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Biomedical subjects

D M Pinson

Publications and source records attributed to D M Pinson.

29 records · Page 2Linked to original sources
PubMed1992

Characterization and use of monoclonal and polyclonal antibodies against the mouse interferon-gamma receptor.

To facilitate investigation of its physical and functional properties, 11 monoclonal antibodies (mAbs) and a goat polyclonal IgG specific for the mouse interferon- (IFN-gamma) receptor were characterized and their potential uses studied. Eight of the mAbs interacted with epitopes on the extracellular domain of the receptor, two interacted with epitopes on the intracellular domain, and one interacted with an epitope that could not be localized definitively to either region. Of the 11 mAbs, the majority (8) were IgGs, 2 were IgMs, and 1 was an IgA. Relative avidities of the seven that could be determined ranged from 333 to 0.002 microM-1. Both the polyclonal goat IgG and mAb GR-20 (the latter specific for an epitope in the binding site for IFN-gamma) blocked binding of the ligand and, as expected, prevented induction by IFN-gamma of priming of macrophages for tumor cell killing. None of the other mAbs had an effect despite the fact that GR-22 partially (greater than 50%) blocked binding of IFN-gamma. Neither the polyclonal IgG nor any of the mAbs had an agonist effect. The relative usefulness of the antibodies for immunoprecipitation, immunoblotting, immunoassay, and cell staining with and without prior fixation is described. The results of immunocytochemical staining directly confirmed that the majority of immunologically reactive receptor protein expressed by cells is intracellular. To facilitate use by other investigators, the hybridomas that produce these mAbs will be offered to the American Type Culture Collection.

Animals↗
PubMed1991

Activation-associated marker proteins: peptide mapping and their expression in macrophage cell lines.

The activation-associated markers, p47b and p71/73, have been recognized as minor proteins in peritoneal and bone marrow culture-derived macrophages activated for tumor cell killing. Proteins with identical characteristics of migration on 2-dimensional gels and comparable Cleveland peptide maps are described here in macrophage cell lines that could be activated for tumor cell killing (J774A.1, RAW 264, UNC-2). Macrophage cell lines that could not be activated (P388D1 and PU5-1.8) did not express the markers. The expression of these markers in activatable macrophage cell lines strengthens their association with the activation process and provides a bulk source of the proteins for purification studies.

Animals↗
PubMed1989

A monoclonal antibody against the ligand binding site of the receptor for mouse interferon-gamma.

A rat monoclonal IgG2a antibody, GR-20, has been produced against the receptor for mouse interferon-gamma (MuIFN-gamma). Comparison of competitive binding studies performed with either 125I-labeled GR-20 or recombinant (r) MuIFN-gamma, as well as a variety of other studies, suggested that the epitope recognized by the monoclonal antibody (mAb) is in the domain of the receptor that binds ligand. The binding of GR-20 to cells of the monomyelocytic line WEHI-3 was of high affinity (1-2 nM). Approximately 20,000 binding sites were found per cell, a value that is in close agreement with the number of MuIFN-gamma receptors quantified on cells of the same type by ligand binding studies. The mAb also bound to a variety of other mouse cells, suggesting that the same epitope is shared by receptors for MuIFN-gamma, regardless of cell type. The epitope was not detected on two human cell types that were tested, while cells of a rat cell line shown to be minimally responsive to rMuIFN-gamma gave equivocal binding results when they were interacted with GR-20. Binding of the mAb to the receptor did not mimic the effects of ligand. In fact, the opposite was true: binding blocked the induction of three biological effects of MuIFN-gamma, including priming of macrophages for tumor cell killing, upregulation of the expression of class II major histocompatibility antigens (Ia) on the same cell type, and induction of antiviral activity in L cells. Following intravenous injection, initial removal of GR-20 was precipitous, followed after 1 h by a phase which was more gradual, resulting in 5-10% of biologically active mAb remaining in the circulation after 24 h. Such retention should make this mAb useful in a variety of studies in vivo.

Animals↗
PubMed1988

Purification and partial characterization of a receptor protein for mouse interferon gamma.

A receptor protein for mouse interferon gamma has been purified from solubilized plasma membranes of the mouse monomyelocytic cell line WEHI-3. Sequential wheat germ agglutinin and ligand affinity chromatography of membranes extracted with octyl beta-D-glucopyranoside resulted in at least a 680-fold purification of the receptor, as measured by precipitating it in association with liposomes composed of phosphatidylcholine. The purified receptor bound 125I-labeled recombinant mouse interferon gamma (rMuIFN-gamma) with a Kd of 10 nM, a value comparable to that obtained with isolated membranes (3.5 nM). PAGE analysis of radiolabeled (with either 35S or 125I) receptor preparations consistently revealed a major band of 95 kDa. This species was degraded with time to smaller fragments, principally one of 60 +/- 5 kDa. Treatment with peptide:N-glycosidase F reduced the apparent molecular masses of the proteins in the 95- and 60-kDa regions by 15-20 kDa each. GR-20, a monoclonal antibody against the receptor, completely inhibited specific binding of 125I-labeled rMuIFN-gamma to WEHI-3 cells, blocked the induction of priming by rMuIFN-gamma of macrophage-mediated tumor cell killing, removed binding activity for 125I-labeled rMuIFN-gamma from solubilized membranes, and immunoprecipitated a single 95-kDa protein from the extract of surface labeled (125I) WEHI-3 cells. Cross-linking of 125I-labeled rMuIFN-gamma to its receptor yielded a complex of 125 +/- 5 kDa, consistent with the binding of the dimeric form of mouse interferon gamma (32 kDa) to a membrane protein of 95 kDa. These data suggest that the receptor for mouse interferon gamma (or a ligand-binding subunit thereof) is a glycoprotein of 95 kDa.

