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J R Pink

Publications and source records attributed to J R Pink.

At least 55 records · Page 3Linked to original sources
PubMed1986

Functional antagonism between type I and type II interferons on human macrophages.

A three-day treatment with IFN-gamma enhanced up to 300% the capacity of human monocytes and macrophages to produce H2O2 during the respiratory burst. IFN-alpha or -beta (type I IFNs), which did not by themselves influence the burst, were found to antagonize the enhancing effect of IFN-gamma (type II IFN). The antagonism was concentration-dependent and required the presence of type I IFNs during the whole period of IFN-gamma pretreatment. These results suggest that the host defense function of mononuclear phagocytes may be controlled by the relative local concentrations of type I and type II IFNs.

Humans↗
PubMed1986

Avian B cell precursors: surface immunoglobulin expression is an early, possibly bursa-independent event.

The avian bursa of Fabricius contains about 1 X 10(4) discrete follicles, each of which is colonized by a small number of lymphoid progenitor cells during embryonic life. We have previously shown (J.R.L. Pink et al., Eur. J. Immunol. 1985. 15:617) that all, or almost all B cell progenitors in the bursae of 4-day-old chicks express cell surface IgM. In this report, we have analyzed the distribution of cell surface (s)IgM-1 allotypes within individual follicles of (M-1a/M-1b) allotype heterozygous birds. Although the majority of follicles contained a mixture of sIgM-1a+ and sIgM-1b+ cells, a significant proportion of isolated follicles contained exclusively sIgM-1a+ or sIgM-1b+ cells. Statistical analysis of the frequency of such "M-1a" and "M-1b" follicles demonstrated that the sIg+ B cells in the bursae of 4-8-week-old birds are derived from 2-4 allotypically committed precursor cells per follicle. Since we have previously shown that each bursal follicle is colonized by 2-5 pre-bursal stem cells, these cells must be committed to the eventual expression of one or other allotypic haplotype before they have undergone extensive proliferation within the bursa. In addition, we show that almost all B progenitor cells from the bursae of chicks which had been allotype suppressed as embryos were committed to synthesis of the nonsuppressed allotype, showing that this commitment was essentially complete at the time of suppression (i.e. before 19 days of incubation). Finally the bone marrow of 16-day embryos was used to reconstitute the bursal lymphocytes of cyclophosphamide-treated host embryos. Reconstitution was inhibited by anti-Ig antiserum indicating that most 16-day embryonic BM-derived bursal cell precursors also express sIgM. These results raise the possibility that expression of sIgM may be controlled by a "biological clock" rather than by any inductive capacity of the bursal microenvironment. Furthermore, these results provide further evidence that in normal birds a self-renewing sIg+ B cell population in the hatched chicken is the sole source of B cells in the adult.

Animals↗
PubMed1986

Chick embryonic erythrocyte antigen--tissues sharing expression.

There is an antigenic glycoprotein (Mr 48 kD) present on the surfaces of erythrocytes of embryonic and young chickens that cannot be detected on the circulating erythrocytes in adult birds. This antigen, generally defined by this differential expression, has been thought to be associated with the maturation of hematopoietic tissues. We now present evidence, based on the use of a monoclonal antibody, maEE1, and the characteristic pattern of this glycoprotein on two-dimensional (2D) gels, that this antigen, which we have named chickEE, is expressed in a number of other embryonic and adult tissues. Immunofluorescent labeling of cryosections and flow-cytometric analysis of cells labeled with maEE1 have revealed the presence of chickEE in the retina (present in all layers), in muscle tissues (present in the endomysium and within the vascular endothelium), in the liver (especially evident on the lateral surface of hepatocytes and within the sinusoids), on epithelia such as the gut and kidney tubule epithelium and within lymphoid organs (present on bursacytes, splenocytes, thymocytes and peripheral leukocytes, and again within the endothelium) of young and adult animals. The 2D gel patterns of chickEE derived from embryonic tissues (retina, hind limb, thymus and bursa) and the adult tissues (retina and spleen) are very similar to that of the embryonic erythrocyte. Thus, the extended reactivity of the monoclonal antibody to chickEE, maEE1, with additional tissues is, in at least the tissues examined, based on the presence of the chickEE glycoprotein and not on incidental cross-reactivity. The evidence presented in this paper for the widely-shared expression of chickEE antigen makes it necessary to reconsider the function of this component of the cell surface.

Animals↗
PubMed1986

Rearrangement of chicken immunoglobulin genes is not an ongoing process in the embryonic bursa of Fabricius.

We report a molecular analysis of the chicken Ig loci in single bursal follicles from 3- to 7-week-old chickens. Each follicle contained between 10(5) and 3 X 10(5) cells. The Ig gene rearrangement patterns obtained were compared to the pattern observed with the corresponding total bursal DNA. The results obtained for the light chain locus imply that a very small number (two on average) of rearrangement events takes place in each follicle. For the heavy chain locus similar results were obtained, each follicle showing a more restricted pattern than the total bursa. These data favor a model in which each follicle is colonized by a very few prebursal stem cells that are committed to a particular Ig gene rearrangement at the very beginning of the development of the embryonic bursa. The role of the bursa as the organ in which such a committed stem cell population for the B-cell lineage arises is discussed.

