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R Dziarski

Publications and source records attributed to R Dziarski.

At least 19 recordsLinked to original sources
PubMed1992

Synergistic enhancement of T cell responses and interleukin-1 receptor expression by interleukin-1 and heparin or dextran sulfate.

Heparin markedly enhances generation of cytotoxic T lymphocytes against allogeneic cells and histocompatible tumors. In this study, we demonstrated a marked synergism between heparin and low concentrations of recombinant IL-1-alpha and IL-1-beta in enhancement of cytotoxic T cell responses in mice. Low molecular weight (8000 Da) dextran sulfate also enhanced the T cell responses and synergized with IL-1, whereas, de-N-sulfated heparin was devoid of both of these activities. The synergistic effect was selective for IL-1, because there was no synergism between heparin or dextran sulfate and other cytokines (tumor necrosis factor-alpha, IL-4, and, as shown previously, IL-2). Heparin did not increase the production of IL-1 (and IL-2, as shown before). Heparin did not bind to IL-1, despite significant amino acid homology between IL-1 and heparin-binding endothelial cell growth factors. Heparin enhanced the growth-promoting effect of IL-1 on the IL-1-dependent helper T cell clone, D10.G4.1, and enhanced IL-1 receptor expression on these cells. These data indicate that heparin acts directly on the T cells and enhances their responsiveness to IL-1 by up-regulating IL-1 receptor expression.

Animals↗
PubMed1991

Demonstration of peptidoglycan-binding sites on lymphocytes and macrophages by photoaffinity cross-linking.

One dominant binding site (70 kDa 6.5 pI protein) for bacterial cell wall peptidoglycan (PGN), a macrophage activator and polyclonal B cell mitogen, was demonstrated on mouse B and T lymphocytes and macrophages by photoaffinity cross-linking and two-dimensional polyacrylamide gel electrophoresis. This binding site was not present on erythrocytes. The binding was specific for polymeric PGN and was competitively inhibited by unlabeled PGN with IC50 = 48 micrograms/ml (0.38 microM). The binding was partially inhibited by O-acetylated PGN monomers (IC50 = 469 micrograms/ml, 521 microM), dextran sulfate (IC50 = 1024 micrograms/ml, 124 microM), and (GlcNAc)3 (IC50 = 6.6 mg/ml, 10 mM), and was not inhibited by non-O-acetylated PGN monomers and dimers, muramyl dipeptide, PGN pentapeptide, GlcNAc, teichoic acid, protein A, and gelatin. The cell surface location of the 70-kDa PGN-binding protein was indicated by the ability of PGN to bind to this protein in intact metabolically inactive cells (at 4 degrees C and in the presence of 0.1% NaN3) and by the ability to extract the 70-kDa PGN-binding protein from viable B lymphocytes by noncytotoxic concentration of n-octyl-beta-D-glucopyranoside.

Affinity Labels↗
PubMed1991

Peptidoglycan and lipopolysaccharide bind to the same binding site on lymphocytes.

