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Biomedical subjects

K James

Publications and source records attributed to K James.

At least 199 records · Page 11Linked to original sources
PubMed1986

Identifying leucocytes and leucocyte subpopulations in semen using monoclonal antibody probes.

An indirect immunoperoxidase technique employing specific monoclonal antibodies has been used to identify leucocyte subpopulations in cytocentrifuge smears of washed human ejaculate. Cells reacting with the pan antihuman leucocyte monoclonal antibody (HLe-1) were demonstrated in 63/67 specimens from subfertile patients with a mean count of 14.5 +/- 17.1 leucocytes per HPF (X 320). Cells with similar reactivity were observed in all specimens examined from 10 fertile men with a mean count of 41.6 +/- 26.3 leucocytes per HPF (X 320). Leu-T4+ cells (T-lymphocytes) were demonstrated in only 13/63 of the subfertile group with a mean count of 4.46 +/- 3.3 T-lymphocytes per HPF (X 320). Studies with the anti-leu 2a antibody revealed that these leu-4+ cells were mainly of the suppressor/cytotoxic phenotype. In contrast, no leu-4+ cells were detected in the control group. No leu-12+ cells (B-lymphocytes) were detected in any of the 80 specimens examined.

Antibodies, Monoclonal↗
PubMed1986

Autoantibodies to Alzheimer and normal brain structures from virus-transformed lymphocytes.

B-Lymphocytes from two patients with Alzheimer's disease and one healthy subject were transformed into lymphoblastoid cells by exposure to Epstein-Barr virus. In culture, more than 50% of these cells secreted sufficient IgM or IgG antibody (mainly IgM) to allow immunohistochemical screening against cryostat sections of normal and Alzheimer temporal cortex. More than 30% of the IgM antibodies from each subject recognised brain components, namely: neurons, astrocytes, nuclei, nucleoli, and Alzheimer plaques and neurofibrillary tangles. This methodology represents a major addition to the procedures currently available for the generation of antibodies towards normal and pathological structures in human brain.

Alzheimer Disease↗
PubMed1986

Monoclonal antibodies to human hypoglossal nucleus which stain neurons and astrocytes in normal brains and brains from cases of Alzheimer-type dementia.

Monoclonal antibodies were raised to membranes of hypoglossal nuclei from normal human post-mortem brain. Two of these clones were recloned to yield antibodies ES.18 and ES.19. Antibody ES.18 stained some, but not all, neuronal perikarya in the medulla oblongata and other brain areas. Neurons stained by this antibody did not have a common neurotransmitter or physiological function, although they tended to be large. Perikarya in the basal forebrain nucleus from a case of Alzheimer-type dementia were stained much more intensely by ES.18 than were these perikarya in a control brain. Antibody ES.19 did not stain neuronal perikarya but stained glial fibrillary acidic protein-positive processes below the pia, in the subependymal layer and in the molecular layer of the cerebellum of control and Alzheimer brains. This antibody also stained the numerous glial fibrillary acidic protein-positive astrocytes in Alzheimer cerebral cortex, but did not stain glial fibrillary acidic protein-positive astrocytes in the white matter of brains from controls or cases of Alzheimer-type dementia. The staining pattern of ES.19 suggests that fibrous astrocytes in Alzheimer cerebral cortex are antigenically different from fibrous astrocytes in white matter.

Alzheimer Disease↗
PubMed1986

Characterisation of mouse monoclonal antibodies produced by immunisation with a single serotype component of a polyvalent Pseudomonas aeruginosa vaccine.

Mouse monoclonal antibodies raised by immunisation with a protective antigen extract from Pseudomonas aeruginosa serotype 1 varied in immunoglobulin isotype, in passive protective properties against infection by homologous P. aeruginosa serotype 1, and in cross-reactions in ELISA against antigen preparations from 15 other P. aeruginosa serotypes. All monoclonal antibodies with specificity in ELISA for the immunising antigen gave some degree of protection to mice against lethal infection by the homologous P. aeruginosa serotype. The IgG antibodies were more protective than the IgM antibodies.

Animals↗
PubMed1986

Isotype responses of mice to tetanus-toxoid preparations.

The development of anti-tetanus antibodies in CBA/Ca and Balb/c mice immunised with two tetanus-toxoid preparations has been investigated by sensitive enzyme-linked immunoassays. These studies revealed the presence in both strains of mice of naturally occurring antibodies to tetanus toxoid. These were of the IgM, IgA and, to a lesser extent, the IgG3 isotypes. Differences in the responses of mice to the two toxoid preparations were noted; the purer preparation elicited a more rapid and pronounced response. Both strains of mice exhibited similar isotype responses.

Animals↗
PubMed1986

Leucocytes in the ejaculate from fertile and infertile men.

