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E W Lamon

Publications and source records attributed to E W Lamon.

At least 37 records · Page 2Linked to original sources
PubMed1989

In vitro effects of ethanol and acetaldehyde on lymphoid cells as determined by 31P NMR spectroscopy.

We have used NMR spectroscopy to test the direct in vitro effects of ethanol and its metabolite acetaldehyde on a human leukemic T cell line (Molt-4) and normal murine spleen cells. The metabolic status of phosphate metabolites (phosphomonoesters including sugar phosphate, inorganic phosphate and ATP's) in cell suspension was monitored by 31P NMR spectroscopy. Spectral changes were observed in the intensity of inorganic phosphate and ATP. Addition of high concentrations of ethanol (400-1600 mM) to Molt-4 cells resulted in very little spectral change. However, the addition of 40 microM acetaldehyde resulted in substantially increased inorganic phosphate (Pi) signals, and decreased phosphomonoesters and ATP signals. Similar changes, but to a lesser degree, were observed with normal mouse spleen cells.

Acetaldehyde↗
PubMed1988

Activation of a functional idiotype network response by monoclonal antibody specific for a virus (M-MuLV)-induced tumor antigen.

BALB/c mice were injected with IgM mAb specific for Moloney murine leukemia virus (M-MuLV)-determined cell surface Ag in an attempt to inhibit Moloney sarcoma growth. The monoclonal IgM significantly inhibited sarcoma growth when given to the mice after inoculation with Moloney murine sarcoma/leukemia virus, and also potentiated the in vivo antibody response specific for M-MuLV Ag. These responses were significantly greater than the primary response to the virus alone in age- and sex-matched control mice, and were also seen in mice which were injected with the IgM antibody only and not with virus, suggesting that an Ag-independent mechanism may be involved. The M-MuLV-specific serum antibody responses induced by the monoclonal IgM, with or without prior virus inoculation, were predominantly of the IgG1 isotype, with some IgG2a; no other isotypes were found to have titers significantly higher than in the normal response to virus alone. M-MuLV-specific IgG1 was detected only in mice injected with monoclonal IgM, and not in the response to virus alone. The same sera also had high titers of anti-idiotypic antibodies, (Ab2), as well as anti-anti-idiotypic antibodies (Ab3). It appears, therefore, that passive immunization with M-MuLV-specific IgM mAb activates an idiotypic network, which results in both Ab2 and Ab3 responses; the M-MuLV-specific response may be considered a subset of Ab3.

Animals↗
PubMed1988

Effects of retinoids on macrophage function and IL-1 activity.

The effects of three retinoids, all-trans-retinoic acid (RA), 13-cis-retinoic acid (cRA), and N-(4-hydroxyphenyl) retinamide (4-HPR), on macrophage function were evaluated. In vitro, RA, cRA, and 4-HPR caused a greater than twofold increase in phagocytosis of IgG-sensitized bovine erythrocytes (IgG-ORBC) by a mouse macrophage cell line (RAW). Significant increases in phagocytosis were produced by retinoid concentrations as low as 2 x 10(-10) M. RA also significantly increased phagocytosis of IgG-sensitized ORBC by BALB/c peritoneal macrophages in vitro. The ability of RAW macrophages to bind IgG-ORBC was significantly increased by 10(-6) to 10(-14) M RA. The potentiation of mitogenic responses of spleen cells to Con A and PWM by RA was relatively independent of macrophage function, i.e., splenocytes that were macrophage-depleted were responsive to the potentiating effects of RA. The effects of retinoids on T-cell-dependent B-cell mitogenesis induced by PWM appeared not to be dependent on their previously reported capacity to alter prostaglandin synthesis. Treatment of spleen cells with 10(-6) M indomethacin did not abolish the potentiating effects of RA. However, RA in a dose-dependent fashion increased IL-1 activity at the level of the target T-cell. The greatest potentiation of IL-1 activity was at 10(-8) M RA. These results show that retinoids can modulate macrophage function at two different levels: potentiation of phagocytosis and potentiation of IL-1 activity at the level of the T-cell.