Bacterial cell wall peptidoglycan (PGN) and lipopolysaccharide (LPS), which are both macrophage activators and polyclonal B cell mitogens, were shown to bind to the same dominant 70-kDa 6.5 pI protein on the surface of mouse B lymphocytes. This conclusion was supported by the following results: (a) the PGN- and LPS-binding proteins co-migrated following photoaffinity cross-linking and two-dimensional polyacrylamide gel electrophoresis; (b) cross-linking of PGN to this 70-kDa protein was competitively inhibited by LPS (IC50 = 7.3 microM), LPS from a deep rough mutant (IC50 = 6.9 microM), and lipid A (IC50 = 18-72 microM); (c) cross-linking of LPS to this 70-kDa protein was competitively inhibited by polymeric soluble PGN (IC50 = 0.09 microM) and sonicated high Mr PGN (IC50 = 0.6 microM); (d) cross-linking of both PGN and LPS to this 70-kDa protein was also competitively inhibited by dextran sulfate (IC50 = 115-124 microM); (e) cross-linking of both PGN and LPS to this 70-kDa protein was inhibited by a (GlcNAc)2-specific lectin; and (f) peptide maps of the 70-kDa proteins digested with chymotrypsin, subtilisin, staphylococcal protease V, or papain were identical for PGN- and LPS-binding proteins and unique for each enzyme. Based on competitive inhibition experiments, binding of PGN to the 70-kDa protein was 20-1200 times stronger than the binding of LPS or lipid A on a per mol basis. However, when aggregated micellar structures of LPS or lipid A were considered, the avidities of LPS and PGN binding were similar. These results demonstrate binding of PGN and LPS to the same 70-kDa protein on lymphocytes and suggest that the binding is specific for the (GlcNAc-MurNAc)n backbone of PGN and the (GlcNAc)2 part of lipid A.

Affinity Labels↗
PubMed1989

Enhancement of mixed leukocyte reaction and cytotoxic antitumor responses by heparin.

The immunomodulating effects of heparin and natural and synthetic heparinoids (which are now undergoing clinical trials for the treatment of AIDS) on cellular immunity (DNA synthesis and cytotoxic responses of mouse lymphocytes to allogeneic cells and histocompatible tumors) were studied. The results showed that (1) high and low m.w. heparin enhanced mouse antitumor and antiallogeneic cell responses in vitro; (2) other sulfated heparinoids did not have this enhancing activity and some of them (including dextran sulfate) totally suppressed generation of cytotoxic cells; (3) these immunomodulating activities of heparin and heparinoids did not correlate with their anticoagulant effects, degree of sulfation, and mitogenic activity; (4) heparin did not increase the production of IL-2 and did not enhance the action of IL-2 on the cells in MLC, heparin also had no effect on the growth-promoting activity of IL-2 on cloned cytotoxic T cells; (5) heparin had a synergistic enhancing effect with IL-1 on the generation of cytotoxic cells in MLC; and (6) heparin abolished endothelial cell growth factor-induced suppression of cytotoxic response. The latter two effects by themselves, however, could not fully explain the entire immunoenhancing activity of heparin. These results indicate that heparin and heparinoids have multiple effects on the immune system and that some of them can enhance, whereas others can suppress cell-mediated responses.

Adjuvants, Immunologic↗
PubMed1989

Correlation between ribosylation of pertussis toxin substrates and inhibition of peptidoglycan-, muramyl dipeptide- and lipopolysaccharide-induced mitogenic stimulation in B lymphocytes.

Selective inhibition by pertussis toxin (PT) of mitogenic activation of mouse B lymphocytes by bacterial mitogens (peptidoglycan and lipopolysaccharide) and muramyl dipeptide (a synthetic analog of peptidoglycan fragment) was demonstrated. Mitogenic activation of B cells by protein kinase C activators and ionomycin was insensitive to PT. Also PT did not inhibit peptidoglycan- and lipopolysaccharide-induced differentiation of B cells into Ig-secreting cells, when it was added to the cultures after the proliferative stage of the response. B lymphocyte membranes contained two major PT substrates (40 and 41 kDa). The extent of PT-mediated ADP ribosylation of these substrates correlated with the degree of PT-mediated inhibition of mitogenic stimulation of B cells. B cell stimulation by all mitogens tested was not inhibited by cholera toxin at nontoxic concentrations that are known to cause maximal increase in cAMP in B cells. Since the only known substrates for PT-mediated ADP ribosylation in mammalian cells are the alpha subunits of some G proteins, our data suggest that G proteins are present in B cell membranes and that they are involved in B cell activation induced by bacterial mitogens.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1988

Enhancement of B-cell stimulation by muramyl dipeptide through a mechanism not involving interleukin 1 or increased Ca2+ mobilization or protein kinase C activation.

