Search PubMed⌕ Search

Biomedical subjects

G J Stanton

Publications and source records attributed to G J Stanton.

At least 37 records · Page 2Linked to original sources
PubMed1985

Virus-specific, early appearing neutralizing activity and interferon in tears of patients with acute hemorrhagic conjunctivitis.

Virus-specific, early appearing neutralizing activities (ENA) and interferon (IFN) were detected in tears collected from patients during epidemics of acute hemorrhagic conjunctivitis (AHC). In one study, ENA that neutralized enterovirus type 70 (EV70) was detected in tears collected from 114 of 130 AHC patients in Florida. In another study, ENA against coxsackievirus type A24 (CA24) was detected in tears collected from 39 of 57 patients in Singapore with AHC caused by CA24. No tear samples contained ENAs to both EV70 and CA24. Tear samples from uninfected eyes did not contain ENA to EV70 or CA24. ENA to EV70 was detected in 6 of 11 patients 1-6h before the onset of AHC. In addition, tears of 68% of patients seen on the day of onset produced tears that contained ENA to EV70. Thus, ENA to EV70 may be detected less than 24h after infection (based on 24h incubation period). IFN beta was detected in 30% of tear samples collected from patients on the day of onset of AHC caused by EV70. This finding suggested that ENA and IFN could act together to inhibit primary infections of AHC. It was found that the combination of ENA and IFN inhibited virus replication synergistically (greater than or equal to 300 fold reduction) in preinfected cells. Our findings suggest that ENA represents a previously unreported early defense mechanism of the eye, that endogenous ENA and endogenous IFN could inhibit viruses synergistically in vivo, and that ENA in tears could be useful in identifying the agent causing AHC.

Acute Disease↗
PubMed1985

Interferon-induced transfer of natural cytotoxic activity between human leukocytes.

Interferon (IFN) caused the transfer of natural cytotoxic activity between human leukocytes in a syngeneic system. The transfer of cytotoxic activity was found to be dependent on the cell density and was in proportion to the IFN concentration. Human immune-type IFN (IFN-gamma) was more efficient than IFN-alpha or IFN-beta in eliciting the transfer of cytotoxic activity. The transfer occurred with IFN-gamma preparations of various specific activities and with recombinant IFN-gamma. The transferred activity had the characteristics of an IFN-induced antiviral state, in that it was blocked either by actinomycin D or by prevention of cell contact. Specific antibodies to IFN had no effect on the transfer of cytotoxic activity. Protection of mouse target cells from human cytotoxic activity could also be transferred from IFN-induced human foreskin fibroblasts (HFF) insensitive to cytotoxic activity to the cytotoxic-sensitive mouse cells. The transfer of protection was highly efficient at ratios of one HFF cell to 16 mouse target cells. The transfer of cytotoxic activity, and protection from cytotoxic activity, may represent a mechanism for amplification of the IFN system as a host defense against viral-infected or tumor cells.

Animals↗
PubMed1984

Interferon production and tumor cell killing by human lymphocytes stimulated in mixed-lymphocyte culture.