Animals↗
PubMed1988

Toxicologic and immunologic evaluations of N-(all-trans-retinoyl)-DL-leucine and N-(all-trans-retinoyl)glycine.

Sprague-Dawley rats were dosed by gavage daily for 28 days with 5, 15, or 50 mg/kg of N-(all-trans-retinoyl)-DL-leucine (RL), N-(all-trans-retinoyl)glycine (RG), or all-trans-retinoic acid (RA). On the basis of mortality incidence, fracture incidence, body weight, and histopathologic effects, RG was slightly to moderately less toxic than RA, and RL was significantly less toxic than RA or RG. Doses that had no effect on weight loss and produced no bone fractures were approximately 5 and 15 mg/kg/day for RA administered to males or females, respectively; greater than 15 mg/kg/day for RG administered to males or females; and greater than 50 mg/kg/day for RL administered to males or females. At these doses, RA and RG produced effects, detectable at the microscopic level, of lymphoid hyperplasia and hematopoietic cell proliferation in the spleen, lymphoid hyperplasia in lymph nodes, necrosis of the cortex of the thymus, hypertrophy of the zona fasciculata of the adrenal, a periportal pattern of cytoplasmic vacuolization in hepatocytes, hematopoietic cell proliferation in the liver, epithelial hyperplasia and subacute inflammation in the forestomach, and osteodystrophy. Serological alterations consisted of reduced serum albumin levels and elevated levels of triglycerides and alkaline phosphatase. For RL, similar microscopic effects, dependent on dose level and sex, were observed in spleen, thymus, adrenal, and liver. In vitro, RL was as active as RA in potentiating pokeweed mitogen-induced lymphocyte proliferation; RG was inactive. This study indicates that, relative to RA and RG, RL has less toxicity but similar immunological effects. Since RL and RG expressed little or no binding affinity for cellular RA-binding protein, the immunological effects of these retinoids may be expressed by mechanisms not linked to this protein.

Alkaline Phosphatase↗
PubMed1987

In vitro effects of retinoids on murine thymus-dependent and thymus-independent mitogenesis.

The effects of three retinoids: all-trans-retinoic acid (RA), 13-cis-retinoic acid (13-cis-RA), and N-(4-hydroxyphenyl)retinamide (4-HPR) on murine splenic lymphocyte proliferative responses to mitogens were evaluated. The responses to T-cell mitogens, PHA and Con A, and a T-cell-dependent B-cell mitogen, PWM were significantly potentiated by these retinoids. However proliferative responses to a B-cell mitogen, Escherichia coli LPS were unaffected or inhibited. All three retinoids at concentrations ranging from 10(-6) to 10(-15) M significantly potentiated Con A-induced proliferative responses. In response to PWM, 10(-13) M RA, 10(-12) M 13-cis RA, and 10(-11) M 4-HPR were the lowest concentrations producing significant potentiation. Endpoint concentrations of retinoids significantly potentiating responses to PHA were; 10(-9) M RA, 10(-8) M 13-cis RA, and 10(-6) M 4-HPR. These responses were independent of retinol contained in fetal calf serum supplemented medium since responses were reproduced in serum-free medium devoid of retinol. Optimal potentiation by retinoids of responses to these T-cell-dependent mitogens were found at superoptimal concentrations of mitogen suggesting a selective inhibition of T-suppressor cells. Thus, potentiation of T-cell-dependent mitogen responses provides the most sensitive biological assay yet described for detection of retinoid activity and is a reproducible system to explore the cellular and molecular mechanisms of retinoid-mediated immunopotentiation.

Animals↗
PubMed1987

In vitro effect of ethanol on cell-mediated cytotoxicity by murine spleen cells.

