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Biomedical subjects

G W Butcher

Publications and source records attributed to G W Butcher.

At least 91 records · Page 5Linked to original sources
PubMed1988

Major histocompatibility complex control of NK-related allogeneic lymphocyte cytotoxicity in rats. The contributions of strong and medial transplantation antigens.

Allogeneic lymphocyte cytotoxicity (ALC) describes the elimination of allogeneic lymphocytes in vivo by an NK-related activity. There is evidence that ALC is demonstrable between donor and recipient when these are incompatible at MHC gene loci alone. Since ALC is a property of T cell-deficient nude rats, the role of the MHC in this rejection process needs further study. We have determined the contribution of the MHC to ALC using congenic and recombinant rats. In our analysis we have assumed that ALC involves the recognition of classic alloantigens by clonally distributed effector cells as for other examples of transplant rejection, although this is not yet proved. Strong ALC was measured between congenic rats that differed for MHC genes only. Non-MHC incompatibility alone did not elicit ALC. In the presence of MHC incompatibility the strength of ALC generated in a recipient was dependent on non-MHC genes. The PVG background generated high ALC responses whereas ALC was not measured in the DA rat. However ALC was measured in the congenic PVG-RT1avl (DA) rat. The contributions of classic class I (RT1.A), class II (RT1.B/D), and medial transplantation (RT1.C) regions of the rat MHC were determined by comparing different recombinant donors into the same recipient strain. Single region differences alone in any of these three MHC regions did not elicit full ALC. In two sets of transfers a combination of RT1.B/D and RT1.C region incompatibility was sufficient to generate a full allogeneic response. It can be concluded that the controlling element for allogeneic lymphocyte cytotoxicity is in the RT1.B/D-RT1.C region of the rat MHC.

Animals↗
PubMed1988

Monoclonal antibodies to 13-deoxy-gibberellins.

The production and characterization of two high affinity rat monoclonal antibodies to 13-deoxy-gibberellins is described. Hybrid myelomas were derived from rats immunized with an immunogenic keyhole limpet hemocyanin-gibberellin conjugate, linked at carbon-3 to gibberellin A(4) via a hemisuccinate bridge. The selected monoclonal antibodies were characterized by a competitive radioimmunoassay.

Journal Article↗
PubMed1987

Serological evidence for a defect in RT1.B (I-A) expression by the BDIX rat strain.

Astrocytes, astrocytic cell lines and endothelium from BDIX rats were stimulated with recombinant interferon-gamma (IFN-gamma) and the expression of MHC molecules quantified using an enzyme immunoassay (EIA). Using the two mouse anti-RT1.B monoclonal antibodies MRC OX4 and OX6, previously described as recognizing a monomorphic determinant on RT1.B, as well as polyvalent rabbit anti-rat class II antisera, we were unable to demonstrate any induction of RT1.B molecules on these cells under conditions that induced RT1.B expression in all other strains tested. In contrast, RT1.D locus class II molecules, detectable by the antibody MRC OX17, are more strongly expressed in BDIX than in other strains. In experiments using BDIX lymphocytes, this serologically detected defect in RT.1B expression was confirmed using four additional mouse anti-mouse I-Ak monoclonal antibodies, which cross-reacted on all rat strains tested except BDIX. It appears likely that BDIX rats lack either a structural or controlling gene required for RT1.B expression.

Animals↗
PubMed1986

Differential expression of Ia and Ia-associated invariant chain in mouse tissues after in vivo treatment with IFN-gamma.

