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Preferential synthesis of IgE reaginic antibodies in rats immunized with alum-adsorbed antigens.

The reaginic antibody response to alum-precipitated ovalbumin (OA) and the dialyzed water-soluble extracts of ragweed (DWSR) and Alternaria tenuis (DWST) in several strains of rats appeared to be wholly an IgE response. There was no evidence of a heat-stable (IgGa) antibody to OA, DWSR and DWST in the sera of the rats immunized with these antigens suspended in alum. Wistar-Furth and Lew inbred and hooded outbred rats produced comparable amounts of reaginic antibody after immunization with DWST, but BN inbred rats failed to generate a reaginic response to this antigen. The amount of antigen-induced histamine release from rat peritoneal mast cells did not always correlate with the level of circulating IgE-specific antibody.

Adsorption

Effect of antigen dose on the secondary IgE response in BN rats.

Inbred Brown Norway rats were immunized at day 0 with a single dose of ovalbumin and 1 mg A1(OH)3. Various doses of ovalbumin without adjuvant were given at day 28. The secondary IgE antibody was antigen dose-dependent. Total serum IgE levels decreased after immunization and during the IgE antibody response.

Aluminum Hydroxide

[Orthotopic liver transplantation in rats. Prolonging of survival time of allotransplants using cyclosporin A in an acute rejection model].

Livers from inbred DA rats were transplanted orthotopically into inbred BN rats. Within 15 days all animals died due to rejection of the transplant. However, when rats were treated with Cyclosporin A (four different regimens) they survived for at least 60 days, even if therapy was withdrawn at day 28. It could be shown that the histologic changes in the graft stood in an inverse relationship to the extent of immunosuppressive therapy.

Alkaline Phosphatase

Genetic control of the in vitro responses of rat blood lymphocytes. II. Number of loci involved and linkage with in vivo antibody formation.

Blood lymphocytes from the inbred rat strains AS and BN differ in the magnitude both of their in vitro proliferative response to different mitogens and of their in vivo antibody response to the mitogenic fraction of phytohemagglutinin (PHA). We have examined the segregation of in vitro responsiveness to PHA in (AS X BN)F1 X BN backcross rats and have tried to correlate it with other characters that vary in backcross rats. In vitro responsiveness is regulated by one or a few loci, is linked to the in vitro responsiveness to B lymphocyte mitogens and the in vivo antibody response to the mitogenic fraction of PHA, but is not linked to the major histocompatibility locus (Ag-B) nor to the frequency of short-lived small Ig-negative lymphocytes in blood. Lymphocytes from high-responder rats have a shorter lag period before the onset of DNA synthesis in vitro than low-responder rats, and possibly also a higher number of in vitro responsing cells. To explain our findings, that the same gene og genes regulate in vitro responsiveness to different mitogens and in vivo antibody response to the mitogenic fraction of PHA, we suggest that the gene or genes act in an immunologically unspecific manner on the regulation of lymphocyte proliferation in vitro as well as in vivo.

Animals

Scanning electron microscopic study of hyperacute rejection in the inbred rat.

Twenty skin-presensitised Lewis rats received kidney transplants from (Lewis X BN)f1 rats. Two grafts each were withdrawn at intervals from 1--120 min and examined using a scanning electron microscopic (SEM). A series of Lewis to Lewis isografts served as control. In hyperacute rejection at just 1 min spider-like fibrin fibres and platelets could be observed in small arteries, where the endothelium was severely altered. In these regions at 2 and particularly 5 min a fibrin network often contained platelet aggregates, mechanically altered erythrocytes as well as different kinds of leucocytes. This coagulation process progressed with time and resulted in a complete vascular occlusion at 30--60 min.

Animals

Humoral antibody response in rat renal allotransplantation.

Female inbred Fischer (F344) rats were grafted with kidneys from female BN rats. Humoral antibodies in some of the recipients were demonstrated as early as 3 days after transplantation: (1) antibodies bound to the graft were detected by mixed agglutination tests with graft sections and erythrocytes of the donor as indicator cells; (2) lytic and agglutinating antibodies against donor strain erythrocytes were demonstrated in the recipients' sera by hemolysis in agar gel and dextran hemagglutination tests; and (3) similar antibodies secreted by a significant number of cells were detected in the recipients' spleens by plaque assay. The antibody response of the recipients was directed against a single antigen, designated N, which was shown to be present on erythrocytes of 57% of Fischer strain rats and was shared by erythrocytes of all rat strains tested (BN, Lewis, Wistar, ACI, MAXX, and Buffalo). The N antigen did not seem to belong to any known rat histocompatibility antigen system. Segregation of the gene coding for this antigen within the Fischer strain would indicate residual genetic heterogeneity. Evidence was presented that this antigen is present not only on erythrocytes, but also on other cells including splenocytes.

