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J A Wolos

Publications and source records attributed to J A Wolos.

At least 19 recordsLinked to original sources
PubMed1995

Effects of an S-adenosyl-L-homocysteine hydrolase inhibitor on murine macrophage activation and function.

The S-adenosyl-L-homocysteine (AdoHcy) hydrolase inhibitor MDL 28,842 has been demonstrated to be a potent inhibitor of T-cell activation, both in vitro and in vivo. Although the inhibition of T cells in vitro was independent of macrophages, the direct effect of MDL 28,842 on macrophages is unknown. In this report the effects of MDL 28,842 on macrophage cytokine production, cell-surface antigen expression, and antigen processing and presentation were examined. Lipopolysaccharide (LPS) stimulation of IL-1 synthesis by peritoneal macrophages was not effected by MDL 28,842 using cells obtained from B10.A and B10.B mice and weakly inhibited using cells from BALB/C mice (IC50 > 10 microM). In contrast, TNF-alpha synthesis by BALB/C macrophages was inhibited by MDL 28,842 with an IC50 < 0.1 microM. B10.A and B10.B macrophages did not produce detectable TNF-alpha in response to LPS in this system. Treatment with 1-10 microM MDL 28,842 resulted in a modest decrease in major histocompatibility complex class II (MHC-II) determinant expression by Interferon-gamma-activated macrophages. The expression of other cell-surface markers was not altered in the presence of MDL 28,842. The processing of antigen and its presentation by MHC class-II-positive macrophages to a T-cell hybridoma was also not affected by incubation with MDL 28,842.)

Adenosine↗
PubMed1994

Induction of T helper cell hyporesponsiveness in an experimental model of autoimmunity by using nonmitogenic anti-CD3 monoclonal antibody.

Autoimmune diseases can be characterized by increases in Th cell activities, suggesting that inhibition of Th cell function might ameliorate autoimmunity. We have recently reported that administration of nonmitogenic anti-CD3 mAb (nmCD3) to nonautoimmune mice can induce long-term Th cell hyporesponsiveness, reflected by reduced IL-2 secretion upon re-exposure to Ag. This study was designed to determine the effects of nmCD3 on autoimmunity by using the murine collagen-induced arthritis model. Treatment of DBA/1 mice with nmCD3 delayed the onset and reduced the severity of arthritis in mice immunized with type II collagen (CII). This effect was not caused by depletion of T cells or modulation of TCR. The observed inhibition of arthritis was not caused by decreased Ab production, as anti-CII titers were not affected. Rather, lymph node cells from CII-immunized mice treated with nmCD3 were hyporesponsive to in vitro stimulation with CII. This hyporesponsiveness was reflected by a marked decrease in secretion of IL-2 and IFN-gamma, but not of IL-4, which suggests that nmCD3 had its principal effect on Th1 cells. The hyporesponsiveness was not Ag-specific, because IL-2 and IFN-gamma production in response to a pan-T cell mitogen was also reduced. These results demonstrate that induction of Th1 cell hyporesponsiveness with nmCD3 can significantly alter the course of CIA and suggest that IL-2 and/or IFN-gamma play a crucial role in disease pathogenesis.

Animals↗
PubMed1993

Immunosuppression mediated by an inhibitor of S-adenosyl-L-homocysteine hydrolase. Prevention and treatment of collagen-induced arthritis.

