Search PubMed⌕ Search

Biomedical subjects

J H Russell

Publications and source records attributed to J H Russell.

At least 73 records · Page 4Linked to original sources
PubMed1986

T cell receptor genes in an alloreactive CTL clone: implications for rearrangement and germline diversity of variable gene segments.

Both cDNA and genomic clones of the T cell receptor (TCR) alpha- and beta-chain genes of the alloreactive cytotoxic T lymphocyte (CTL) clone F3 were examined. Two distinct rearrangement events, one functional and one non-functional, were found for both the alpha and beta loci. Thus only a single functional TCR alpha beta heterodimer could be defined, consistent with allelic exclusion in the TCR genes. The V alpha gene employed by F3 is part of a six-member V alpha subfamily. Genomic clones containing each member of this subfamily were isolated and the V alpha nucleotide sequences determined. Five of these six genes are functional; these genes differ from each other by 7-14% at the amino acid level. A single dominant hypervariable region was defined within this subfamily, in contrast to the pattern of variability seen between V alpha genes in general.

Alleles↗
PubMed1986

Expression of antigen interaction structures on resting and activated cytotoxic lymphocytes.

The expression of T-cell receptor protein and Lyt-2 was examined on resting and activated antigen-specific cytotoxic lymphocytes. Receptor expression was largely independent of the activation state of the cells. In contrast Lyt-2 expression was approximately threefold higher on activated than on resting cells. Since lytic activity varied by as much as 100-fold, it appears that lytic activity is primarily regulated by processes independent of quantitative changes in antigen interaction structures.

Animals↗
PubMed1986

Phorbol-ester stimulated lysis of weak and nonspecific target cells by cytotoxic T lymphocytes.

We have investigated the effects of short-term incubation of cloned and in vivo-produced cytotoxic T lymphocytes (CTL) with phorbol esters on their lytic activity against weak and nonspecific targets. These experiments demonstrate that 4 beta-phorbol-12-myristate, 13-acetate (PMA), 4 beta-phorbol-12,13-dibutyrate, and 4 beta-phorbol-12,13-didecanoate, but not the 4 alpha-phorbol-12,13 didecanoate esters stimulate the lytic apparatus. The stimulation is specific for the CTL rather than the target and appears to be nearly instantaneous in action. This rapid stimulation of the CTL lytic process is consistent with previously reported effects of phorbol esters associated with T cell activation in other functional assays.

Animals↗
PubMed1985

Protection from guanethidine-induced neuronal destruction by nerve growth factor: effect of NGF on immune function.

The chronic administration of guanethidine causes an immune-mediated destruction of sympathetic neurons in rats. Destruction can be prevented by various immunosuppressive agents, including gamma-irradiation and cyclophosphamide, as well as by administration with nerve growth factor (NGF). Experiments were conducted to determine whether: (1) NGF prevented accumulation of guanethidine within sympathetic neurons; and (2) NGF caused an inhibition of immune function by either blocking proliferation of immune-competent cells or by blocking effector function even in the presence of antigen and activated immune cells. NGF did not prevent accumulation of guanethidine within sympathetic ganglia in vivo, a necessary prerequisite for neuronal destruction, nor was it inhibitory on immune function using several assay systems. NGF, purified by either conventional methods or additionally by HPLC ("ultrapure'), did not inhibit either proliferation of cloned cytotoxic T lymphocytes (CTL) to antigen (class I major histocompatibility antigens) or lysis of target cells bearing the appropriate antigens. In addition, NGF did not exhibit growth stimulating effects in this assay system (i.e. it could not substitute for T cell growth factor). NGF also did not cause an inhibition of either murine or rat allogeneic mixed lymphocyte responses measured by lysis of appropriate target cells or proliferation, respectively. Finally, NGF did not inhibit, but rather appeared to stimulate the antibody response to sheep red blood cells generated in vivo in young rats. Thus NGF does not appear to prevent the immune-mediated neural destruction induced by guanethidine by acting as an immunosuppressive agent, but rather acts by some other mechanism such as preventing expression or recognition of antigen(s) on the sympathetic neuron.

Animals↗
PubMed1985

Characterization of an arachidonic acid-selective acyl-CoA synthetase from murine T lymphocytes.