Muramyl dipeptide (MDP) enhanced mitogenic stimulation of mouse lymphocytes by polyclonal B cell activators (peptidoglycan, lipopolysaccharide, Staphylococcus aureus Cowan I cells, and pokeweed mitogen), but not by T-cell mitogens (phytohemagglutinin and concanavalin A). Only adjuvant-active MDP analogs were effective, whereas adjuvant-inactive MDP analogs, muramic acid, peptidoglycan pentapeptide, and low Mr digests of peptidoglycan were not. The half-maximal enhancement was seen at 5-10 microM MDP and occurred at both optimal and suboptimal concentrations of B cell mitogens. The enhancing effect of MDP was exerted on the B cells, since it was T cell- and macrophage-independent and was not mediated by IL-1. MDP was effective during the first 12 hrs of culture, and most strongly enhanced the mitogen-induced DNA synthesis, although significant enhancement of RNA synthesis and B cell differentiation into antibody-secreting cells was also observed. The enhancement of mitogenic response was not due to changed requirements for extracellular or intracellular Ca2+ or to increased activation of protein kinase C. These results demonstrate a novel immunoenhancing effect of MDP that should be useful in the studies on the mechanism of B cell activation.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1987

Binding sites for peptidoglycan on mouse lymphocytes.

Binding of peptidoglycan (PG), a B-cell mitogen and polyclonal activator, to mouse lymphocytes was studied using rosetting with PG-sensitized erythrocytes and a direct binding assay with 125I-labeled PG. Thirty-four percent of splenic lymphocytes formed PG rosettes, 62% of which were inhibited by preincubation of lymphocytes with free PG. Less than 1 or 3% of spleen cells formed rosettes with uncoated or albumin-coated red cells. The formation of rosettes was not inhibited by 0.1% azide and was not dependent on the presence of complement or immunoglobulins. The 125I-PG bound both specifically and nonspecifically to the lymphocytes. The binding was completed within 15-20 min, was proportional to the cell concentration, and was not inhibited by 0.1% azide or treatment of lymphocytes with formalin. The cells had one set of specific binding sites of low affinity (KD = 1.2-4.6 X 10(-7) M +/- 9% SE, based on competitive) experiments. The binding, however, was complex, probably involving interaction of multiple binding sites on PG with the cell surface. The EC50 (920 micrograms/ml) was similar to the optimal lymphocyte-activating concentration of PG (400-1000 micrograms/ml). The binding correlated with the ability of different PG preparations to stimulate lymphocytes, since only high Mr PG (not low Mr PG preparations, muramyl dipeptide (MDP), or PG pentapeptide) had the ability to specifically bind to lymphocytes, to compete with PG binding, and to stimulate lymphocytes. Also, low Mr PG preparations, MDP, or PG pentapeptide did not inhibit the mitogenic stimulation of lymphocytes by high Mr PG. These results indicate the presence of specific binding sites for PG on the surface of murine lymphocytes and suggest that the binding of PG to these binding sites is involved in lymphocyte activation by PG.

Animals↗
PubMed1987

Modulation of polyclonal activation by plasma fibronectin and fibronectin fragments.

Modulation of activation of polyclonal IgM, IgG and IgM anti-DNA antibodies by plasma fibronectin (Fn) was studied because in some autoimmune diseases there appears to be a correlation between the increased level of Fn in the affected tissues and increased polyclonal B-cell activation. Fn caused a dose-dependent polyclonal activation of IgM, IgG and IgM anti-DNA antibody-secreting cells in cultures of mouse splenocytes. Fn significantly inhibited the generation of polyclonal antibodies by Fn-binding stimulants and did not significantly change the generation of polyclonal antibodies by the stimulants that do not bind Fn. Plasmin or trypsin digestion of Fn abolished both the polyclonal activating properties of Fn and the inhibitory effects of Fn that were selective for the Fn-binding polyclonal activators. Digestion of Fn with trypsin also generated immunosuppressive Fn fragments that inhibited polyclonal activation by both Fn-binding and non-binding bacteria. Under our culture conditions Fn or Fn digests were not mitogenic and had no effect on the mitogenicity of Fn-binding and non-binding stimulants. These results indicate that Fn can act as a polyclonal activator and that it can also modulate lymphocyte activation induced by other activators.

