levels of the cytokines interleukin (IL)-1, IL-6 and tumor necrosis factor (TNF)-alpha were determined. The results show that U50,488H had a suppressive effect on the production of TNF-alpha and IL-1 at concentrations as low as 1 nM, while IL-6 was suppressed at concentrations as low as 10 nM. Additional experiments utilizing the opiate antagonist naloxone and the kappa-selective antagonist norbinaltorphimine (norBNI) were performed in order to further characterize the opioid receptor involved in the cytokine suppression produced by treatment with U50,488H. Results showed that naloxone was able to partially block U50,488H suppression while norBNI was able to completely reverse the suppression of IL-6 production. These results suggest that macrophage/monocyte function is significantly modulated following activation of the kappa-opioid receptor.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1996

Production of IL-6 and TNF-alpha by the macrophage-like cell line RAW 264.7 after treatment with a cell wall extract of Candida albicans.

Treatment of the cell wall of Candida albicans with ethylenediamine yields an extract that is antigenic for both the humoral and cell-mediated arms of the immune system. This extract has been shown in previous studies by this laboratory and others to possess potent immunomodulatory activity. We report results here that show that treatment of the macrophage-like cell line RAW 264.7 with the ethylenediamine cell wall (EDA-CW) extract results in an increase in the production of both interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha). Our results also show that the EDA-CW extract possess potent costimulatory activity when combined with interferon-gamma (IFN-gamma). We have found, on the other hand, that EDA-CW extract-treated cells fail to produce elevated levels of IL-1 either alone or in combination with IFN-gamma as a costimulus. Our analysis also shows that the activation of TNF-alpha production by the EDA-CW extract appears to be at the level of transcription, since Northern blot analysis shows that the increase in the level of TNF-alpha mRNA is essentially identical to the rise in TNF-alpha activity released. We suggest that a component of the immunomodulatory activity of the EDA-CW extract is via the activation of macrophage function.

Animals↗
PubMed1996

The relevance of opioids and opioid receptors on immunocompetence and immune homeostasis.

Since the previous review on the role of opioids in the immune system, numerous investigative teams have contributed to the growing pool of information illustrating the tangible relationship between opioids and immune function, particularly as this association pertains to bacterial and viral pathogens. In addition, the recent cloning of both neural- and immune-derived opioid receptors will ultimately facilitate the identification of molecular events that are responsible for the immunomodulatory effects that are mediated by receptor ligation. Specifically, the administration of opioids in vivo can potentially affect the immune system either through direct interaction with receptors on the effector cells or indirectly, through the ligation of receptors found within the central nervous system. This indirect routing is hypothesized to involve secondary pathways including the hypothalamic pituitary adrenal (HPA) axis and the sympathetic nervous system ultimately resulting in immunomodulation. Consequently, a portion of this review addresses the recent data on leukocyte-derived opioid receptors and the potential immunoregulatory role relative to opiold receptors found within the central nervous system. In addition, recent observations on the effects of opioids and immunocompetence is reviewed from both a molecular and cellular perspective. Finally, the consequence of opioid exposure on the competence of the host immune system to microbial pathogens is summarized.

Amino Acid Sequence↗
PubMed1995

Modulation of macrophage phagocytic activity by cell wall components of Candida albicans.

Cell wall components of the pathogenic yeast Candida albicans have been shown to possess significant immunomodulatory activity both in vivo and in vitro. We have previously found that an ethylenediamine (EDA) extract of the Candida cell wall exhibits significant immunosuppressive activity. In an effort to further characterize the immunomodulatory activity of the EDA extract, we attempted to determine the effect of this extract on macrophage phagocytic activity. Our results show that nonelicited peritoneal macrophages treated for 24 or 48 hr with the EDA extract fail to phagocytize Candida yeast cells normally. We have observed that the phagocytosis of Candida is mediated by a combination of lectin-like receptor-, Fc receptor-, and complement receptor-type 3 (CR3)-dependent processes. Results show, however, that the most efficient uptake of this organism is dependent on CR3-mediated phagocytosis. Experiments carried out under various opsonic conditions suggest that the level of CR3-mediated phagocytosis of Candida is depressed following EDA extract treatment. These results show that a substantial mechanism of macrophage phagocytosis is depressed following contact with cell wall components of Candida.

Animals↗
PubMed1995

Detection of kappa-opioid receptor mRNA in immature T cells.

The R1.1 cell line has been shown to express kappa-opioid receptors on the cell surface. Our analysis shows that the R1.1 cell line exhibits a CD4NEG CD8NEG CD3LOW CD25LOW cell surface phenotype, characteristic of thymocytes in one of the early stages of differentiation. We have developed reverse transcriptase polymerase chain reaction (RT-PCR) conditions that permit the detection of mRNA coding for the kappa-receptor. Using cell fractionation techniques we have isolated CD4NEG CD8NEG thymocytes, and analysis by RT-PCR shows that these primary immature thymocytes also express the kappa-opioid receptor. We hypothesize that the expression of kappa-opioid receptor may be a marker which is characteristic of immature T development.

Animals↗