Cardiac troponin-I: a biochemical marker for cardiac cell necrosis.
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Animals↗
Biomedical subjects
W H Stimson
Publications and source records attributed to W H Stimson.
Molecular recognition in antibodies and its application.
The structure and function of immunoglobulins, and the nature of the antibody-antigen interaction are described. Applications of the molecular recognition properties of antibodies are discussed in the areas of immunotherapy, immunoassay, immunotargeting and catalytic antibodies.
Animals↗
Catalytic antibodies: a new window on protein chemistry.
Catalytic antibodies have created a new dimension in protein chemistry. In these studies it is particularly valuable to investigate systems for which natural enzymic catalysts are unknown. At Strathclyde we have examined several ways of preparing homochiral building blocks for organic synthesis. Antibodies that catalyse the Diels-Alder reaction have been characterized. The target reaction was the addition of acetoxybutadiene to N-substituted maleimides, a reaction that should give a pentafunctional homochiral building block. Catalytic antibodies can give insight into the mechanism of catalysis by proteins. We have investigated an adventitious hydrolytic antibody that cleaves activated esters. We have also shown that an antibody raised to ampicillin for analytical purposes catalyses hydrolysis of the beta-lactam ring.
Animals↗
Interleukin-6 enhances the induction of human lymphokine-activated killer cells.
Human peripheral blood mononuclear cells develop a powerful lytic capacity when cultured in vitro with interleukin-2 (IL-2), becoming lymphokine-activated killer cells (LAK cells). As part of an investigation into means of influencing this process, the effect of other cytokines has been examined. In this study we describe the ability of interleukin-6 (IL-6) to regulate the induction and function of human LAK cells. The results show that substitution of IL-6 for IL-2 did not lead to the development of functional LAK cells, nor was IL-6 able to alter the lytic capacity of established LAK cells. However, when IL-6 was included with IL-2 during the induction phase of the LAK cells, the resulting cells displayed considerably greater lytic activity than those prepared with IL-2 alone. This effect was IL-6 dose-related. These results indicate that LAK cell development may be positively regulated in vitro; the implications of this observation for the clinical usage of LAK cells are discussed.
Cells, Cultured↗
Oestrogen receptors in macrophages.
The presence of receptors for oestradiol-17 beta and 5 alpha-dihydrotestosterone (5 alpha-DHT) in the human monocytic leukaemia cell line J111 and rat peritoneal macrophages was investigated using whole-cell assays. For both cell types, high-affinity binding species for oestrogen were detected, whereas no indication of specific binding was observed for 5 alpha-DHT. Analysis of the data according to Scatchard showed curved lines, indicating the presence of two different oestrogen-binding species. The dissociation constant (Kd) values for the receptors of the rat peritoneal macrophages were calculated to be 1.4 x 10(-10) M and 3.3 x 10(-9) M, while for the J111 cells, the Kd values were 8.7 x 10(-11) M and 2.5 x 10(-9) M. Sucrose-gradient ultracentrifugation identified one oestrogen-binding species of 7.1S. The receptors had a relatively high affinity for diethylstilboestrol (DES) but did not bind to a monoclonal antibody specific for the classical oestrogen receptor, suggesting that oestrogen receptors in macrophages could be of a different type.
Animals↗
Aflatoxin monoclonals: academic development to commercial production.
A monoclonal antibody (mAb) has been produced to aflatoxin B1 (AF B1) after successful immunization of mice and fusion of sensitized spleen cells with myeloma cancer cells. The mice were immunized with AF B1-oxime-protein conjugate. Positive mAbs were screened using an indirect ELISA specific for AF B1. The selected mAb was then developed in direct competitive ELISA and immunoaffinity column chromatography methods for aflatoxin detection in foods and feeds. Both assays are rapid, sensitive, specific and require only the minimum of sample preparation. Both immunological assays have now been commercialized and are produced in convenient ready-made kit formats.
Aflatoxin B1↗
Production and characterization of monoclonal antibodies with therapeutic potential against Shiga toxin.