B10.BR mice were injected i.v. with varying doses of recombinant IFN-gamma on three consecutive days. In tissue sections of 13 organs, the distribution of Ia antigens and Ia-associated invariant chain (Ii) was studied by using an immunoperoxidase technique. In the control animal, Ia and Ii were shown to be co-expressed in most tissues. However, on Kupffer cells, a small number of hepatocytes, and a subset of lymphocytes in lymph nodes and in the splenic red pulp only Ii, and no Ia, was detectable. In contrast, strongly Ia+ interdigitating reticulum cells of T-dependent areas of lymph nodes and spleen were only weakly stained for Ii. IFN-gamma treatment resulted in a dramatic increase of MHC antigen expression throughout the body, with striking differences in the inducibility of certain tissues for Ia and Ii: Bronchial epithelium was clearly induced to express the invariant chain, whereas Ia antigens remained entirely absent. Moreover, in kidney tubules and colon epithelium, Ii was induced more broadly than Ia. In contrast to the induction of Ii on endothelial cells of larger vessels in kidney, heart, and lungs, no de novo expression of Ia or Ii in capillary endothelial cells was observed. The number of detectable Ia+/Ii+ interstitial dendritic cells considerably increased upon exposure to IFN-gamma. Neither neurons nor glial cells were induced to MHC antigen expression. Our data demonstrate that IFN-gamma applied i.v. is a potent inducer or enhancer of Ia antigens and invariant chain in a variety of cell types.

Animals↗
PubMed1986

Evidence for a possible regulatory gene (Suc-1) controlling sucrase expression in mouse intestine.

Assays for sucrase carried out on intestinal sonicates prepared from 18 different strains of mice revealed a threefold variation in specific activity, the values for CBA/Ca mice being significantly less than for any other strain. Further comparison of the CBA/Ca versus the C57BL/6J mouse showed this deficiency, which became established 2-4 weeks after birth, to apply to isomaltase as well as sucrase but not to maltase or trehalase. Backcross experiments indicated that this deficiency in sucrase activity was inherited as a single codominantly expressed genetic factor. The ability of the CBA/Ca mouse to regulate sucrase activity in response to changes in diet was also reduced compared to that of the C57BL/6J mouse. No difference could be detected in the affinity of sucrase for its substrate or in the ability of heat to denature sucrase prepared from CBA/Ca and C57BL/6J mice. It is suggested that part of the regulatory region of the gene coding for sucrase-isomaltase is modified in the CBA/Ca mouse and that this locus should be given the notation Suc-1 for future reference.

Animals↗
PubMed1986

Physical association between the peribacteroid membrane and lipopolysaccharide from the bacteroid outer membrane in Rhizobium-infected pea root nodule cells.

Monoclonal antibodies were used as cytochemical markers to study surface interactions between endosymbiotic Rhizobium bacteroids from pea root nodules and the encircling peribacteroid membranes, which are of plant origin. Monoclonal antibodies that react with Rhizobium lipopolysaccharide (LPS) or with a plant membrane glycoprotein were used as markers for material from the bacteroid outer membrane or the peribacteroid membrane, respectively. Membrane-enclosed bacteroids were isolated from nodule homogenates by sucrose gradient centrifugation, and the encircling peribacteroid membrane was released by mild osmotic shock treatment. Using an immunochemical technique (sandwich ELISA), it was shown that 1-5% of the LPS antigen released into the peribacteroid fraction by mild osmotic shock treatment was physically associated with peribacteroid membrane through a detergent-sensitive linkage. This association could be visualized when freshly prepared peribacteroid material was immobilized on gold grids and examined by electron microscopy after dual antibody immunogold treatment and subsequent negative staining. The distribution of LPS antigen within infected nodule cells was also investigated by immunogold staining for thin sections of nodule tissue fixed in glutaraldehyde, and a close association between LPS antigen and peribacteroid membrane was often seen.

Cell Membrane↗
PubMed1985

Monoclonal antibodies to antigens in the peribacteroid membrane from Rhizobium-induced root nodules of pea cross-react with plasma membranes and Golgi bodies.

Three rat hybridoma lines that produced monoclonal antibodies reacting with the peribacteroid membrane from Pisum sativum were isolated, and these all appeared to recognize the same antigenic structure. Using one of these monoclonal antibodies, AFRC MAC 64, electron microscopy of immunogold-stained thin sections of nodule tissue revealed that the antigen, present in the peribacteroid membrane, was also found in the plant plasma membranes and in the Golgi bodies, but not in the endoplasmic reticulum. When peribacteroid membrane proteins were separated by SDS-polyacrylamide gel electrophoresis and transferred to nitrocellulose by electro-blotting, it was found that MAC 64 bound to a series of protease-sensitive bands that migrated in the mol. wt. range 50-85 K. The epitope was sensitive to periodate oxidation and its structure may therefore involve the carbohydrate component of a membrane glycoprotein. We suggest that this structure originates in the Golgi apparatus and is subsequently transferred to the peribacteroid membranes and plasma membranes. The monoclonal antibody also reacted with peribacteroid membranes from nodules of Vicia and lupin, and with plasma membranes and Golgi membranes from uninfected plant cells, including root tip cells from onion (Allium cepa), indicating that the antigen is highly conserved in the plasma membranes of plant cells.

