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A C Cunningham

Publications and source records attributed to A C Cunningham.

26 records · Page 2Linked to original sources
PubMed1990

Reversal of colchicine-induced mitotic arrest in Chinese hamster cells with a colchicine-specific monoclonal antibody.

The ability of a high-affinity colchicine-binding monoclonal antibody to reverse the effects of colchicine on Chinese hamster ovary cells was investigated. Using flow cytometry, a complete mitotic blockade was demonstrated after 16 hours with 2.5 x 10(-7) mol/l (molar) colchicine. Colchicine-induced changes were reversible when equimolar antibody was added simultaneously with or up to 6 hours after colchicine. With further delay in addition of antibody, a progressive irreversible increase in mitotic blockade and increase in mean cell size was observed. Prolonged colchicine exposure, without antibody reversal, led to polyploidy and structural chromosome breakage. Early antibody reversal restored cells to the diploid state, whereas delayed reversal resulted in a time-dependent increase in polyploidy. Colchicine-induced polyploidy and chromosomal aberrations may be the basis for both colchicine toxicity and the time-dependent increase in irreversibility of colchicine effects.

Animals↗
PubMed1989

Effects of dazmegrel, piroxicam and cyclophosphamide on the NZB/W model of SLE.

To investigate the potential importance of prostaglandins and thromboxane in systemic lupus erythematosus (SLE), the effects of a nonsteroidal antiinflammatory drug (piroxicam) and a thromboxane synthetase inhibitor (dazmegrel) were examined on survival, proteinuria, food consumption, body weight, and peripheral lymphocyte subset distribution in the NZB/W model of autoimmune lupus disease. The effect of an immunosuppressant (cyclophosphamide) known to be effective in the treatment of murine lupus on these parameters was also examined. Cyclophosphamide at 25 mg/kg ip weekly prolonged survival, inhibited proteinuria and prevented the characteristic decline in peripheral T cells and the relative increase in B cells seen in NZB/W lupus disease while having no apparent effect on body weight or food consumption. Neither dazmegrel at 50 or 200 mg/kg/day in the diet nor piroxicam at 2 mg/kg/day in the diet had any significant effects on these parameters.

Animals↗
PubMed1989

Specific, high affinity colchicine binding monoclonal antibodies: development and characterization of the antibodies.

Nine colchicine specific monoclonal antibodies have been developed by immunizing BALB/c mice with a colchicine-keyhole limpet hemocyanin (Col-KLH) conjugate prepared using a bishydroxysuccinimide coupling reagent. Of four immunization procedures examined, intraperitoneal injection of the antigen attached to acid treated E. coli resulted in the maximum antigen specific antibody titers. A colchicine bovine serum albumin (Col-BSA) conjugate, prepared using a water soluble carbodiimide coupling technique, formed the basis of an enzyme linked immunosorbent assay used for screening hybridomas for colchicine specific antibody secretion and for determining the relative affinity and specificity profile of the monoclonal antibodies. All antibodies demonstrated high affinity, saturable binding to colchicine and low cross-reactivity with a panel of compounds structurally related to colchicine. The IC50 for the highest affinity antibody, C44, was 3.6 +/- 0.84 nM colchicine in the competitive enzyme immunoassay. The affinity of this antibody determined from Scatchard analysis of antibody binding to tritiated colchicine was 0.66 +/- 0.11 nM. Antibody C44 has the level of specificity and affinity suitable for a sensitive and selective immunoassay of colchicine for monitoring therapeutic drug levels. In addition, this antibody provides a specific pharmacologic antagonist for studies of colchicine's therapeutic mechanism and has the potential to reverse colchicine toxicity.

Animals↗
PubMed1988

A pharmacologic study of the relationship between lymphocyte function and surface antigen expression.

The relationship between functional activity and distribution of lymphocyte surface markers has not been clearly defined. We have examined the relationship between cell surface markers and function under the influence of immunosuppressant therapy. We found that after immunization with EL4 cells, the development of the immune response in the BALB/c mouse was accompanied by a decrease in spleen cells which stained brightly with fluorescein-labeled monoclonal anti-Thy 1 and an increase in cells which stained with rabbit anti-mouse Ig as measured on the FACS. Low doses of azathioprine and cyclophosphamide, which affect functional activity of the cells, do not alter cell surface markers. However, at higher doses of the drugs normalization of immunization-induced marker changes were observed, and the Thy 1+ and Ig+ surface markers were maintained at levels seen in non-immunized mice. In spite of a nearly 3-fold increase in the total number of lymphocytes and an increase in the functional activity of cytotoxic T cells (Lyt 2+) after immunization, no alteration in the percentage of Lyt 2+T cells nor in the intensity of staining with FITC-labeled Lyt2 antibody was seen. Inhibition of the immune response with immunosuppressant also failed to change the Lyt2+-staining cell population. This study demonstrates that lymphocyte functional changes precede cell surface antigen changes, and that functional changes may occur without surface antigen changes. Thus cell surface markers are "late" indicators of functional changes.

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PubMed1983

The gene coding the human S11 surface antigens maps between the loci for HPRT and G6PD on the X-chromosome.

The human S11 surface antigens are expressed on fibroblasts and are coded by a gene on the X-chromosome. We have regionally mapped this gene by examining S11 expression on a panel of hybrid lines which had fragmented the X-chromosome either during chromosome-mediated gene transfer, or by interspecies translocation during hybrid cell expansion. using indirect immunofluorescence and the fluorescence-activated cell sorter (FACS), it was possible to isolate antigen-positive and -negative hybrid subpopulations for subsequent genetic analysis. The gene coding S11 could be localized to Xq27-28, between the loci for HPRT and G6PD where genes for the S10 and S12 antigens have been previously mapped. This work demonstrates the value of cell surface antigens and the FACS in somatic cell genetic analysis, and provides evidence for regional clustering of surface antigen loci on the human X-chromosome.

Animals↗
PubMed1982

Chromosomal location of a human alpha interferon gene family.

To determine the chromosomal location of the human alpha interferon genes, we scored a series of human/rodent somatic cell hybrids for the presence of DNA sequences hybridizing to an alpha 1 interferon DNA probe. The presence of human chromosome 9 in a hybrid correlated with the presence of a family of alpha interferon genes.

Animals↗
PubMedDate not supplied

An in vitro system to model pulmonary epithelial barrier dysfunction mediated by immune effector cells.

An assay of epithelial barrier function was developed to monitor immune-mediated changes in lung permeability that may be occurring during pulmonary allograft rejection and inflammatory lung diseases. Lung tissue was obtained from minipigs, digested with collagenase (1 mg/ml) overnight, and propagated in RPMI 1640 tissue culture medium. Cells with an epithelioid morphology were purified by differential detachment using trypsin-ethylenediaminetetraacetic acid and were characterized as epithelial by positive staining with an anti-cytokeratin monoclonal antibody. Monolayers of these epithelial cells were cultured on porous tissue culture inserts, and transmonolayer resistance values were measured. Transmonolayer resistance values reached a mean of 5487 +/- 2882 omega (mean +/- 95% confidence interval; n = 9) after 5 days in culture. These values indicated the presence of functional intercellular tight junctions between the cells. Addition of cytotoxic immune effector cells to the cultured monolayers caused a rapid reduction in the transmonolayer resistance values, whereas unstimulated splenocytes failed to produce this effect. Comparison of these results with those obtained in parallel experiments performed with standard isotopic cytotoxicity assays indicated the sensitivity of the transmonolayer resistance technique. The assay described in this report will enable in vitro modeling of epithelial permeability damage mediated by both activated lymphoid cells and their soluble products.

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