Evidence is presented that the murine thymoma EL4 and cytotoxic T lymphocyte clones possess two distinct long-chain fatty acyl-CoA synthetase activities. One enzyme shows activity toward a broad spectrum of fatty acid substrates, similar to the long-chain fatty acyl-CoA synthetase from rat liver. The other enzyme is selective for arachidonic acid and related fatty acids. Fatty acid competition studies using EL4 microsomes demonstrate that [14C]palmitoyl-CoA synthesis (Km = 13 +/- 1 microM, Vmax = 7 +/- 1 nmol/mg per min) is inhibited by unlabeled palmitate, oleate, linoleate or linolenate (Ki = 15-25 microM) and weakly by arachidonate (Ki greater than 100 microM). Similar inhibition is observed for the activation of [14C]oleate (Km = 31 +/- 3 microM, Vmax = 6 +/- 2 nmol/mg per min). On the other hand, [14C]arachidonyl-CoA synthetase (Km = 15 +/- 3 microM, Vmax = 13 +/- 2 nmol/mg per min) is inhibited by unlabeled arachidonic acid (Ki = 20 microM) but not by unlabeled palmitate, oleate, linoleate and linolenate. The description of arachidonoyl-CoA synthetase in cytotoxic T lymphocyte clones represents the first example of a cell with little or no capacity to synthesize arachidonic acid metabolites, yet which possesses a selective esterification mechanism for the fatty acid. Studies on the specificity of the arachidonic acid-selective acyl-CoA synthetase utilized arachidonic acid metabolites and structurally related fatty acids and yielded two points of interest: (1) metabolism of arachidonic acid to monohydroxy fatty acids (HETEs) resulted in compounds with significantly decreased ability to be activated by the arachidonate-selective acyl-CoA synthetase; (2) arachidonate was a much better substrate than was 5,8,11-eicosatrienoic acid (Km = 41 microM), the fatty acid which accumulates during essential fatty acid deficiency. The possible role of an arachidonic acid-selective acyl-CoA synthetase in lymphocyte activation and as a homeostatic mechanism during essential fatty acid deficiency is discussed.

Adenosine Triphosphate↗
PubMed1985

A single affinity column step method for the purification of ricin toxin from castor beans (Ricinus communis).

A rapid method for purifying ricin toxin from castor beans is presented which uses a single affinity column step to obtain pure toxin from a crude extract of castor beans. A galactosyl-Sepharose affinity matrix was used to bind ricin toxin and its associated agglutinin, which both bind specifically to galactose, from a crude extract. The selective elution of ricin toxin and agglutinin was then achieved by eluting the affinity column with a galactose gradient, which sequentially elutes the two proteins due to a difference in binding avidity to the matrix.

Ricinus communis↗
PubMed1985

Incorporation of 5,8,11,14-eicosatetraynoic acid (ETYA) into cell lipids: competition with arachidonic acid for esterification.

5,8,11,14-eicosatetraynoic acid (ETYA), a widely used inhibitor of cyclooxygenase and lipoxygenase, inhibited the incorporation of 14C-arachidonic acid into cell lipids of the murine thymoma EL4 whereas oleic acid had no effect. Inhibition appeared to result from the ability of ETYA to compete with arachidonic acid for esterification enzymes and to be itself incorporated into cell lipids. The positional specificity for ETYA incorporation was similar to that of arachidonic acid. ETYA, but not oleic acid competed with arachidonate for activation by a selective arachidonoyl CoA synthetase in lymphocytes. This may explain in part the apparent specificity of effects seen on incorporation into whole cells. In addition ETYA, unlike other arachidonate analogs tested previously, caused significant inhibition of the nonselective acyl CoA synthetase in lymphocytes. These results are discussed with respect to the use of ETYA to examine the role of intrinsic arachidonic acid metabolism in cellular processes.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1985

Basic principles of superfund litigation.

Many legal aspects of the 1980 Comprehensive Environmental Response, Compensation, and Liability Act, known as CERCLA, pose problems for industry and the general public. The legal issues are developing and many of the numerous problems will require future resolution in the courts. A plea is made for a cooperative effort by lawyers, regulators, and courts to analyze and solve these problems from a proper perspective.

Environmental Pollution↗
PubMed1985

Interleukin 2-mediated induction of lytic activity in a cloned murine CTL line.

We have analyzed the ability of interleukin 2 (IL 2) to induce lytic activity within a cloned murine H-2Dd-specific CTL line. Weakly lytic CTL harvested 6 to 7 days after previous stimulation with irradiated DBA/2J spleen cells and conditioned medium from secondary MLC (MLC SN) could be reactivated to high antigen-specific lytic activity with highly purified gibbon IL 2 or E. coli-produced human recombinant DNA IL 2. Dose-response curves with IL 2 and MLC SN suggest that IL 2 may be the principal detectable activity in MLC SN that is active on these CTL. Doses of IL 2 or MLC SN that were saturating for the induction of lytic activity were suboptimal for the expression of DNA synthesis measured by 3HTdR incorporation. This is consistent with a mechanism in which different threshold IL 2 concentrations are required to induce these two biologic responses. Finally, we show that IFN-gamma has little effect on the expression of lytic activity either alone or in combination with IL 2 in this bioassay.