Four monoclonal antibodies (T2D1, T3B1, T7B2 and T4C4) were produced and characterized against Sh. dysenteriae type 1. These monoclonal antibodies (McAbs) were shown to be directed against the same or adjacent determinants on the A-subunit of the Shiga toxin. All the anti-Shiga toxin McAbs are IgG1 (kappa) antibodies and have the capacity to neutralize the cytotoxic and neurotoxic effects of the Shiga toxin: the data strongly suggest that both of the activities, associated with the toxin, are due to the same molecule. In addition, the McAbs were found to be highly protective, at low dose, when administered therapeutically to lethally-treated animals.
Animals↗
The distribution of pregnancy-associated prostaglandin synthetase inhibitor in the human placenta.
The distribution of pregnancy-associated prostaglandin synthetase inhibitor (PAPSI) has been studied in 181 human placentae and early products of conception using a peroxidase-antiperoxidase (PAP) immunohistological method. PAPSI was detected in amniotic epithelium throughout all stages of gestation. Extravillous trophoblast was PAPSI-positive throughout gestation. Villous trophoblast was PAPSI-positive in the first 12 weeks of gestation, when PAPSI was localized to syncytiotrophoblast but not to cytotrophoblast. Villous syncytio- and cytotrophoblast were both PAPSI-negative from 12 weeks to term. Fetal and maternal polymorphs contained PAPSI at all stages of gestation, as did villous Hofbauer cells. The significance of these findings is discussed in relation to putative functions of PAPSI, particularly the maintenance of pregnancy and control of onset of parturition.
Amnion↗
Monoclonal antibody technology for mycotoxins.
Specific monoclonal antibodies (MABs) against aflatoxins, ochratoxin A, zearalenone, diacetoxyscirpenol and T-2 toxin have been prepared in various laboratories by the application of hybridoma technology to mycotoxins. These antibodies can be selected for sensitivity, reduced cross-reactivity, reliability and ease of production. When a suitable antibody is chosen it can then be used in a rapid immunological method such as an enzyme-linked or radio-immunoassay or immunoaffinity chromatography system. These assays have a lower limit of mycotoxin detection in the ng/ml range and have been applied to the determination of mycotoxins in samples such as maize, peanuts, peanut butter, milk and porcine kidneys. Using these immunoassay techniques, sample preparation has generally been simplified to a matter of solvent extraction of mycotoxins from the sample followed by dilution; under these conditions, levels of 1-5ug of mycotoxins/kg of sample can be found. The application and advantages of MABs to mycotoxins and the use of these antibodies in various assay techniques is discussed.
Journal Article↗
Cytokines regulate the ability of human LAK-cells to kill human tumour cells in vitro.
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Biological Factors↗
Ability of alpha (but not beta) form interleukin-1 to support DNA synthesis in human tonsillar B cells.
The ability of the two forms of recombinant human interleukin-1 (alpha and beta) to support DNA synthesis in human tonsillar B cells was assessed. The results suggested that in two out of three cases the alpha form was able to support DNA synthesis when the beta form was not. These results support the hypothesis that each form of human interleukin-1 has a different role in supporting the growth of human B cells.
B-Lymphocytes↗
Production and characterization of monoclonal antibodies with diagnostic potential against Shigella flexneri.
Highly specific monoclonal antibodies (McAbs), 1aM3, 2aM1 and 2bM2 were produced and characterized against Sh. flexneri 1a, 2a and 2b respectively. IaM3 is an IgG3 (lambda) type antibody reactive against whole bacteria or the lipopolysaccharide (LPS) only; 2aM1 is an IgG1 (kappa) type antibody which reacts with the polysaccharide component of LPS; 2bM2 is an IgG3 (lambda) type antibody which binds with both the polysaccharide and protein/peptide components of the LPS. The results indicate that specific McAbs with diagnostic potential can be produced using acetone-killed and dried cells as antigen. Ascitic fluid produced in mice using the anti-Sh. flexneri hybridomas was found not to contain higher titres of McAbs against the bacteria. A "nutritionally-deprived" medium was, therefore, constructed which produced greater than five times the concentration of the McAbs than that could be obtained using normal culture fluid.
Animals↗
The therapeutic effects of dietary fatty acid supplementation in the autoimmune disease of the MRL-mp-lpr/lpr mouse.