Animals↗
PubMed1986

Counting components of the chicken's B cell system.

At the risk of representing a chicken as a hybrid between a hummingbird and an ostrich, we can summarize the preceding sections and order-of-magnitude estimates as follows. Chicken B lymphocytes are derived from less than 10(5) lymphoid precursor cells, which either have already rearranged their Ig genes before they colonize the embryonic bursa, or (more probably) rapidly give rise to cells with rearranged genes within the bursa's 10(4) follicles. Since the bird's functional germline Ig V genes are few in number (less than or equal to 10?), most rearrangements have similar outcomes. The B cells proliferate rapidly in the bursa, in an antigen-independent manner, undergoing somatic modifications of their Ig V genes at a high rate (probably at least once in every 10(3) cell divisions). In the young chick, B cells are produced in the bursa at a rate of 10(7) to 10(8) per d; many of these die but the rest contribute to formation of the adult bird's B cell pool of about 10(10) lymphocytes, with a repertoire of at least 10(6) different antibody specificities. the bird's B cells are entirely self-renewing, in the sense that none are derived from Ig-negative precursors at any time after hatching.

Animals↗
PubMed1985

Clones of B lymphocytes in individual follicles of the bursa of Fabricius.

To discover whether individual bursal follicles can contain clones of B lymphocytes, we estimated the numbers of lymphoid cell precursors populating single follicles in two types of chicken chimera. The first type was produced by establishing parabiotic connections between blood vessels of embryo chorioallantoic membranes. Under these conditions, and most likely during normal development, most follicles are populated by more than one, but less than ten, precursor cells. However, in a second type of chimera, a cyclophosphamide-treated chick reconstituted with normal bursal cells, most follicles in the reconstituted bursa are clonal (their lymphocytes are derived from a single precursor cell). Individual follicles can readily be isolated from bursae of reconstituted birds and should be useful in studies of B cell development.

Animals↗
PubMed1985

Immunoglobulin-bearing stem cells for clones of B (bursa-derived) lymphocytes.

Treatment of neonatal chickens with cyclophosphamide depletes bursal lymphocytes while maintaining the bursal epithelium intact. The bursae of normal young chickens contain "bursal stem cells" which can reconstitute the lymphoid compartment in the bursa of the cyclophosphamide-treated recipient. Using bursal stem cells from IgM allotype-heterozygous donors we show that most bursal follicles in the reconstituted host are colonized by single stem cells which are committed to the expression of one or other IgM allotype. In addition we show that the reconstituting bursal stem cells express allelically excluded surface IgM at the time of transfer. Our results suggest that B lymphocyte numbers in hatched chickens are maintained by self-renewal of committed precursors rather than by de novo production from multipotential stem cells.

Animals↗
PubMed1984

A monoclonal antibody recognizes an epitope common to an avian-specific nuclear antigen and to cytokeratins.

X3, a monoclonal antibody of unusual specificity, is described. This antibody reacts with one or more cytokeratin polypeptides and also reacts with an avian (chicken, quail) nuclear antigen that appears to be present in all cell types (chicken) tested, although with variable staining pattern and intensity. This antigen is distinct from the cytokeratins but does have an epitope in common with this class of proteins. It disappears from the nucleus during the early stages of cell division and reappears during anaphase as a granular cytoplasmic structure. In late telophase the antigen is relocated in the nucleus. This antigen, which we have designated as avian-specific nuclear antigen ( AVNA ), is not associated with chromatin or ribonucleoproteins. From immunoblotting experiments on chicken fibroblast nuclei, AVNA is probably a complex composed of one or several polypeptides, one of which has a molecular weight of approximately 60 kD. The proteins were identified as nuclear matrix proteins rather than pore complex-lamina proteins by immunoblotting experiments on the purified nuclear matrix of chicken erythrocytes. The major polypeptide had a molecular weight of 60 kD and the minor polypeptide a molecular weight of 69 kD.

Animals↗
PubMed1983

Genetic control of the response of chicken T lymphocytes to concanavalin A: cellular localization of the low responder defect.

Genetic variation in the response of chicken lymphocytes to the T cell mitogen concanavalin A (Con A) has previously been studied by assaying tritiated thymidine [( 3H]dThd) uptake of cultured cells following mitogen stimulation. Our present results show, firstly, that low [3H]dThd uptake (e.g. in cultures of Con A-stimulated cells from low responder CB, CC or G-B1-lo birds) is correlated with low proliferative activity and with reduced capacity to form Con A-dependent T cell colonies in semi-solid agar. Secondly, in cultures containing mixtures of cells from high and low responder birds, the cells from each partner respond independently to Con A (there is neither suppression of high responder, nor activation of low responder cell proliferation). Finally, Con A-stimulated cultures of high responder cells respond better to T cell growth factors, as well as producing more growth factor activity, than cultures of low responder cells. These results suggest that the basis for the low responder phenotype is an intrinsic inability of low responder T lymphocytes to respond to Con A by differentiating into growth factor-sensitive blast cells.