Animals↗
PubMed1985

Ontogenic development of proliferative and polyclonal antibody and autoantibody responses to staphylococcal peptidoglycan, protein A and cell walls in mice.

In the spleens of newborn mice, polyclonal IgM, IgG and IgA responses were low to protein A, cell walls (CW) and PWM, intermediate to peptidoglycan (PG), and high to LPS. Small, not significant increases in Ig responses to LPS (which occurred during the first 2 wks) were observed, whereas, the responses to PG, protein A, CW and PWM continued to increase for 8 wks, and the increases were high and significant. In most cases, there was no change in the dose response and kinetics patterns (characteristic for each stimulant) during ontogeny. Ontogenic development of autoantibody-secreting cells was different from the development of cells secreting all Ig and anti-SRBC antibodies. The increases in the numbers of cells secreting IgM anti-DNA and IgM anti-bromelin-treated mouse RBC antibodies in response to LPS and PG during postnatal development were larger than the increases of all IgM-secreting cells. In contrast, the increases of IgM anti-DNA secreting cells in response to protein A and PWM were smaller than the increases of all IgM-secreting cells. The frequencies of cells secreting anti-DNA antibodies in LPS- and PG-stimulated cultures were low in newborns and continued to increase until 8 wks of age, but they were high and did not change throughout ontogeny in protein A-stimulated cultures. Changes in the frequencies of anti-RBC antibody-secreting cells were less distinct and mostly insignificant. Postnatal changes in mitogenic responses were smaller and not correlated with the development of polyclonal Ig responses. Our data indicate different modes of ontogenic development of the ability of cells to produce polyclonal Ig, autoantibodies and heteroantibodies, and to synthesize DNA, in response to different stimulants.

Animals↗
PubMed1985

The role of DNA synthesis in peptidoglycan-induced generation of immunoglobulin-secreting cells in mice and humans.

The requirement for DNA synthesis in peptidoglycan (PG)-induced activation of polyclonal antibodies has been studied. Inhibition of DNA synthesis with mitomycin C or hydroxyurea at the initiation of the cultures inhibited generation of over 90% of IgM- and IgG-secreting cells in PG-stimulated mouse splenocytes and of over 99.9% of IgM-, IgG- and IgA-secreting cells in PG-stimulated human peripheral blood lymphocytes. Inhibition of DNA synthesis 2 to 4 days after initiation of PG-stimulated cultures (in both mice and humans) caused an immediate decline in the numbers of Ig-secreting cells. These results demonstrate that the magnitude of PG-induced polyclonal antibody response depends on continued DNA synthesis and proliferation of Ig-secreting cells, and indicate that IgM-, IgG- and IgA-secreting cells in polyclonal activation may be actively cycling cells.

Adult↗
PubMed1985

Comparison of in vitro and in vivo mitogenic and polyclonal antibody and autoantibody responses to peptidoglycan, LPS, protein A, PWM, PHA and Con A in normal and autoimmune mice.