Adrenal Glands

Age-related reduction in pituitary corticotropin-releasing hormone receptors in two rat strains.

Open field behavior and age-related changes in anterior pituitary corticotropin-releasing hormone (CRH) receptors, as well as plasma ACTH levels, were measured in two inbred rat strains. The strains utilized were Wistar Kyoto (WKY) and Brown-Norway (BN), the former characterized by shorter life-span and hyper-reactivity to stressors as compared to the latter. Behaviorally, WKY rats showed hyper-responsivity to a novel environment as indicated by their delay in entering the open field, increased grooming, reduced rearing, and reduced locomotion. These strain-dependent behavioral differences were not affected by aging. The binding capacity of CRH receptors was similar in both strains and Bmax values were decreased (25-27%) with aging, with no changes in Kd values. In contrast, plasma ACTH levels were 67% higher in WKY than in BN rats but did not change with aging. Thus, despite pituitary CRH receptor down regulation, plasma ACTH levels following decapitation were sustained during aging. This suggests the presence of some compensatory factors in the hypothalamic-pituitary axis regulation which sustain ACTH response during aging. Furthermore, the findings indicate that higher plasma ACTH levels and hyper-reactivity to a novel environment are inversely correlated with longevity in the rat.

Adrenocorticotropic Hormone

[The effect of donorspecific antigen type for active enhancement of renal-allografts in the histoincompatible inbred rats (author's transl)].

49 kidneys of male LBNF1-rats were transplanted into male Lewis-rats. BN-rats were used as a source of antigen. Control animals survived 16.1 +/- 1.8 days. 5 recipients were preteated with donorspecific living cells, 7 with semisoluble and 5 with low dosage of soluble antigen. The living cell-pretreatment showed the best effect for the active enhancement, the soluble antigen the least. The pretreatment with 6 mg protein/kg bw. caused the sensibilization of recipients. At the time of transplantation lymphcytotoxic antibody titers were detected in all recipients with pretreatment of living cells, but no titer in other groups. Renal allografts with elevated postopertive titer were rejected rapidly.

Animals

Genetic control of antibody responses to PHA in inbred rats.

Phytohemagglutinin (PHA-P; Difco) contains four immunogenic components. The antibody response in rats to two of these components is shown to be genetically determined: AS rats are high responders and BN rats are low responders to both antigens. Responsiveness to the two components segregates independently as autosomal, dominant traits in a manner that is compatible with a one-gene hypothesis for both responses. The antibody response to the mitogenic fraction of PHA segregates together with the in vitro mitogenic response to PHA and to other mitogens. These responses are not linked to the major histocompatibility complex (MHC) of the rat. The antibody response to a nonmitogenic fraction from PHA is, however, linked to the MHC.

Animals

Effect of macrophages and antibodies on in vivo growth of Moloney sarcoma in the rat.

Brown Norway and Lewis rats were challenged with a Brown Norway Moloney sarcoma tumor, MST-1, admixed with nonimmune peritoneal exudate macrophages syngeneic to the host; or admixed with nonimmune peritoneal exudate macrophages and hyperimmune anti-MST-1 antibodies. In vivo growth of MST-1 in BN and Lewis rats was inhibited by admixing Brown Norway or Lewis macrophages, respectively, with BN anti-MST-1 antibodies. The inhibiting BN antibodies were of the IgG2 class, lacking IgG2a antibodies. Brown Norway anti-MST-1 of IgG2 class without macrophages did not affect growth of MST-1. Brown Norway and Lewis anti-MST-1 antibodies of IgG2a class enhanced tumor growth, whether admixed with macrophages or not. Anti-MST-1 antibodies of IgM and IgG1 classes did not influence tumor growth. Peritoneal exudate macrophages removed from Lewis donors 8 to 10 days after inoculation of MST-1 inhibited completely growth of the challenge tumor; macrophages of Brown Norway origin were inhibitory only when harvested from hyperimmune donors, that is, 40 or more days after inoculation of MST-1. Macrophages from hyperimmune donors were specifically cytotoxic to MST-1 and did not inhibit an unrelated syngeneic BN tumor of chemical origin.

Animals

Genetically controlled autologous immune complex glomerulonephritis in rats.