The potent irreversible inhibitor of S-adenosyl-L-homocysteine hydrolase (Z)-5'-fluoro-4',5'-didehydro-5'-deoxyadenosine (MDL 28,842) was examined for its effect on the development and treatment of collagen-induced arthritis in mice. We have previously shown that MDL 28,842 inhibits T cell activation without affecting B cell activation. Animals were dosed with MDL 28,842 at 5, 2.5, or 1 mg/kg/day p.o. in water beginning 1 day before immunization with chick type II collagen (CII) and continuing through day 51 postimmunization. None of the animals treated with MDL 28,842 at 5 or 2.5 mg/kg/day developed arthritis compared with 87.5% of the controls. Animals treated with 1 mg/kg MDL 28,842 had a delay in the development of the disease and a decreased incidence of arthritis (55%) during the course of treatment. After the treatment was discontinued, 40% of the mice in the 5-mg/kg treatment group, 60% of the mice who had previously received 2.5 mg/kg MDL 28,842, and 27% of the mice in the 1-mg/kg treatment group remained free of any signs of arthritis. Treatment with MDL 28,842 also lowered serum anti-CII IgG levels. In addition, T cells taken from animals immunized with CII and treated with 2.5-mg/kg/day MDL 28,842 had a lower proliferative response to denatured CII in vitro than controls. Therapeutically, MDL 28,842 was administered to animals at 2.5 mg/kg/day p.o., beginning at the first clinical signs of arthritis and continuing for 4 wk. Over the course of treatment, there was significantly less clinical disease in animals given MDL 28,842. In addition, at the end of treatment, hind paws were removed from the animals and examined radiographically and histologically for joint pathology. Animals treated with MDL 28,842 had significantly fewer bone lesions than control animals. These results suggest that inhibitors of S-adenosyl-L-homocysteine hydrolase may be effective anti-arthritic agents.

Adenosine↗
PubMed1993

Selective inhibition of T cell activation by an inhibitor of S-adenosyl-L-homocysteine hydrolase.

Defects in the enzymes involved in the pathway of S-adenosylmethionine (AdoMet) metabolism, or inhibition of those enzymes, results in profound immunodeficiency. We have examined MDL 28,842, a novel irreversible inhibitor of S-adenosyl-L-homocysteine hydrolase (AdoHcyase), an enzyme involved in AdoMet metabolism, to determine its effect on the immune system and to investigate its potential as an immunosuppressive agent. The stimulation of human mononuclear cell proliferation in vitro with Con A, a T cell mitogen, and PWM, a T-dependent B cell mitogen, were inhibited by MDL 28,842. The 50% inhibitory concentration for both were 0.33 microM. In murine spleen cells, MDL 28,842 was a potent, nontoxic, inhibitor of Con A-stimulated T cell proliferation (IC50 = 0.19 microM) but did not affect LPS-induced B cell proliferation. This selective suppression was also observed when enriched murine T and B cells were stimulated with mitogens, although S-adenosyl-L-homocysteine (AdoHcy), the substrate of AdoHcyase, was similarly elevated in both populations. In addition to proliferation in response to a number of stimuli, IL-2 production and the expression of IL-2R by mitogen-stimulated T cells were inhibited by MDL 28,842. These results suggest a direct effect of MDL 28,842 on T cells. In vivo, the antibody response to a T cell-dependent Ag, OVA, was inhibited by MDL 28,842. The response of splenic T cells from these animals to OVA in vitro were similarly depressed compared with controls. The results demonstrate that MDL 28,842 is a potent nontoxic immunosuppressive agent, which has selectivity for T cells and therefore may be useful in the treatment of T cell-mediated disorders, such as autoimmune disease and tissue transplantation.

Adenosine↗
PubMed1993

Immunomodulation by an inhibitor of S-adenosyl-L-homocysteine hydrolase: inhibition of in vitro and in vivo allogeneic responses.

The response of murine T cells to MHC class II determinants on allogeneic cells induces helper T cell activation and the development of cytotoxic T cells. We have recently established that an S-adenosyl-L-homocysteine hydrolase inhibitor, (Z)-5'-fluoro-4',5'-didehydro-5'-deoxyadenosine (MDL 28,842), is a potent immunosuppressive agent which selectively inhibits T cell activation. In this report we characterize the effect of MDL 28,842 on in vitro and in vivo models of transplant rejection. In vitro, MDL 28,842 inhibited the generation of cytotoxic T cells in the murine mixed lymphocyte reaction with an IC50 of less than 0.1 microM. MDL 28,842 (1.0 microM) totally inhibited the generation of cytotoxic T cells when added up to 3 days after the initiation of culture with no apparent cell toxicity. In vivo, MDL 28,842 given by gavage at 5.0, 2.5, or 1.0 mg/kg/day inhibited the increase in popliteal lymph node weight induced by injection of allogeneic spleen cells into the footpad. MDL 28,842 was also evaluated in a model of graft rejection. Skin allografts on animals given MDL 28,842 at 5 mg/kg/day (ip) for the first 6 days following transplantation survived for 12.2 days, compared to 8.7 days for control animals. Cyclosporin A (CSA) given at 5.0 mg/kg/day did not prolong graft survival. The combination of MDL 28,842 and CSA was not any more effective than MDL 28,842 alone. Based on these findings, we suggest that MDL 28,842 is useful in the prevention of allograft rejection.