The presence of leucocytes and their subpopulations was studied in the ejaculate from 69 men with an infertile marriage and 12 fertile men. Monoclonal antibodies specific for human leucocytes were used in an immunoperoxidase technique. In addition to the standard sperm analysis, each specimen was also tested for sperm antibodies, aerobic and anaerobic microorganisms, Ureaplasma urealyticum and Chlamydia trachomatis. Leucocytes were found in large numbers in the fertile men compared with the patients. Lymphocytes were found in 20% of the patients. Micro-organisms were cultured from a similar proportion of both groups. We found no correlation between leucocyte counts, sperm density and motility, sperm antibodies and growth of micro-organisms. Our results cast doubt on the conventional criteria of subclinical genital tract infection, namely positive culture and excess leucocyte counts.

Ejaculation↗
PubMed1986

Immunohistochemical identification of lymphocyte subsets and macrophages in normal human urothelium using monoclonal antibodies.

Monoclonal antibodies were used to examine the pattern of distribution of lymphocyte subpopulations and macrophages in normal human urothelium. T lymphocytes (T11-positive cells) were demonstrated within the epithelium and within the lamina propria of both the ureter and the urinary bladder. Suppressor/cytotoxic T cells (T8-positive cells) predominated, with the average ratio of suppressor/cytotoxic T cells to the helper/inducer T cells being approximately 8.9 in the epithelium and 1.5 in the lamina propria. Leu M3+ cells (monocytes/macrophages) were detected in both epithelium and lamina propria. The character and distribution of these immunocompetent cells within the urothelium suggest a protective function, especially against infection and in tumour surveillance.

Antibodies, Monoclonal↗
PubMed1985

Fluoresceinated alpha 2-macroglobulin as a probe for studying macrophages.

The potential value of fluorescein-conjugated human alpha 2-macroglobulin as a probe for studying macrophages in murine peritoneal exudate and spleen cell suspensions has been investigated using a fluorescence-activated cell sorter. These studies revealed that the number of alpha 2-macroglobulin-positive cells in the mixtures examined correlated closely with their macrophage content as determined morphologically. Furthermore cells separated on the FACS on the basis of their strong alpha 2-macroglobulin binding exhibited macrophage morphology and expressed Fc receptors on their surface. Conversely the alpha 2-macroglobulin-negative population contained few macrophages or Fc rosette-forming cells. Extensive blocking and comparative binding studies with a number of purified human alpha 2-macroglobulin preparations and derivatives thereof, and a variety of purified proteins, confirmed that the binding of fluorescein-conjugated alpha 2-macroglobulin to peritoneal exudate cells was specific. Furthermore the binding occurs in a highly reproducible manner. These observations suggest that fluorescein-conjugated alpha 2-macroglobulin in conjugation with flow cytometry is a sensitive and reliable method for both identifying and isolating subpopulations of macrophages.

Animals↗
PubMed1985

Enhancement of factor VIII-von Willebrand factor ristocetin cofactor activity by monoclonal antibodies.

Five monoclonal antibodies to human von Willebrand factor were selected for characterization from 18 produced in murine hybridomas. All showed a high and specific affinity for human von Willebrand factor (vWf) but exhibited little if any cross-reaction with sera from other species. The antibodies defined four epitopes on vWf, none of which were involved in platelet binding. Binding of two distinct antibodies at one of these epitopes was associated with enhancement of the rate of vWf-dependent platelet agglutination in the presence of ristocetin. This effect was more noticeable when cryosupernatant plasma was used in place of normal plasma as the source of vWf, and was not explicable simply in terms of antibody-induced cross-linking of vWf.

Animals↗
PubMed1985

Characterisation of epitopes on human tissue plasminogen activator recognised by a group of monoclonal antibodies.

Seven mouse monoclonal antibodies have been produced against human melanoma tissue plasminogen activator (t-PA). They were specifically bound to 125I t-PA but not 125I urokinase (u-PA) and inhibited t-PA, but not u-PA, activity in plasminogen-rich 125I fibrin wells. Three of the antibodies directly inhibited the amidolytic activity of t-PA and the two most effective also bound near the active site histidine residue as determined by competition experiments using active site blocking agents. Several antibodies interfered with the fibrin binding properties of t-PA. One antibody neither interacted with the active site nor inhibited fibrin binding but still effectively quenched t-PA activity in fibrin wells suggesting that it masks another region of the molecule necessary for effective biological activity.

Animals↗
PubMed1985

Human seminal plasma is a potent inhibitor of natural killer cell activity in vitro.

The effect of human seminal plasma on the natural killer (NK) activity of human peripheral blood leukocytes in vitro has been investigated. Small concentrations (as low as 0.01% v/v) of seminal plasma were found to inhibit the ability of human peripheral blood leukocytes to lyse K562 target cells. These inhibitory effects were observed with seminal plasma donations from normal and infertile individuals, including those who had been vasectomised. The inhibition noted appeared to be independent of the presence of antisperm antibodies which could conceivably cross-react with NK cells. Furthermore, the factors responsible survived boiling for 15 min and could not be absorbed out with K562 target cells. These profound inhibitory effects might be relevant to malignancy of the urogenital tract and the defence against sexually transmitted disease.