Antibodies, Monoclonal↗
PubMed1985

In vivo prevention of thyroid and pancreatic autoimmunity in the BB rat by antibody to class II major histocompatibility complex gene products.

Evidence is accumulating that the development of insulin-dependent diabetes mellitus involves autoimmune phenomena, both in the human and in the BB rat model. A strong association is observed in both cases with alleles of the class II major histocompatibility complex (MHC). Results of the present study show that autoimmune phenomena, as assessed by the presence of clinical diabetes or histological thyroiditis, are prevented by the injection of monoclonal antibodies to class II gene products in the BB rat. Immunosuppression was specifically obtained with a monoclonal antibody to the murine I-E equivalent, as opposed to the murine I-A equivalent, of the rat major histocompatibility complex. This represents indirect evidence for I-E subregion control of immune responses to islet cell and thyroid antigens in the BB rat model. The frequent occurrence of anaphylactic type deaths in young (1 month old) animals receiving more than six weekly injections of partially purified homologous (rat) monoclonal antibodies to rat class II gene products underscores the potential risks of this type of immunotherapy. The presumed immunologic mechanism (IgE antibody) and its specificity (anti-allotype, anti-idiotype, or anti-impurity) must be clarified to assess the risks and feasibility of this type of therapy.

Anaphylaxis↗
PubMed1985

Genetics of the rat CT system: its apparent complexity is a consequence of cross-reactivity between the distinct MHC class I antigens RT1.C and RT1.A.

The rat CT antigens are a system of medial histocompatibility antigens linked to RT1, the rat major histocompatibility complex (MHC). They have aroused interest firstly because, despite their extreme serological weakness, they are targets for 'unrestricted' cytotoxic T lymphocytes (CTL); and secondly because they have appeared to represent a complex genetic system in terms both of the number of genetic loci involved and the number of distinguishable antigenic specificities expressed. The CT system was originally defined by the reactions of LEW anti-F344 (RT1l anti-RT1lv1) secondary in vitro CTL. These CTL reacted strongly on DA(RT1av1) targets, but much more weakly on AUG or PVG (RT1c) targets. We have used the recently derived RT1 recombinant rat strains PVG.R19 (RT1.Aav1Iav1Cc) and PVG.R20 (RT1.AcIcCav1) to investigate the genetic control of this system. Contrary to previous interpretations, the results are consistent with a model in which CT is a single locus, which maps to the RT1.C region. In addition, our results demonstrate that there is cross-reactivity of anti-RT1C CTLs on RT1A products, and we suggest that the earlier placement of a CT locus in the RT1.A region was probably incorrect and a consequence of this cross-reactivity.

Animals↗
PubMed1984

The alloantigenic organization of RT1Aa, a class I major histocompatibility complex molecule of the rat.

Over 300 monoclonal IgG alloantibodies have been prepared against RT1Aa , the class I major histocompatibility complex molecule of the DA rat. In this study a combination of techniques is exploited to show that all these antibodies can be allocated to 9 antigenic sites which form a continuous antigenic surface, that is, no site is completely isolated from the rest. The results suggest that techniques for the identification of antigenic sites using competitive inhibition of monoclonal antibody binding are generally valid, in the sense that competition between antibodies appears most commonly to represent competition between combining sites for a structural feature of the antigenic surface. From the distribution of antibodies between sites, it is clear that the RT1Aa molecule has three immunogenic areas against which nearly all the antibodies studied were directed. Of these areas one is both antigenically complex, consisting of four closely spaced sites, and remarkably immunodominant. Antibodies directed at sites between the major areas are extremely rare.

Animals↗
PubMed1984

Monoclonal antibody screening: two methods using antigens immobilized on nitrocellulose.