We have compared the in vitro and in vivo mitogenic and polyclonal antibody (IgM-, IgG-, IgA- and IgM anti-SRBC-secreting PFC) and autoantibody (IgM anti-ssDNA-, anti-bromelin-treated [HB]- and anti-intact mouse RBC-secreting PFC) responses to peptidoglycan (PG), LPS, protein A, PWM, PHA and Con A in young (4-7 weeks) and old (7-8 months) normal (BALB/c, CBA/H, C57BL/6) and autoimmune (NZB, NZB X NZW F1, BXSB, MRL/1; old BXSB and MRL/1 were 4-5 months) mice. Our results demonstrated that: lymphocytes from young and old autoimmune mice (except old BXSB) could be further polyclonally activated in vitro by PG or LPS as well as or better than lymphocytes from young and old normal mice; lymphocytes from young or old autoimmune mice were less polyclonally activated in vitro by protein A or PWM, respectively, than lymphocytes from young or old normal mice; PG and LPS were equally effective polyclonal activators in vitro; in vivo, LPS was a stronger stimulant than PG; in vivo, LPS could induce polyclonal activation in both young and old normal and autoimmune mice, whereas, PG could only induce polyclonal activation in vivo in young and old normal mice, but did not induce further activation in young and old autoimmune mice; only some tests (anti-ssDNA and IgG PFC in vivo, and IgA and anti-HB MRBC PFC in vitro) revealed higher responses in autoimmune than in normal mice, and these higher responses were seen more often in vivo than in vitro; both autoimmune and normal mice had a high frequency of autoantibody (especially anti-ssDNA) secreting cells in polyclonal activation in vitro, whereas a high frequency of these cells in vivo was only found in autoimmune mice; in most cases in vitro, polyclonal activators did not change the frequency of autoantibody and heteroantibody secreting cells, but in vivo, both PG and LPS increased the frequency of anti-ssDNA antibody secreting cells in normal, but not in autoimmune, mice; LPS increased the in vivo, but not in vitro, frequency of cells secreting anti-HB MRBC antibodies in some strains of mice; old mice had lower mitogenic responsiveness than young mice in both autoimmune and normal strains; autoimmune mice had similar, higher or lower mitogenic responses than normal mice, depending on the strain and the age, but in most cases consistent for both B and T cell mitogens; and there was no correlation between the patterns of increased or decreased mitogenic and polyclonal antibody responses in normal and autoimmune mice.4+.

Age Factors↗
PubMed1979

Mitogenic activity of staphylococcal peptidoglycan.

Staphylococcus aureus peptidoglycan displayed a marked dose-dependent mitogenic activity for mouse splenocytes and human peripheral blood lymphocytes in vitro, as measured by increased [3H]thymidine incorporation. Similarly it was mitogenic for athymic nude mouse spleen cells, whereas no blastogenic effect was observed in T cell-enriched and B cell-depleted mouse lymphocyte cultures. These data demonstrate that peptidoglycan-responding cells in mouse spleen cell cultures are B lymphocytes.

Animals↗
PubMed1979

Relationships between adjuvant, immunosuppressive, and mitogenic activities of staphylococcal peptidoglycan.

Staphylococcal peptidoglycan (PG) possesses in vivo immunodulating activity and is a B-cell mitogen in mice. The effect of PG on in vitro immune response of mouse splenocytes to sheep erythrocytes (SRBC) was studied, as well as the relationships between in vivo and in vitro adjuvant, immunosuppressive, and mitogenic activities of PG in terms of dose response, time kinetics, and physical state. Particulate PG suppressed in vivo anti-SRBC response when injected in a large dose before or simultaneously with SRBC. A small dose of particulate PG given before or along with the antigen was immunostimulatory. Soluble PG was adjuvant active in both high and low doses when injected before or along with the antigen. Both PG preparations were adjuvant active for mouse splenocytes in vitro immunized with SRBC, but particulate PG was more active. Even high doses of particulate PG were not directly suppressive for the in vitro immune response. Particulate PG was also mitogenic for mouse splenocytes, and the maximum increase in [3H]thymidine incorporation was observed after 2 days of culture. Soluble PG was not mitogenic during the 5-day incubation period. These results indicate that the physical state of PG, its dose, and its time of application are important factors determining its immunomodulating and mitogenic activities, and that by changing them it is possible to dissociate the adjuvant, immunosuppressive, and mitogenic properties of PG.

Adjuvants, Immunologic↗