Absorption↗
PubMed1985

Inhibition of cytotoxic T lymphocyte-mediated lysis by ETYA: effect independent of arachidonic acid metabolism.

Cytotoxic T lymphocyte (CTL)-mediated lysis of target cells was inhibited by 5,8,11,14-eicosatetraynoic acid (ETYA) and other inhibitors of the lipoxygenase pathway at concentrations that inhibited arachidonic acid metabolism in mixed lymphocyte cultures. Inhibition was reversible and selective for the "lethal hit" stage in the CTL-target interaction. Studies to define CTL-specific arachidonic acid metabolites demonstrated that cloned CTL populations have little or no capacity to metabolize arachidonic acid. Therefore, inhibitor actions appear to be independent of the effects on CTL arachidonic acid metabolism. Alternative explanations for inhibitory effects are discussed.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1985

Analysis of the binding and postbinding activities of an inducible cloned CTL line at the population and the single-cell level.

We have analyzed the binding and lytic properties of a cloned CTL line before and after induction with MLC SN. Functional, specific binding by both effector populations could be demonstrated to occur at 20 degrees C; however, lysis required temperatures greater than or equal to 30 degrees C. Approximately 50% of noninduced cells and 70% of induced cells formed specific conjugates with P815 target cells. Conjugate formation approached maximum levels by 30 min at 20 degrees C for both populations. When low cell concentrations were employed for conjugate formation, the difference between SN-induced cells and noninduced cells was more pronounced. Analysis of the postbinding abilities of these populations at the single-cell level revealed that SN-induced cells were considerably more efficient in lysing attached target cells than were noninduced cells; however, significant lysis by the latter could be demonstrated after long periods. When populations which had intermediate cytolytic activity were compared to optimally induced or noninduced cells, apparent dissociation of the binding and postbinding capacities was observed. Cells harvested 4 days after stimulation with allogeneic cells plus SN displayed maximal binding but low postbinding activities. These results are consistent with the possibility that multiple components of the lytic mechanism are affected following induction and that these components may be asynchronously modulated.

Animals↗
PubMed1984

Phorbol esters inactivate the lytic apparatus of cytotoxic T lymphocytes.

Treatment of cloned murine CTL with phorbol myristate acetate (PMA) initiates the loss of lytic potential of these cells. The process is relatively rapid (t 1/2 = 2.2 +/- 0.7 hr), occurs independently of protein synthesis, and can be largely reversed within 3 hr by incubation in normal medium with or without the addition of supernatants from activated lymphocytes. Examination of PMA-treated or untreated CTL in assays that separate binding and post-binding events suggests that the lytic apparatus itself is a major target of the PMA-initiated event.

Animals↗
PubMed1983

Isolation of alloreactive CTL clones with cyclical changes in lytic activity.

We have isolated two H-2Dd specific CTL clones from CBA anti-DBA/2 MLC that undergo changes in lytic activity against tumor and Con A blast target cells as a consequence of weekly stimulation with irradiated allogeneic cells and conditioned medium from secondary MLC. Lytic activity is highest on days 2 to 3 after stimulation, and lowest on days 5 to 7. CTL that had been irradiated on day 0 before stimulation have significantly greater activity on day 2. Conditioned media alone, in the absence of added allogeneic stimulator cells is capable of supporting, in a dose-dependent fashion, the increase in activity. Collectively, these changes are similar to those described for the induction of lytic activity in nonlytic CTL populations from long-term MLC, and suggest that these cloned lines may be useful to study the modulation of lytic activity of CTL in culture.

Animals↗
PubMed1983

Characterization of a "heteroclitic" cytotoxic lymphocyte clone: heterogeneity of receptors or signals?

In this work we report the isolation of a cloned CTL that recognizes three genetically distinct specificities. Of interest is the fact that the hierarchy of the strength of these specificities is dependent on the functional assay used for their detection. This suggests that either the specificities are the result of interactions with independent receptors or the cell can modulate signals from cross-reactive antigens into different functional responses.

Animals↗
PubMed1983

Accelerated 86Rb+ (K+) release from the cytotoxic T lymphocyte is a physiologic event associated with delivery of the lethal hit.

Cloned CTL have been loaded with the K+ analogue 86Rb+. When mixed with unlabeled target cells, accelerated 86Rb+ release occurs from the CTL. The magnitude of accelerated 86Rb+ release is proportional to the efficacy of the target in standard 51Cr release assays. The signal responsible for accelerated 86Rb+ release has been localized to a postbinding event and has the physiologic requirements of delivery of the lethal hit. Thus, accelerated 86Rb+ release from the CTL represents the first direct observation of a physiologic event within the CTL related to a functional CTL-target interaction.

Animals↗