Animals↗
PubMed1988

Promotion of Mycoplasma pulmonis growth in rat tracheal organ cultures by ammonium chloride.

During exacerbation of respiratory mycoplasmosis in rats by environmental ammonia, numbers of Mycoplasma pulmonis organisms in the respiratory tract are increased. To test whether or not exposure of respiratory epithelium to ammonia in vitro promotes growth of the organism, rat tracheal organ cultures were treated with 50 mM ammonium chloride, inoculated with M. pulmonis, and quantitatively cultured. After 48 hours, treated tracheas harbored almost 10 times more M. pulmonis colony-forming units than control tracheas. Cellular lesions in the epithelium of treated tracheas resembled those in the nasal passages of rats exposed to gaseous ammonia. To determine whether or not growth-modifying factors were released from tracheal epithelium exposed to ammonium chloride, M. pulmonis growth was assessed in medium collected from ammonium chloride-treated and control tracheas. Growth in medium from treated tracheas was greater than that in medium from untreated tracheas.

Ammonium Chloride↗
PubMed1987

Neurotoxicosis associated with the use of hexachlorophene in a cat.

Two weeks after daily topical application of hexachlorophene, a 4-week-old female kitten developed cardiovascular collapse, corneal ulcers, trembling, lethargy, and weakness. The kitten was euthanatized. At necropsy, the tissues appeared macroscopically normal; however, microscopic examination of tissue specimens indicated status spongiosis, astrocytosis, and microgliosis of the cerebral and cerebellar white matter and corticospinal tracts. Neuronal cell bodies forming the affected white matter were intact, indicating that demyelination may have been the cause of the lesions. The neurologic lesions were considered compatible with those of hexachlorophene-induced toxicosis.

Animals↗
PubMed1986

Evaluation by scoring and computerized morphometry of lesions of early Mycoplasma pulmonis infection and ammonia exposure in F344/N rats.

To evaluate lesions of ammonia exposure and Mycoplasma pulmonis infection in gnotobiotic F344/N rats, groups of rats were inoculated with M. pulmonis, exposed to 76 micrograms/liter (100 parts per million) ammonia, or both, or served as controls. Six rats from each group were killed 3, 5, 7, and 9 days after inoculation and their respiratory organs prepared for histologic examination. Lesions were assessed by subjective scoring and computerized morphometry, and results obtained by the two methods were compared to assess agreement of results. Lesions were limited to the nasal passages. Ammonia exposure resulted in hyperplastic and degenerative changes in the anterior nasal epithelium. Lesions of mycoplasmosis were more severe in ammonia-exposed than unexposed rats, but qualitative differences in lesions were not apparent. Results of the two methods agreed in assessment of submucosal inflammatory cell accumulation. Epithelial lesions were difficult to evaluate by both methods in infected, ammonia-exposed rats. In evaluation of lesions of ammonia exposure alone, agreement was adequate. Both methods indicated that exudates were significantly greater in ammonia-exposed infected rats than in non-exposed infected rats. Thus, scoring and morphometry provided similar assessments of differences in lesion severity among the treatment groups.

Ammonia↗
PubMedDate not supplied

Early activation of PBMC and appearance of antiviral CD8+ cells influence the prognosis of SIV-induced disease in rhesus macaques.

We studied 15 macaques inoculated with SIV and identified three phases of infection. Phase 1 was characterized by activated lymphocytes in blood and infected cells in the CSF. In phase 2, activated cells were not detected but virus was recovered from mitogen-stimulated PBMC, while in phase 3, virus was recovered from mitogen-stimulated PBMC only after depletion of CD8+ lymphocytes, indicating effective control of the virus in peripheral blood. Early development of phase 3 status correlated with a longer period of clinical normalcy.

Animals↗
PubMedDate not supplied

Chimeric SHIV that causes CD4+ T cell loss and AIDS in rhesus macaques.

By animal to animal passage in rhesus and pig-tailed macaques, we developed a rhesus model of HIV-1 disease in humans. Rhesus macaques infected with a cell-free stock of SHIVKU-2 developed CD4+ T cell loss, primary lentiviral encephalitis and pneumonia, and AIDS. Six of nine rhesus macaques died within eight months post-inoculation, while the remaining three are at five, five, and eight months post-inoculation, respectively. Animals infected by either mucosal or parenteral routes of infection had a similar course of infection.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Immunomodulatory effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin tested by the popliteal lymph node assay.

Drugs and other chemicals that have the potential to induce or exacerbate systemic autoimmune diseases in humans are of great concern. The aim of this study was to examine the immune-disregulating potential of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by using the popliteal lymph node (PLN) assay. Chlorpromazine (CPZ) was used as a reference compound for 2 reasons: (a) CPZ is known to elicit a positive response in this assay, and (b) CPZ is a structural analogue of TCDD. Male Sprague-Dawley rats were injected subcutaneously with either TCDD or CPZ into the right hind footpad, whereas vehicle alone was injected into the contralateral footpad. Control rats were injected with vehicle in both hind footpads. Animals were sacrificed on day 7, and their PLNs were removed, weighed, and immersed in 10% formalin. The PLN weight index (the weight ratio of right PLN over left PLN) was significantly higher in both CPZ- and TCDD-treated rats than in controls. Histological examinations of PLNs in the CPZ- and TCDD-treated rats revealed similar morphological changes in both groups (e.g., mild follicular hyperplasia with no evidence of an acute inflammatory response). These results indicate that TCDD has the potential to induce or exacerbate autoimmune-like reactions. Results also suggest that drugs may be useful surrogates to study the mechanism of toxicity of environmental chemicals that cannot be administered to humans.

Adjuvants, Immunologic↗