The dot-immunobinding assay of Hawkes et al. [R. Hawkes, E. Niday, and J. Gordon (1982) Anal. Biochem. 119, 142-147] has been modified such that many antibody solutions are screened simultaneously on dots of antigen applied to a single sheet of nitrocellulose using very small amounts of both antigen and antibody solutions. This method is also used in the assay of antibody binding on dots of components of the antigen after enzymatic digestion and chromatographic fractionation and to dots of compounds which may be chemically related to the antigen. An aluminum template for screening Western blots with a number of different antibody solutions on a single sheet of nitrocellulose is also described. Possible applications of the dot-immunobinding assay in screening for virus are discussed.

Animals↗
PubMed1984

The new recombinant haplotypes r19 and r20 in RT1, the MHC of the rat.

Two new recombinants, designated r19 and r20, have been found in RT1, the rat major histocompatibility complex. In both recombinants the A and I regions appear to be derived from one parental haplotype, and a further region, able to induce both skin graft rejection and cytotoxic lymphocytes is derived from the other. The properties of this region appear similar to the previously described RT1C and the putative genotypes of the PVG X R19 and PVG X R20 congenic lines are therefore AaIaCc and AcIcCa, respectively. Evidence suggesting that the two recombinants may not be reciprocal is discussed.

Animals↗
PubMed1984

Localized conformational changes induced in a class I major histocompatibility antigen by the binding of monoclonal antibodies.

We describe two monoclonal antibodies, R3/47 and YR1/1, directed against different epitopes of the expressed rat class I major transplantation antigen RT1Aa, that interact with each other so that the binding of one antibody, YR1/1, is greatly enhanced by the binding of the other. The positive interaction between R3/47 and YR1/1 also occurs when using RT1Aa molecules solubilized from cell membranes in detergent. It is therefore unlikely that the molecular environment of the membrane contributes to the interaction. The ability of R3/47 to modify the YR1/1 determinant on the RT1Aa molecule is mediated without any significant loss of potency by highly purified monomeric Fab fragments. This result suggests that the binding of R3/47 to the RT1Aa molecule alters the YR1/1 determinant by initiating a propagated conformational change in the antigen.

Animals↗
PubMed1982

Immune response genes controlling responsiveness to major transplantation antigens. Specific major histocompatibility complex-linked defect for antibody responses to class I alloantigens.

We have identified two major histocompatibility complex (MHC)-linked Ir genes that control the antibody response made by rats against class I major alloantigens. We have named these genes Ir-RT1Aa and Ir-RT1Ac. These Ir genes determine responsiveness of the immunized animal in a typical codominant fashion. There is no evidence so far for trans-complementation between low-responder haplotypes. Detailed studies of Ir-RT1Aa indicate that it controls the antibody response to at least two distinct alloantigenic determinants on RT1Aa molecules. These class I molecules thus behave like hapten-carrier conjugates when the response against the carrier is under Ir gene control. Analysis of the origin of alloantibody-forming cells in tetraparental radiation chimeras indicates that Ir-RT1Aa must control the provision of effective help to B cells. In many respects therefore, the properties of Ir-RT1Aa are broadly similar to those described for Ir genes controlling antibody responses to conventional antigens. The existence of apparently conventional Ir genes controlling the antibody response to major alloantigens strongly suggest that the processing of these transmembrane molecules by host antigen-presenting cells is a prerequisite for immune induction, and that it is the MHC of the responder rather than that of the allograft to which T helper cells are restricted in alloimmune responses in vivo.

Animals↗
PubMed1982

The alloantibody response in the allogeneically pregnant rat. I. The primary and secondary responses and detection of Ir gene control.

We compared the primary pregnancy-induced alloantibody responses with secondary pregnancy-induced responses and with conventional immunologic responses and found there are profound differences. Conventional and secondary responses produce strong lytic sera and readily detectable immunologic memory. The primary pregnancy-induced responses lack memory and produce alloantisera or widely variable titer. Such sera were rarely directly lytic. Pregnancy-induced primary responses detect MHC Ir gene control, even when the allogeneic difference is a complete HMC haplotype. The kinetics of the primary and secondary pregnancy-induced alloantibody responses against DA were different. We conclude that the primary pregnancy-induced alloantibody response is very different immunologically from conventional and secondary pregnancy-induced alloimmunizations.

Animals↗