Animals↗
PubMed1983

Characterisation of Concanavalin A-binding glycoproteins from mouse splenic leukocytes by two-dimensional electrophoresis: preferential binding of incompletely glycosylated forms of H-2 antigen to the lectin.

Concanavalin A (Con A)section-binding proteins from mouse spleen leukocytes were characterised by two-dimensional electrophoresis of material precipitated, by Con A plus anti-Con A, from lysates of biosynthetically-labelled cells. Although most cell surface (iodinatable) proteins are known to bind Con A, some of the major Con A-binding proteins detected by immunoprecipitation, after a four-hour biosynthetic labelling period, are not iodinatable and are probably intracellular. Thus the major biosynthetically labelled Con A-binding species are: (i) a non-iodinatable, high molecular weight glycoprotein (C-145); (ii) intracellular precursors of secretory immunoglobulins (IgM and, probably, IgA); (iii) immature (not fully-sialylated) forms of H-2 D and K antigens; and (iv) Ia antigens. In the case of the H-2 antigens, (and possibly of other cell surface proteins) the selection of immature forms by Con A is not due to lack of biosynthetic labelling of mature products, but to preferential binding of Con A to incompletely glycosylated molecules.

Animals↗
PubMed1983

Monoclonal antibody which recognizes a common antigenic determinant on intermediate filament proteins, actin, and myosin.

A monoclonal antibody is described which reacts with the intermediate filament proteins vimentin, desmin, keratins, actin, and myosin. This is the first report of an epitope common to intermediate filament proteins and myosin. X1, the wide-spectrum monoclonal antibody in question, was isolated in the course of screening monoclonal antibodies to chicken thymocytes. Cross-reactivities were investigated by immunofluorescence on various types of cultured cells and sectioned tissues, ELISA with a panel of purified antigens, immunoprecipitation, immunodot tests, and immunoblotting.

Actins↗
PubMed1983

Monoclonal antibodies against chicken lymphocyte surface antigens.

Spleen and lymph node cells of BALB/c mice, previously immunized with chicken thymic or bursa cells, were fused with Sp2/0-Ag14 mouse myeloma cells. Hybridomas from two fusions were selected on the basis of reactivity of their secreted antibodies towards thymic or bursal tissues in an indirect immunofluorescence assay. Four monoclonal antibodies reacting with different cell surface proteins of chicken lymphocytes were characterized, as follows. One antibody (IgM X.14) reacted only with cortical thymocytes, and precipitated material of apparent molecular weight (AMW) 65,000 (65 kD), 125 kD, and 180 kD from these cells. A second antibody (IgGl L.17) reacted with both bursa- and thymus-derived lymphocytes, but with different high molecular weight glycoproteins (AMWs 210 kD and 180 kD, respectively) on the two cell types. These proteins may be homologues of the previously described mouse B-220 and T-200 antigens. A third antibody (IgGl L.22) reacted with a protein of AMW 70 kD present on bursa-derived cells of some, but not all, chicken strains. Genetic analysis suggested that the presence of this protein was controlled by a single gene not closely linked to the major histocompatibility complex. A fourth antibody (IgG2b L.43) reacted with bursa-derived cells, macrophages and fibroblasts, but not with thymus-derived lymphocytes. L.43 precipitated material of AMW 23 kD from bursal cells.

Animals↗
PubMed1981

Biochemical characterization of avian T lymphocyte-specific antigens.

Sera from rabbits injected with quail thymocytes were absorbed on quail bursal and liver cells. The absorbed sera reacted with avian T but not B lymphocytes in an immunofluorescence assay. Material precipitated by the anti-T antisera from lysates of radioiodinated chicken or quail thymocytes was analyzed by one- and two-dimensional electrophoresis. Of two anti-T cell antisera studied in detail, one reacted mainly with a protein of an apparent molecular weight of 45 000 - 55 000, and the other with a protein of an apparent molecular weight 65 000 - 70 000. These proteins may be homologues of previously described mammalian T lymphocytes-specific antigens.

Animals↗
PubMed1980

Biosynthesis of two forms of IgM heavy chains by normal mouse B lymphocytes. Membrane and secretory IgM.

A study of the biosynthesis of IgM by purified mouse spleen lymphocytes showed that these cells synthesize both 8 S membrane IgM and 19S secretory IgM, which is identical with plasma cell IgM except in its kinetics of processing, assembly, and secretion. The heavy (mu) chains of these two types of lymphocyte IgM differ in their ultimate fate, in processing, isoelectric point, and peptide composition. The separate precursors of the two mu chains have very similar mobilities in sodium dodecyl sulfate polyacrylamide gel electrophoresis, but they can be distinguished by the use of endoglucosaminidase H (endo-H) to remove core sugars, by two-dimensional electrophoresis, and by one-dimensional gel analysis in pulse-chase experiments. CNBr peptide patterns of intracellular "secretory" mu chains of lymphocytes and plasma cells were similar, but membrane mu chains had a COOH-terminal peptide different in structure from that of secreted mu chains, with a higher apparent molecular weight.

Animals↗