Adenosine↗
PubMed1990

Methylacetylenic putrescine (MAP), an inhibitor of polyamine biosynthesis, prevents the development of collagen-induced arthritis.

The objective of the present investigation was to examine the effects of an irreversible inhibitor of ornithine decarboxylase (2R,5R)-6-heptyne-2,5,diamine (methylacetylenic putrescine, MAP) on experimentally induced arthritis in mice. MAP (0.5-0.05%) was administered in drinking water to DBA/1 mice immunized with native chick type II collagen (CII). The development of arthritis was inhibited only in those mice receiving 0.5% MAP; lower doses were ineffective. Putrescine and spermidine levels were decreased and spermine levels were increased in spleen and lymph node cells from drug-treated mice compared to control arthritic mice. Furthermore, when control mice were developing arthritis, serum anti-CII antibody levels were lower in the MAP-treated group. MAP inhibited antibody production early in the immune response to CII; there was an association between inhibition of antibody production and inhibition of the development of arthritis. When MAP was discontinued, the nonarthritic, drug-treated mice did not develop the disease. Late administration of MAP (beginning 19 days after CII immunization) did not affect the incidence or the severity of the arthritis. Cyclophosphamide treatment begun at the same time significantly inhibited the development of the disease. In vitro T cell responses to denatured type II collagen (dCII) in untreated and MAP-treated mice were examined 14 days after immunization with CII. This is a time of peak T cell responsiveness in untreated animals. MAP treatment had no effect on the T cell response to dCII. These results indicate that MAP can prevent the development of CII-induced arthritis, possibly by inhibiting the autoantibody response. Therefore, inhibitors of polyamine biosynthesis deserve further investigation as potential immunosuppressive agents.

Alkynes↗
PubMed1988

Inhibition by probucol of interleukin 1 secretion and its implication in atherosclerosis.

Intravenous injection of 1.5 mg of acetylated low-density lipoprotein (LDL) or 100 micrograms of lipopolysaccharide (LPS) to zymosan-primed mice induced a decrease in serum zinc levels measured 6 hours after injection, suggesting the release of interleukin 1 (IL-1). Oral administration of probucol, 100 mg/kg once daily for 14 days, inhibited the LPS-induced fall in serum zinc levels, suggesting inhibition of IL-1 release. Direct evidence for inhibition of IL-1 release by probucol was obtained with an ex vivo system in which, compared with controls, peritoneal macrophages from probucol-treated mice (100 mg/kg orally X 3, or 0.25% in the diet for 3 weeks) secreted 80 to 90% less IL-1 upon LPS stimulation, measured by the C3H/HeJ thymocyte proliferation assay. Inhibition of IL-1 secretion by probucol may contribute to the therapeutic effect of probucol in atherosclerosis since as little as 1 unit of recombinant IL-1 beta was found to induce proliferation of aortic smooth muscle cells. With regard to the endogenous stimulus for IL-1 secretion, oxidized LDL is a putative candidate because it is capable of stimulating peritoneal macrophages to secrete IL-1. Because oxidized LDL is involved in the transformation of macrophages to foam cells, our data on IL-1 induction by oxidized LDL and the mitogenic effect of IL-1 on aortic smooth muscle cells suggest that activated macrophages play an important role in atherogenesis.

Animals↗
PubMed1986

Factors in AMLR culture supernatant which mediate the cytotoxic T-cell response to hapten-altered self: interaction with macrophages.