The in vitro synthesis of interferon (IFN) by human lymphocytes stimulated in mixed-lymphocyte culture (MLC) was examined. The production of IFN in MLC was restricted to T lymphocytes and maximum levels of IFN were detected in supernatants from cells incubated for 5 to 7 days. The IFN produced was identified as IFN-gamma by antibody neutralization. To identify the T cell responsible for IFN production, purified T lymphocytes were separated into subpopulations after incubation in 5 mM theophylline. Theophylline-resistant (T-res) T cells retain the ability to form sheep erythrocyte (SRBC) rosettes and are depleted in IgG Fc receptor-positive T cells (T gamma cells). Theophylline-sensitive (T-sens) T cells fail to form rosettes after theophylline treatment and are enriched in T gamma cells. In addition, analyses using monoclonal antibodies showed that T-sens cells were enriched in OKM1-, HNK-1-, and 7.2-positive cells and T-res cells contained increased numbers of 9.6- and OKT4-positive cells. Following MLC stimulation, equivalent levels of IFN-gamma were produced by T-res and T-sens cells and both subpopulations maintained natural killer (NK)-like cytotoxicity against K562 target cells. Addition of partially purified IFN-gamma to unstimulated T-res and T-sens cells resulted in the maintenance of NK-like cytotoxicity in a manner analogous to that observed after MLC. Additional experiments indicated that peripheral blood lymphocytes depleted of 9.6- or OKM1-positive cells by complement-mediated lysis were devoid of cytotoxicity against K562 cells. Furthermore, MLC stimulation of 9.6- or OKM1-depleted cells failed to restore cytotoxic activity. In summary, these experiments demonstrate that the maintenance of NK-like cytotoxicity by MLC-stimulated T cells is associated with the synthesis of IFN-gamma, that MLC stimulated T-res and T-sens T-cell subsets produce equivalent amounts of IFN, and that 9.6- or OKM1-positive cells are required for the maintenance of NK-like cytotoxicity in MLC.

Antibodies, Monoclonal↗
PubMed1984

Interferon-induced transfer of viral resistance by human B and T lymphocytes.

Enriched human B lymphocytes cocultivated with mouse L cells produced human leukocyte interferon (IFN-alpha) and shortly thereafter transferred antiviral activity to the recipient cells (99% inhibition of expected virus yield). In contrast, cocultivation of enriched T-cell populations with mouse L cells resulted in no IFN production or transfer of antiviral activity. In addition, both T and B lymphocytes pretreated with exogenous IFN or stimulated in vitro by mitogens could transfer antiviral activity to human WISH cells. The transfer of antiviral activity was not blocked by antibodies to IFN. The data indicate that both T and B cells can be recruited by IFN to transfer antiviral activity. Thus, once cells are recruited by IFN they can transfer antiviral activity in the absence of IFN and protect cells locally or distally from the site of infection.

Animals↗
PubMed1984

Induction of human gamma interferon by structurally defined polypeptide fragments of group A streptococcal M protein.

The presence of interferon (IFN) has been demonstrated previously (i) in fluids obtained from the middle ears of children with Streptococcus pneumoniae infections, (ii) from the serum of mice injected intraperitoneally with either S. pneumoniae or Streptococcus pyogenes, and (iii) from human lymphoid cell cultures treated with a variety of bacteria. In this study, we showed that highly purified peptic extracts of three different serotypes of group A streptococcal M protein (pep M5, pep M6, and pep M24) stimulated human peripheral leukocytes to produce IFN. IFN production was apparent by 10 h and peaked 24 h after exposure. Dose-response experiments indicated that IFN could be detected in cultures treated with concentrations of M protein as low as 6 micrograms/ml, whereas maximum IFN production occurred at a concentration of 200 micrograms/ml. The IFN had antigenic and physicochemical characteristics of IFN-gamma. Preliminary leukocyte fractionation studies revealed that the IFN-producing cell was a nonadherent lymphocyte with receptors for sheep erythrocytes (T cell). Rabbit antisera specific for these structurally defined polypeptide fragments of streptococcal M protein (pep M5, pep M6, and pep M24) blocked IFN induction by each of the polypeptides. The data suggest that the different serotypes of streptococcal M protein may induce IFN by a common structural determinant shared by each of the polypeptide fragments tested.

Amnion↗
PubMed1984

Synergism of antiviral activity in cell cultures treated with low concentrations of interferon and interferon-treated lymphocytes.