The effect of dietary fatty acids on the spontaneous autoimmune disease systemic lupus erythematosus of the MRL-mp-lpr/lpr mouse was investigated after onset of disease. Parameters monitored included auto-antibody levels (by ELISA), proteinuria, body weights, clinical appearance and survival. The preliminary study (using five mice per group) showed that dietary restriction improved survival (P less than 0.001) per se, and further that all mice receiving the fish oil diet benefited considerably (P less than 0.005), whilst males on the fish oil/evening primrose oil diet also lived longer than expected (P less than 0.005).
Animals↗
Oestrogen and human T lymphocytes: presence of specific receptors in the T-suppressor/cytotoxic subset.
Human spleen cells were investigated for specific oestrogen binding using oestradiol-17 beta. High affinity, low capacity binding was observed (Kd = 2.5 X 10(-10) M) and the characteristics of the oestrogen receptor identified were typical of this type of species. T lymphocyte subpopulations were prepared by negative selection by means of the monoclonal antibodies Leu 2a and 3a. Oestrogen receptors were only found in T cells of the suppressor/cytotoxic (CD8-positive) subset while helper/inducer lymphocytes (CD4-positive) showed no significant steroid binding by cytosol and nuclear assays. These results are supported by data from experiments into the effects of oestradiol-17 beta on immunoglobulin secretion, where it was apparent that only the suppressor/cytotoxic T-cell subpopulation was responsive to the presence of the steroid.
Adult↗
The maternal immune response to a new human trophoblast antigen.
The trophoblast membrane of the human placenta constitutes the effective interface between blood borne cells of the maternal immune system and foetal tissue. Therefore antigens expressed on this membrane are ideally located to induce an immune response. We have previously described a trophoblast antigen TA which induces a humoral response. In this study the leucocyte migration inhibition assay was employed to assess the cellular response of pregnant women to TA. Leucocytes from primigravidae and multigravidae responded to TA while controls did not. Addition of autologous pregnancy sera abrogated responses to TA but did not affect responses to BCG. We propose that pregnancy sera contains a blocking factor which contributes to the survival of the foetal allograft by suppressing a potentially hostile maternal immune response directed against TA expressed on the trophoblast membrane.
Antigen-Antibody Complex↗
Immunoscintigraphy of human ovarian cancer xenografts using a radiolabelled monoclonal antibody to human pregnancy serum-derived immune complexes.
The in vivo imaging of xenografted human ovarian cancer in nude mice with a specific and control radiolabelled monoclonal antibody (MoAb) is described. The specific MoAb was previously raised by immunizing mice with immune complexes derived from late human pregnancy serum. In the first group of mice the specific MoAb 131I-5E3 F(ab')2 was injected, while a second group received equivalent amounts of a control MoAb 131I-UJ13A F(ab')2. The mice were imaged at various times up to a maximum of 2 weeks using a gamma camera, and the tumour to non-tumour (T/NT) ratio was recorded for each group. The T/NT ratio rose to 2.02 in the specific group, while the corresponding ratio in the control group was 0.70. In addition, the count rate in the tumour and non-tumour regions was determined on each imaging occasion. Biological half-lives of the divalent fragments of 5E3 and UJ13A in the tumour were 7.53 days and 0.62 days, respectively. Following sacrifice, the tumours were excised and counted relative to the rest of the animal, and the T/NT ratio was calculated. In vitro results were in direct agreement with those recorded in vivo using the gamma camera. From the results it would appear that the divalent fragment of 5E3, which has been raised to immune complexes derived from late human pregnancy serum, is specific for human ovarian tumour xenografts in the nude mouse model.
Animals↗
Responses of human B-cells to recombinant lymphokines.
The effects of recombinant or purified cytokines on the growth and differentiation of human B-cells from a variety of sources were evaluated. The results suggest that IL-1, BCGF and BSF-2 have either "growth-factor" or "differentiation-factor" activity and that only IL-2 has both these functions. In addition, evidence is presented that the two forms of human IL-1 affect B-cell growth differently. Finally, the separation of human normal and leukaemic B-cells into subsets defined by their buoyant cell density, is described.
B-Lymphocytes↗
Immunoscintigraphy of metastases with radiolabelled human antibodies.
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Adenocarcinoma↗