Supernatants from autologous mixed lymphocyte reaction (AMLR) cultures mediated the cytotoxic T-cell response in a system containing T cells and mitomycin C-treated, TNP-modified syngeneic thymocytes. No cytotoxic activity developed in the absence of the AMLR supernatants. The removal of thymic adherent cells abrogated the effect of the AMLR supernatants in the generation of cytotoxic cells. AMLR helper activity was restored following the addition of small numbers of splenic adherent cells. These results led to speculation that the AMLR supernatant interacted with accessory cells. Examination of the supernatant revealed significant levels of colony stimulating factor (CSF), and interferon-gamma (IFN-gamma). Functionally, incubation of the AMLR supernatant with P388D1, a macrophage tumor line, resulted in the production of interleukin 1 (IL-1). CSF is a major inducer of IL-1 synthesis. In addition, the AMLR supernatant induced the expression of Ia antigens on the P388D1 cells. IFN-gamma has been reported to mediate this activity. Although both lymphokines were present and appeared to have an effect on macrophages, it was unknown if both were required for cytotoxic T-cell development in this system. Samples of AMLR supernatant were incubated for 10 min at various temperatures. The ability of the AMLR supernatants to mediate cytotoxic T-cell activation was sensitive to incubation at 80 or 90 degrees C. Interestingly, at these temperatures CSF activity in the bone marrow colony-forming cell assay was enhanced. In separate experiments, AMLR culture supernatant was dialyzed against a pH 2 buffer. The induction of IA antigens by these supernatants was sensitive to dialysis at this pH. The similarity with IFN-gamma provides further evidence that this activity was mediated by IFN-gamma in the AMLR supernatants. The ability of the AMLR supernatants to mediate the cytotoxic T-cell response to altered self was also pH 2 sensitive. In contrast, IL-1 inducing capability and bone marrow colony growth, both CSF activities, were not reduced by pH 2 dialysis. Taken together, these data demonstrate a primary role for an IFN-like molecule, present in the AMLR supernatant, on cytotoxic T-cell activation. CSF involvement in this response is suggested by its IL-1 inducing activity, but cannot be definitively proven in the present study.

Animals↗
PubMed1985

Suppression of a polyclonal B-cell response by supernatants from the murine autologous mixed lymphocyte reaction.

Previously, we have demonstrated that supernatants from autologous mixed lymphocyte (AMLR) cultures contain helper factors which can mediate the development of a cytotoxic T-cell response to hapten modified self. In the current study, the effect of AMLR supernatants on the humoral response was explored. BALB/C splenic non-T cells produced a large polyclonal antibody response to lipopolysaccharide (LPS), as measured in a Protein A SRBC plaque assay. Surprisingly, syngeneic AMLR supernatants suppressed the LPS-induced generation of plaque-forming cells. The presence of T cells in the stimulated cultures did not affect suppressor activity. The decreased response was not the result of a shift in kinetics, as maximal activity was observed on Day 4, whether or not AMLR supernatants were added. The AMLR culture supernatants were most effective in suppressing the plaque-forming cell response when added at the initiation of culture. AMLR supernatants added after 24 hr of culture resulted in only about 50% of maximum suppression. Supernatants added at 48 or 72 hr had no effect. Interferon-gamma (IFN-gamma) has been detected in AMLR culture supernatant and has been reported to suppress the development of plaque-forming cells in response to LPS. However, it is unlikely the suppressive activity observed in these studies is due to IFN-gamma. Dialysis of the AMLR culture supernatant against a pH 2 buffer for 24 hr or incubation at 70, 80, or 90 degrees C for 10 min, treatments that inactivate IFN-gamma, enhanced suppression. These results suggest that in addition to cytotoxic-T-cell helper factors, the cellular interactions in the AMLR induces the production of a stable mediator(s) which is able to directly suppress B cells at an early stage of their development into plasma cells.

Animals↗
PubMed1985

Helper factors for hapten-self cytotoxic T cells occur in NZB culture supernatants despite deficient AMLR.