Human T cells treated with low levels of interferon (IFN) (1-10 units/ml), and washed to remove the IFN, transferred the same level of antiviral activity to recipient WISH cells as an equivalent IFN treatment alone could induce in WISH cells. Further, when T cells pretreated with IFN (1-10 units/ml) were cocultivated with WISH cells in the presence of IFN (1-10 units/ml), a 2.5- to 5-fold greater level of protection developed than could be expected from the additive effect of each. Antibody to leukocyte, fibroblast, or immune IFN blocked the antiviral effect of the respective IFN types but had no effect on the transfer of antiviral activity initiated by leukocyte, fibroblast, or immune IFN. Also, treatment of T cells with actinomycin D blocked the transfer of antiviral activity of IFN-treated T cells. Taken together, the data suggest that the increased antiviral activity is not merely an additive effect of the IFN, but represents a synergistic amplification of protection most likely due to the combination of the separate effects of IFN and IFN-induced transfer. Such interactions would be expected to play a major role in early protection against virus infections in vivo when low levels of interferon are present and lymphocytes are migrating into the area.

Amnion↗
PubMed1984

Eradication of cultured human melanoma cells by immune interferon and leukocytes.

For the determination of the conditions for the most effective cytolysis of human melanoma cells, leukocyte interferon (IFN-alpha), fibroblast interferon (IFN-beta), and immune interferon (IFN-gamma) were compared for their abilities to kill cultured human melanoma cells in the presence and absence of peripheral blood mononuclear leukocytes (PBL). A microassay was employed in which the viability of melanoma target cells was determined after various times of incubation with interferons alone or with PBL. On 7 human melanoma cell lines (from 6 different patients), IFN-gamma had significantly greater direct anticellular effect than IFN-alpha or IFN-beta. When PBL were added, all target cells were killed after 48 hours with IFN-gamma, but they were not killed with IFN-alpha or IFN-beta. When IFN-gamma was added to either IFN-alpha or IFN-beta, a potentiation of the anticellular effect was observed both with and without PBL. The actions of this "natural" IFN-gamma could be reproduced with recombinant IFN-gamma and could be neutralized by an antibody to a synthetic peptide encoded by the 5'-end of IFN-gamma complementary DNA. It was concluded that IFN-gamma is significantly more active against these human melanoma cell lines than either IFN-alpha or IFN-beta and, most significantly, that eradication can occur in the presence of IFN-gamma and PBL. Furthermore, synergistic anticellular action can be observed when IFN-gamma is added to IFN-alpha or IFN-beta. These findings point to the need for preclinical trials to evaluate eradication in vivo.

Cell Line↗
PubMed1983

Antibodies to a synthetic peptide corresponding to the N-terminal end of mouse gamma interferon (IFN gamma).

Antibodies to an N-terminal synthetic peptide of mouse gamma interferon (MoIFN gamma) neutralized the antiviral activity of MoIFN gamma but not MoIFN alpha/beta, human IFN alpha (HuIFN alpha), HuIFN beta or cynomologus monkey IFN gamma (CynIFN gamma). Comparatively, antibodies to mouse N-terminal synthetic peptide showed only 10% reciprocal cross-reactivity in neutralization tests against heterologous HuIFN gamma and 13% cross-reactivity in the ELISA test against Hu N-terminal peptide. The predetermined specificity of these antibodies make them powerful tools for studying antigenic relatedness and biological properties of IFN gamma s.

Animals↗
PubMed1983

Cell-to-cell transfer of interferon-induced antiproliferative activity.

Interferon-treated cells rapidly and efficiently transferred the antiproliferative activity of interferon to untreated cells. This phenomenon was not due to the carry-over of interferon by the interferon-treated cells. Thus, to evoke an antiproliferative state, interferon did not directly contact each cell in a population. The results suggest a novel mechanism by which interferon may indirectly regulate cell growth, and suggests that cells other than those of the immune system may play a role in controlling tumor growth in tissue where cell-to-cell contact occurs.

Animals↗
PubMed1983

Serum interferon in Navajo children with severe combined immunodeficiency disease inhibits lymphoblastogenesis.