The effects of ethanol on murine spleen cell-mediated lysis have been studied. Concentrations of 5.5-176 mM ethanol produced progressive inhibition of antibody-dependent cell-mediated cytotoxicity (ADCC). Binding of spleen cells to antibody-sensitized target cells was not inhibited by comparable concentrations of ethanol. Kinetic analysis revealed decreased rates of lysis with increasing concentrations of ethanol. Changes of effector to target cell ratios revealed an inhibition of maximum lysis and decreased lytic efficiency in the presence of 88 mM ethanol. Preincubation experiments showed the inhibitory effect of ethanol to be reversible. Macrophage-depleted spleen cells appeared to be as susceptible to inhibition by ethanol as unfractionated spleen cells. Ethanol also inhibited natural killer and alloimmune cytotoxic T cell activity. The ADCC data were analysed by using a mathematical model which incorporates the kinetics of lysis, dose-response relationships, heterogeneity of the lytic effectors, reversibility of inhibition and ethanol loss during incubation. An inhibition constant (KI) of 373 mM-2 when two ethanol molecules interact with the site of inhibition was calculated. 50% inhibition of lysis is produced by 52 mM (0.24%) ethanol. The results are consistent with a model which assumes that lysis is due to a critical number of interactions which ultimately trigger the lytic event. Alcohol interferes with lysis by reacting with sites which are required for triggering the lytic event. Although the molecular details of the mechanism of inhibition are as yet undefined, we infer that ethanol inhibits ADCC at the programming for lysis or the lethal hit stages.

Animals↗
PubMed1987

Monoclonal IgM antibodies that inhibit primary Moloney murine sarcoma growth.

Monoclonal IgM antibodies with specificity for Moloney murine sarcoma virus (M-MuSV)-Moloney murine leukemia virus (M-MuLV) from two hybridoma clones have been isolated and characterized. The monoclonal antibodies have specificity for a cytoplasmic and cell surface Friend-Moloney-Rauscher group-specific antigen. Immunoelectron microscopy revealed antibody binding to the surface of virus-expressing cells but not to the budding virus particles. Treatment of M-MuSV-injected mice with monoclonal IgM anti-M-MuSV significantly inhibited tumor growth compared to virus-inoculated animals receiving either saline or MOPC 104E. Nude mice exhibited delayed tumor induction following treatment with the monoclonal antibodies but ultimately died from tumor growth. Virus-injected euthymic mice that were treated with monoclonal IgM anti-M-MuSV generated a potentiated spleen cell-mediated cytotoxicity against Moloney sarcoma cells compared to virus-infected treated with saline. This potentiation of cytotoxicity remained after trypsinization of the spleen cells and thus was probably not due to passively adsorbed monoclonal antibody. The antibodies alone or in the presence of complement did not neutralize M-MuLV. The IgM antibodies induced specific tumor cell cytotoxicity in vitro mediated by complement spleen cells, lymph node cells, or thymus cells. In conclusion, two monoclonal IgM anti-M-MuSV antibodies that bind to the tumor cell surface did not neutralize virus can inhibit primary M-MuSV-induced tumor growth in vivo. The regression event appeared to involve heterogeneous mechanisms. Complete regression remained thymus dependent even with passive antibody therapy, but significant tumor growth inhibition was produced independent of T-cells. In vitro these IgM antibodies induced complement and cell-mediated cytotoxicity.

Animals↗
PubMed1986

Simultaneous expression of multiple immune complex receptors on murine thymocytes and spleen cells.