The ability of helper T cells from NZB mice to produce non-interleukin 2 (IL-2) lymphokines in the autologous mixed lymphocyte reaction (AMLR) was examined. Factors present in normal AMLR culture have been previously reported to mediate the development of a cytotoxic T-cell response to trinitrophenyl (TNP)-modified syngeneic thymocytes. Young NZB mice, like the normal strains, were able to produce the helper factors in the AMLR and to utilize these mediators in the cytotoxic induction system. Old autoimmune NZB mice demonstrated a poor proliferative response in the AMLR and were unable to activate hapten-specific cytotoxic cells in the presence of AMLR culture supernatant from either young or old mice. This was not due to a lack of cytotoxic precursors, nor was it a normal consequence of aging, but may be related to decreased IL-2 production by helper T cells. Interestingly, supernatant from AMLR proliferation deficient old NZB mice contained normal amounts of the AMLR helper factor. These data suggest that AMLR helper factor production is not directly related to the proliferative response and that two different helper-T-cell subpopulations may be responsible for these activities. The production of these mediators in mice which cannot utilize them raise questions about their role in autoimmunity.

Aging↗
PubMed1984

Helper cells in the autologous mixed lymphocyte reaction (AMLR). IV. H-2 restriction and specificity of cytotoxic cells induced by AMLR helper factor.

Supernatants from Day 3 cultures of T cells stimulated with syngeneic non-T cells in the autologous mixed lymphocyte reaction (AMLR) contained a T-cell factor distinct from interleukin 2 (IL-2). The AMLR factor could mediate the cytotoxic response of T cells to hapten-modified nonstimulatory syngeneic cells. The activity of this helper factor was H-2 unrestricted. However, the cytotoxic cells which developed in the presence of this factor were H-2 restricted and hapten specific.

Animals↗
PubMed1982

Helper cells in the autologous mixed lymphocyte reaction. III. Production of helper factor(s) distinct from interleukin 2.

In normal mice, the autologous mixed lymphocyte reaction (AMLR) can activate helper T cells that, in the presence of hapten-modified syngeneic cells, can induce a hapten-specific cytotoxic response. Supernatants from AMLR cultures contain a factor(s) that will mediate a cytotoxic T cell response to hapten-altered self. The AMLR factor is effective in facilitating the generation of cytotoxicity only in those cultures containing both T cells and hapten-altered, syngeneic, nonstimulatory cells. Factor production requires an interaction between Lyt-1+23- cells and non-T cells (the T cells synthesize it). The AMLR factor does not appear to be interleukin 2 (IL-2) because it does not activate thymocytes in the presence of antigen, nor does it maintain an IL-2-dependent cell line or function in co-stimulator assays. For the AMLR factor to facilitate the generation of cytotoxicity, thymic adherent cells are a necessary intermediate. These data suggest that the factor recoverable from AMLR cultures acts early in the cytotoxic pathway, before IL-1 production.

Animals↗
PubMed1981

B lymphocyte function in B cell chronic lymphocytic leukaemia.

B-enriched lymphocyte populations from patients with chronic lymphocytic leukaemia (CLL) were compared to B-enriched lymphocyte populations from normal age-matched controls for their ability to stimulate a proliferative response and to generate cytotoxic cells in allogeneic mixed lymphocyte cultures (MLC). The proliferative responses of MLCs were less than normal when the stimulating cells originated from B cells of patients with CLL. The degree of stimulation provided by the B cells from the patients with CLL inversely correlated with the peripheral white cell count. Lymphocytes from patients providing a poor stimulatory signal in the MLC tended to have less "Ia-like" antigen than lymphocytes giving a moderate level of stimulation. B lymphocytes from patients with CLL which stimulated poorly in the MLC also failed to generate specific cytotoxic cells even when provided with a normal proliferative trigger. These data suggest that B lymphocytes from cases of CLL with markedly elevated leucocyte counts may have a diminished concentration of both "Ia-like" and serum defined antigens.

B-Lymphocytes↗