Two Navajo Indian children with severe combined immunodeficiency disease (SCID) lost reconstituted immune function after virus infections. A serum factor which inhibited normal lymphocyte response to mitogens was found in one of them and led to the examination of sera from five other Navajos with SCID. Mean inhibition by six Navajo sera was 67%; no inhibitor was found in sera from normal adults and children. The inhibitor activity was nondialyzable and heat stable, yet partially sensitive to pH 2.0, suggesting that interferon(s) was present. Interferon (IFN) activity in patient sera ranged from 10 to 300 U/ml. Normal children had peak serum IFN levels of 100 and 30 U/ml in the acute and convalescent periods, respectively, of virus infections. IFN alpha, IFN beta, and IFN gamma were identified in SCID sera by specific antisera. Both inhibitor and IFN activities in three Navajo sera were 88-95 and 89-100%, respectively, removed with anti-IFN antisera. Similar patterns of inhibition of lymphoblastogenesis were seen with IFN standards. IFN levels in the SCID patients did not correlate with documented infections; elevated levels were present when no infections could be documented. The immunologic imbalances in some forms of SCID may be related to circulating inhibitors, possibly interferon.

Arizona↗
PubMed1983

Potentiation of lymphocyte natural killing by mixtures of alpha or beta interferon with recombinant gamma interferon.

Human lymphocytes were treated with human alpha (IFN-alpha), beta (IFN-beta), or recombinant gamma (IFN-gamma) interferons separately or in combination to determine their ability to enhance natural killing against mouse L cell targets. Our results showed that recombinant IFN-gamma was approximately 50 times more active per unit of antiviral activity than either IFN-alpha or IFN-beta. Moreover, the levels of natural killing by lymphocytes treated with combinations of IFN-alpha and IFN-beta were additive, whereas combinations of recombinant IFN-gamma and IFN-alpha or recombinant IFN-gamma and IFN-beta were synergistic. The development of natural killing in lymphocytes treated with recombinant IFN-gamma did not occur more rapidly but reached higher levels (62%) than that observed with lymphocytes treated with IFN-alpha or IFN-beta (15%). The results suggest the importance of IFN-gamma and mixtures of IFN-gamma with IFN-alpha or IFN-beta in the enhancement of natural killing activity against virus infections and neoplasia.

Adjuvants, Immunologic↗
PubMed1983

Antibody and interferon act synergistically to inhibit enterovirus, adenovirus, and herpes simplex virus infection.

The possibility that interferon (IFN) and antibody could act together to reduce virus yields in infected cells was suggested by the simultaneous occurrence of IFN and antibody at infected sites. In the present in vitro studies, mixtures of IFNs and antibody acted synergistically to reduce virus yields in cultures infected with coxsackievirus A24, enterovirus 70, adenovirus, and herpes simplex virus. This synergistic reduction was observed in different cells and at different concentration of IFN and antibody. Although IFN and antibody acted synergistically against all viruses tested, the degree of synergism was dependent on the type of IFN or the virus. For example, IFN-beta and antibody was 10 to 200 times more effective than IFN-gamma and antibody against coxsackievirus A24, enterovirus 70, and adenovirus. A combination of antibody and IFN-gamma was three to five times more effective than IFN-beta and antibody against herpes simplex virus. In addition, we found that endogenously produced IFN-beta could act synergistically with antibody to coxsackievirus A24 to increase the overall antiviral effect by 10(5.0)-fold. No effect of endogenous IFN was observed in herpes simplex virus-infected cultures treated with antibody to herpes simplex virus. These studies indicate the potential importance of the synergistic effect of locally produced IFN and antibody in restricting virus early in the natural infectious process. They also suggest that combinations of IFNs and antibody may be more beneficial in the treatment of certain virus infections than IFN or antibody alone.

Adenoviruses, Human↗
PubMed1983

Interleukin 2 enhances natural killer cell activity through induction of gamma interferon.