Mixed rosette studies were performed to evaluate the coexpression of IgG Fc. IgM Fc, and complement receptors (C3R) by thymocytes obtained from mice 7 days after cortisone injection and by spleen cells. Indicator cells coated with IgM, IgG, or C3 independently were mixed and could be distinguished by morphology or by a fluorescein label. In double-marker studies, 36% of spleen cells formed rosettes with IgG- and/or IgM-sensitized red blood cells. Among this population there was a 24% overlap of cells binding IgM and IgG complexes simultaneously. Of the spleen cells, 78% bound IgM- and/or C3-sensitized cells. Of the spleen cells forming rosettes with IgM and C3 indicator cells, 15% coexpressed these receptors. With IgG and C3 indicator cells, 58% of spleen cells bound to one or both kinds of complexes with an 18% overlap. Of cortisone-resistant thymocytes, 14% formed rosettes with IgM- and/or IgG-sensitized red blood cells; within this population there was an overlap of 21%. With IgM- or C3-sensitized cells, 19% of cortisone-resistant thymocytes bound to one or both, among which there was a coexpression of 21%. With IgG- or C3-sensitized cells, there was a 14% overlap of rosette-forming cells binding both. In triple-marker studies 79% of spleen cells formed rosettes with C3-, IgG-, and/or IgM-sensitized indicator cells, out of which 11% coexpressed IgM and IgG FcR, 20% coexpressed IgG and C3R, and 10% coexpressed IgM FcR and C3R. Of rosette-forming cells, 13% coexpressed all three receptors. With cortisone-resistant thymocytes, 19% bound one or more kinds of immune complexes. Among these, 9% coexpressed IgG FcR and C3R, 14% coexpressed IgM FcR and C3R, and 14% bound IgG and IgM complexes. We could not detect the simultaneous expression of all three receptors on cortisone-resistant thymocytes. Using Isopaque-Ficoll fractionation of cells binding C3-sensitized cells, cortisone-resistant thymocytes were enriched and depleted of C3-receptor-bearing cells and their Lyt phenotypes were determined by immunofluorescence microscopy. The C3-receptor-enriched population contained 56% C3R+ cells which were 79% Lyt-1 positive and 100% Lyt-2 positive. The C3R-depleted population contained 1.3% C3R+ cells with 10% Lyt-1 positive and 22% Lyt-2 positive among the total. Surface phenotypic expression of normal and cortisone-resistant thymocytes was also evaluated by direct and indirect fluorescence by fluorescence-activated cell sorter (FACS).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

Avidities of hapten-specific antibodies when the responses are modulated by anti-carrier antibodies.

Either alone or in combination with antibodies having specificity for the carrier erythrocyte, TNP-ORBC were injected i.p. into CBA/J mice. Five days later, their spleens were removed and evaluated for TNP-specific PFC. The spleens from animals receiving 19S antibody (IgM) with carrier specificity displayed 3-4-fold more direct and indirect hapten-specific PFC than control animals receiving the TNP-erythrocyte conjugate only. Animals receiving 7S antibodies (IgG) with carrier specificity displayed very little change in their direct PFC response to the hapten. However, the indirect response to the hapten was suppressed as much as 16-fold by carrier specific IgG. Evaluation by haptenic inhibition of the relative avidity of the antibodies being secreted by these cells revealed the following: the relative avidity of antibodies secreted by indirect PFC in the spleens of animals receiving TNP-ORBC only was approximately 20-fold higher than antibodies secreted by the direct PFC. The 3-4-fold potentiation of the hapten-specific PFC response by carrier-specific IgM antibody did not result in a change in relative avidity of direct or indirect PFC. IgG with carrier specificity did not change the relative avidity of the antibodies secreted by direct PFC having specificity for the hapten. However, evaluation of the remaining PFC in spleens from animals whose indirect hapten-specific PFC response had been suppressed by carrier-specific IgG revealed that the remaining PFC had a lower avidity than indirect PFC from animals receiving TNP-ORBC only. In other words, carrier-specific IgG selectively induced suppression of high avidity hapten-specific IgG antibody secreting cells.

Animals↗
PubMed1983

Potentiation of antibody responses by specific IgM: specificity and thymus dependency.

Modulation of antibody responses induced by IgM directed against the immunogen was investigated. When IgM directed against ox erythrocytes (ORBC) was given together with trinitrophenyl (TNP)-ORBC, the subsequent antibody response to the carrier, ORBC, as well as the response to the hapten, TNP, was potentiated. In contrast, IgG with carrier specificity inhibited both responses. The hapten-specific potentiation was found in both direct and indirect plaques, and was antigen-dose dependent, i.e., no potentiation was found with the lowest antigen doses. The response to 2,4-dinitrophenyl (DNP)-labeled proteins was potentiated by a monoclonal IgM with specificity for the hapten. The effects were observed both in primary and secondary responses. One strict requirement for IgM potentiation to occur was observed. The determinant against which potentiation was achieved had to be physically linked to the determinant against which the IgM was directed, be it hapten or carrier determinants. Thus, irrelevant IgM-antigen complexes were incapable of potentiating the responses. Similar specificity requirements were found for IgG induced suppression of antibody responses. Experiments with nude mice and their euthymic littermates showed that IgM potentiation of antibody production is T-cell dependent. Furthermore, passive transfer of carrier-primed spleen cells together with antigen challenge suggests that IgM potentiation of secondary antibody responses is dependent on specific carrier-primed immune T cells.