Autoantibodies↗
PubMed1985

Lymphocyte sub-populations in the male genital tract.

A series of monoclonal antibodies that react with human lymphocyte subsets was used in an indirect immunoperoxidase technique to study representative blocks from normal human testis, epididymis, vas deferens, prostate and seminal vesicles. Biopsies of testis, epididymis and vas obtained during surgical procedures directed at the investigation and treatment of infertile males were also studied. In all normal tissues, apart from the peripheral testis where no lymphocytes were identified, T lymphocytes were the predominant cell type (Leu 4+). These lymphocytes were largely of the suppressor/cytotoxic phenotype (Leu 2a+) and were more abundant in between the epithelial cells in the rete testis, epididymis, vas deferens, seminal vesicles and prostatic acini. Cells of the helper/inducer phenotype (Leu 3a+) were identified mainly within the interstitium of the epididymis and the prostate. B-lymphocytes (Leu 12+) were few in number and were mainly in the stroma of the prostate. In each organ the ratio of the T-cell subsets was determined and changes in this ratio were observed in epididymal and vasal biopsies from some infertile males. Finally, in testis biopsies from infertile men, suppressor/cytotoxic T-cells were demonstrated between the germinal epithelium and the fibrous tunica of the seminiferous tubules and as focal aggregates in the interstitium.

Antibodies, Monoclonal↗
PubMed1984

Monoclonal antibodies directed against human alpha-thrombin and the thrombin-antithrombin III complex.

Human alpha-thrombin was poorly immunogenic in Balb/c mice. Nevertheless, following fusion of spleen cells from a responding mouse with NS-1 cells, 8 mouse monoclonal antibodies against alpha-thrombin were isolated, and 6 were characterised. Five of these were isotype IgG2a, and one was IgG1. One, EST 1, bound thrombin only minimally, and was directed against a neoantigen on the thrombin-ATIII (T-AT) complex. This antibody also recognised a site on prothrombin, though with much lower affinity. Its binding was markedly temperature-dependent, indicating a requirement for molecular mobility. A second antibody, EST 4, would not bind the T-AT complex. It inhibited both the clotting and amidase activities of thrombin, and modification of the active site histidine, but not the active site serine, reduced the affinity constant of binding to EST 4. This antibody appears to be directed against an epitope in the vicinity of the enzyme active site. The epitopes for EST 1 and EST 4 were both remote from those of the other monoclonal antibodies, EST 2, 6, 7 and 8. These four competed with each other for binding to thrombin, and all inhibited clotting but not amidase activity. Thrombin binding was not affected by modification of the active site, though formation of the T-AT complex reduced the affinity of binding to EST 6 and EST 8. These monoclonals recognise epitopes in the region of the fibrinogen binding site.

Animals↗
PubMed1984

The effect of anaesthesia and surgery for benign disease of the upper urinary tract on circulating leucocyte subpopulations identified with monoclonal antibodies.

Circulating lymphocyte subpopulations were monitored, using monoclonal antibodies and flow cytometry, in six patients undergoing surgery for benign disease of the upper urinary tract. A significant decrease in the total number of circulating lymphocytes was observed. This could be attributed to a significant decrease of T cells of both major subsets--the so-called T "helper" (Th) and T "suppressor/cytotoxic" (Ts) subpopulations. When the results of the T cell subsets were expressed as a ration (leu-3a+/leu-2a+, T "helper/suppressor") no significant change was noted. In contrast neither B cells nor natural killer (NK) and antibody dependent killer (K) cells were significantly affected. This selective loss of T cells from the circulation may be relevant to post operative infection and should be considered in the course of immunological monitoring.

Adolescent↗
PubMed1984

Asbestos-activated peritoneal macrophages release a factor(s) which inhibits lymphocyte mitogenesis.

Intraperitoneal asbestos injection in mice has previously been reported to elicit an activated macrophage population. In the present study supernatants from such macrophages were tested for their effect on thymocyte mitogenesis in response to concanavalin A; control supernatants were obtained from saline- and latex-elicited macrophages. Supernatants from asbestos-elicited macrophages were significantly inhibitory to thymocyte mitogenesis while saline- and latex-elicited macrophages did not release significant amounts of such activity. Asbestos-activated macrophage supernatants were inhibitory in a dose-dependent way and the activity was not secreted by macrophages from mice which had received asbestos in the long term. The inhibitory activity was partially dialysable. Supernatants prepared by treating macrophages in vitro with a lethal dose of asbestos were not inhibitory suggesting that the inhibitory activity in the supernatants of asbestos-activated macrophages did not leak from dead or dying cells. The asbestos macrophage supernatant was also significantly inhibitory to mature T-cell-enriched spleen cells but had no effect on fibroblasts, suggesting that the inhibitory effect could be lymphoid cell specific.

Animals↗