Highly purified interleukin 2 (IL 2), free of interferon activity, enhanced natural killer (NK) cell activity against tumor cells in mouse spleen cell cultures and in human peripheral lymphocyte cultures in a manner similar to that of interferon (IFN). We determined that IL 2 enhanced NK activity indirectly in a cascade manner by the induction of gamma IFN (IFN-gamma) in the cultures, which actually mediated the enhanced killing. Accordingly, lymphocyte cultures treated with IL 2 alone produced 10 to 100 U of IFN per ml in 6 to 24 h of culture. The IFN was typed as IFN-gamma by specific antibodies. Specific antibodies either to natural IFN-gamma or to a synthetic peptide corresponding to the human IFN-gamma N-terminal amino acids, when added to cultures treated with IL 2, completely blocked IL 2 enhancement of NK cell activity for both the mouse and human systems. IL 2-induced proliferation was not affected by the antibodies. Thus, the enhancement of NK cell activity by IL 2 is completely mediated by IL 2-induced IFN-gamma. The findings clearly indicate a cascade effect whereby one lymphokine (IL 2) induces the production of another. The latter lymphokine (IFN-gamma) then mediates an important biological effect (natural killing).

Animals↗
PubMed1983

Microassay for Sindbis virus and interferon activity.

A simple and rapid microplaque assay for Sindbis virus was developed which uses microtiter plates and overlay medium consisting of methylcellulose and specific antibody to Sindbis virus. Discrete plaque formation was consistently observed on baby hamster kidney (BHK-15) cells within 24 h. The assay was reproducible, quantitative, and had about the same sensitivity as the agar overlay technique on chicken embryo cells in 35-mm petri dishes. The microplaque assay could be accurately applied to measuring interferon activity, particularly at low interferon levels. Overall, the microassay methods described here for assay of Sindbis virus yields and interferon activity retain the accuracy of chicken cell macroplaque assays while offering greater simplicity, rapidity, and economy of materials. This assay is also potentially applicable for use with other togaviruses.

Antibodies, Viral↗
PubMed1983

Ocular herpes simplex virus infection is diminished by depletion of B lymphocytes.

Rabbit anti-mouse mu-chain serum was used to deplete specifically IgM-bearing B cells and B cell function in BALB/c mice. B cell-depleted and normal littermates were infected via the cornea with herpes simplex virus type 1 (HSV-1) at 4 to 5 wk of age. B cell-depleted mice had a reduced number of lymphocytes bearing surface immunoglobulin and a greatly reduced ability to produce antibody. Mortality was reduced from 89% in normal controls to 42% in B cell-depleted mice (p less than 0.001) and peak virus shedding from eyes was also reduced as much as 90% in the B cell-depleted mice (p less than or equal to 0.0005). These results support the hypothesis that a B cell function of normal mice somehow contributes directly or indirectly to the enhanced mortality of mice infected with HSV.

Animals↗
PubMed1982

Positive self regulation of cytotoxicity in human natural killer cells by production of interferon upon exposure to influenza and herpes viruses.

Augmentation of natural killer (NK) activity by influenza A/PC and HSV-1 viruses appears to be caused by the induction of interferon (IFN) within the NK cell population itself. These viruses induced high levels of IFN production by human large granular lymphocytes (LGL) that could be readily isolated from peripheral blood by Percoll density gradients. These LGL, which have been previously shown to account for and to be highly associated with endogenous NK activity, became augmented in their lytic function during the 18-h period that IFN was induced. Non-LGL helper cells did not appear to be required in the NK-IFN system (either T cells, B cells, or monocytes). Removal of these latter cell types by treatment with OKT3 plus complement, anti-IgM plus complement, or preincubation with silica or carrageenan had no effect on the ability of LGL to respond to the viruses. Production of IFN was also detected, albeit at lower levels, from monocytes cultured for 18 h with viruses, but no cytotoxic activity was induced. On the other hand, T cells, even in the presence of monocytes, showed neither property, and longer cultures, with virus up to 4 d, still did not alter the pattern. The IFN produced by both LGL and monocytes were predominantly IFN-alpha, as assessed by neutralization assays with antisera to IFN-alpha, -beta, and -gamma. In an individual with detectable serum antibodies to influenza A/PC, however, the IFN induced in LGL appeared to be gamma, presumably because of specific recognition of the virus. These data suggest an efficient positive self-regulatory mechanism in NK cells that may be readily switched on by viruses.

Antibodies, Monoclonal↗