Animals↗
PubMed1983

Effects of DNA synthesis inhibitors on early antigen expression following primary infection or superinfection by Epstein-Barr virus.

Seven lymphoid cell lines previously characterized with respect to their resident Epstein-Barr virus (EBV) genome content were infected or superinfected with concentrated EBV from supernatant of the P3HR-1 cell line. Immunofluorescence assays were conducted on smears 48 hours after infection, using human sera containing antibodies to EBV early antigen (EA). Two EBV nuclear antigen (EBNA) negative cell lines containing no detectable resident EBV DNA and five EBNA positive cell lines containing EBV genomes were tested. The cell lines did not spontaneously express EBV EA (i.e., they were non-producers). All cell lines responded to infection or superinfection with EBV by expressing EA. Treatment of the cell lines with arabinosylcytosine (Ara-C) 10 micrograms/ml, at the time of infection resulted in significant decreases in the number of cells expressing detectable EA after drug treatment in all cell lines (72 +/- 5 percent inhibition of EA expression). Experiments were also conducted with hydroxyurea (HU) and phosphonoacetic acid (PAA). It was found that treatment with HU (100 micrograms/ml) inhibited EA production in cell lines containing EBV genome copies by 81 percent as compared to the superinfected cultures receiving no drug. In primary infection of EBNA negative cell lines, HU had minimal effects. PAA (100 micrograms/ml), on the other hand, had very little effect on EA expression following superinfection of cell lines harboring the EBV genome, but reduced the EA expression after primary infection of EBNA negative cell lines by 70 to 80 percent. All drugs were used at concentrations having little effect on RNA and protein synthesis. However, HU and Ara-C significantly reduced DNA synthesis and cell division in the treated cultures.

Antigens, Viral↗
PubMed1983

Characterization of effector cells mediating IgG and IgM antibody-dependent cellular cytotoxicity.

Spleen effector cells for IgG- and IgM-induced antibody-dependent cellular cytotoxicity (ADCC) were characterized with respect to density and cell surface markers by using sheep erythrocytes (SRBC) coated with hybridoma-derived monoclonal anti-SRBC IgG or anti-SRBC IgM antibodies as targets. While basically the same effector cells are cytolytic for IgG and IgM antibody-coated SRBC, they differ with respect to their relative killing capacity for IgG- versus IgM-coated target cells. On the basis of physical and biochemical properties three populations with cytolytic capacity could be separated: (I) A light fraction of large cells had high cytolytic potential for both IgG- and IgM-coated SRBC. The cells were negative for the Fc receptor for IgG (Fc gamma-R-) and the C3-receptor (C3-R-), they carried the receptor for Helix pomatia A agglutinin (HP-A+), and reactivity was strongly reduced after treatment with anti-Thy-1 and complement (C). (II) High activity was also observed with a medium-dense fraction, preferably lysing IgG antibody-coated cells. The cells were Fc gamma-R+, partly C3-R+, mostly HP-A-, and only a minor portion of the cells were Thy-1+. (III) A dense fraction, displaying on a per cell basis low cytolytic potential, was more active in IgM than IgG ADCC. The cells were Fc gamma-R+, HP-A+ and Thy-1+. All three effector cell populations were non-adherent, non-phagocytic, and surface immunoglobulin-negative (s-Ig-).

Animals↗
PubMed1982

Immunologic studies on the influenza A virus nonstructural protein NS1.

We purified the major influenza virus nonstructural protein, designated NS1, from cytoplasmic inclusions that were solubilized and used to raise antisera in rabbits. One of the antisera was found to be specific for NS1 by complement fixation tests and analyses of immune precipitates. Antiserum to NS1 isolated from cells infected with A/WSN/33 virus specifically precipitated NS1 from extracts of cells infected with seven distinct isolates of influenza A virus representing five different antigenic subtypes. These included A/WSN/33, A/PR/8/34, A/FW/5/50, A/USSR/90/77, A/RI/5+/57, A/Victoria/3/75, and A/Swine /1977/31; however, NS1 from cells infected with B/Lee/40 virus was not precipitated. Radioimmunoassays using radioiodinated NS1 protein from A/WSN virus-infected cells and unlabeled cytoplasmic extracts of cells infected with various strains of influenza virus as competitors indicated significant antigenic cross-reactivities for the NS1 proteins of all influenza A viruses tested. The results suggest a gradual antigenic drift over the 45 yr separating the earliest and most recent virus isolates examined. Thus, compared with the virion neuraminidase and hemagglutinin antigens, NS1 appears to be highly conserved in different influenza A virus isolates.

Animals↗
PubMed1982

Immune response to polyoma tumor cells in mice--III. Stimulation of tumor cell growth in vitro by spleen cells from immunized animals.

We have evaluated the stimulation of target cell growth in vitro by spleen cells from mice which were immunized with polyoma-transformed cells and other tumor and non-tumor antigens. Stimulation was particularly seen under conditions of immunization that were suboptimal for the production of specific cytotoxicity. Significant stimulation of polyoma target cell growth was observed by lymphocytes from mice immunized against 10(5) Py 4198 tumor cells. This stimulation of target cell growth was not confined to polyoma-transformed cells only. Cells transformed by SV40, H-MuSV and non-transformed cells like 3T3 and embryo fibroblasts were also stimulated. Immunization of mice with syngeneic embryo fibroblasts also resulted in stimulation of tumor cell growth by the spleen cells from the immunized mice. However, the growth stimulation was less consistent and did not occur in all target cells tested. The specificity of immunostimulation was further studied with the Moloney sarcoma virus (M-MuSV) system; an antigenically distinct tumor system. Spleen cells from M-MuSV tumor-bearing mice stimulated cell growth in vitro not only against MuSV-transformed cells but also with SV40-transformed and polyoma-transformed cells as targets. Significant stimulation of target cell growth was also observed by spleen cells from mice that were immunized against 'non-pertinent' antigens, e.g. sheep red blood cells and allogeneic (C57B 1/6) spleen cells.

Animals↗
PubMed1982

Antiviral effects of interferon on a somatic cell hybrid between two Burkitt's lymphoma cell lines of different interferon sensitivities.

A somatic cell hybrid between two human Burkitt's lymphoma cell lines, Raji and Daudi, was infected with either Epstein-Barr virus or vesicular stomatitis virus after interferon treatment. Raji cells are resistant to the antiviral effects of exogenously added interferon, whereas Daudi cells are interferon sensitive. The Raji-Daudi hybrid showed an interferon sensitivity that was intermediary to that of the parental cells against both viruses.

Burkitt Lymphoma↗
PubMed1982

Complementation between infecting Epstein-Barr virus and intrinsic viral genomes in human lymphoid cell lines.

13 human lymphoid cell lines previously characterized in terms of their intrinsic Epstein-Barr virus (EBV) genome content were infected or superinfected with EBV from the supernatant of P3HR-1 cells. The cell lines included 2 lymphoma cell lines that contain no detectable EBV genomes and 11 cell lines containing intrinsic EBV genomes. All the cell lines responded to EBV infection by expressing early antigen (EA). The number of EA-positive cells in the cultures was proportional to the viral concentration used for infection or superinfection. However, cell lines containing multiple intrinsic EBV genomes expressed higher amounts of EA-positive cells. Evaluation of EA expression versus the number of intrinsic EBV genome copies per cell in each line revealed EA to increase as the intrinsic EBV genome content of the cell lines increased in a nonlinear curve that was described by an exponential logistic function. The coefficient of determination R2 for this curve was greater than 0.9 for multiple experiments. The data suggest that 80-90% of the virus in P3HR-1 is defective and requires intrinsic viral genomes for expression of EA. Transactivation or complementation between intrinsic EBV genomes and infecting virus is supported by these observations.

Antigens, Viral↗