A study was conducted on the disease susceptibility of inbred strains of rats to experimental autologous immune complex glomerulonephritis (AIC). Three strains representing two different H-1-haploytpes developed severe glomerulonephritis within 3 months in response to a single injection with equal doses of an autologous primary tubular epithelial fraction and complete Freund's adjuvant (Lewis, AS (H-11)) and Lew.BDV (H-1d)).By contrast, two strains of the H-1 haplotype H-1n (BN and Lew.BN) showed no proteinuria and no immunohistologic findings during that time. Hybrids of Lew.BN and Lewis, subjected to the same immunizing procedure, showed a later onset of the disease as compared to the responder parent. The possible relationship between responder status and the major histocampatibility complex is discussed.

Animals

On the identity of lymphoid cells that stimulate the rat MLC and produce active enhancement.

The preimmunization of 10(7) Brown Norway (BN) rat lymphoid cells i.v. 1 week before (Lew X BN) F1 to Lewis renal grafting causes a state of immunologic enhancement. The BN lymphoid cells responsible for producing enhancement are the same cells that are capable of stimulating Lewis T cells in one-way MLCs. Thus active enhancement requires immunity to LD antigens, since SD +, LD- BN cells do not create a vigorous enhanced state.

Animals

Interaction with homologous erythrocytes of rat T cells which act as aggressors in the mixed lymphocyte reaction.

Substantial percentages of T-enriched spleen lymphocytes or thymocytes of inbred rats were found to form rosettes with the RBC of homologous strains. When an excess of RBC was used, essentially all of the rosette-forming subpopulation of lymphocytes was removed when the rosettes were separated by centrifugation. After depletion of the lymphocytes, reactive with RBC of one strain, most of the lymphocytes reactive with RBC of other strains could be recovered in the supernatant. A very large percentage of lymphocytes of the BN strain formed rosettes when a mixture of the RBC of five other strains was tested; the percentage was, however, somewhat lower than that predicted on the basis of complete additivity. Rosettes dissociated when warmed to 37 degrees C. The lymphocytes recovered were unable to form rosettes again. In nearly all instances, the subpopulation that formed rosettes with RBC of a given strain included essentially all of the lymphocytes that acted as aggressors against peripheral leukocytes or mytomycin C-treated thymocytes of that strain; the lymphocytes in the supernatant always retained activity as aggressors against the leukocytes of one or more other strains and retained their responsiveness to PHA. Lymphocytes recovered from rosettes, by warming to 37 degrees C, were highly reactive as aggressors in the MLR against the strain providing the RBC. Varying degrees of reactivity were noted against leukocytes of other strains.

Animals

Sequential quantitation of circulating immune complexes in syngeneic and allogeneic rats bearing Moloney sarcomas.

A Raji cell radioimmunoassay was employed to quantitate serially circulating immune complexes (CIC) in the sera of syngeneic BN rats and allogeneic Lewis rats bearing BN Moloney sarcomas. In syngeneic BN hosts the levels of CIC attained and the time-course of detection were related to the tumor dose, tumor mass, and regressive or progressive course of the tumor. In general, syngeneic rats that received larger tumor doses developed larger tumors and greater maximum levels of CIC. However, the amount of CIC was not always directly proportional to the tumor size, although this was nearly the case with regressor BN and Lewis rats. In rats with regressing tumors, CIC decreased to insignificant levels as the tumors disappeared. Progressor BN rats that received 20 and 10 X 10(6) tumor cells had higher and more sustained levels of CIC, but, shortly before the hosts died, despite an increase of tumor size, there was a decline of CIC. Progressor BN rats that received an initial inoculum of 0.5 X 10(6) tumor cells that grew to 44 mm maximum mean diameter had levels of CIC which were only slightly above levels of control rats. All allogeneic Lewis hosts rejected BN Moloney sarcomas, but had transient low levels of CIC coincident with tumor growth. Lewis rats had lower levels of CIC than BN rats bearing comparable masses of sarcoma.

Animals

Mixed leukocyte culture reactivity in operationally tolerant rats: Relationship of lymphocyte-mediated reactivity and serum-blocking activity.

Tolerance to Brown Norway (BN) allografts was induced in Wistar Furth rats by neonatal inoculation of BN bone marrow cells or mixtures of (W/Fu x BN)F-1 hybrid spleen and bone marrow cells. Lymphoid cells from rats in which operational tolerance had been induced (maintenance of BN skin graft for more than 100 days) were studied for mixed leukocyte culture (MLC) reactivity. Peripheral blood lymphocytes from 10 of 25 W/Fu rats operationally tolerant to BN skin grafts showed MLC reactivity when exposed to BN antigens in vitro, implying that some degree of MLC reactivity is compatible with prolonged skin graft survival. These same rats also showed cytotoxic activity to BN fibroblasts in vitro regardless of their MLC status. MLC is quantitatively decreased and possibly qualitatively altered as compared to that of control W/Fu lymphocytes. The decrease was specific for the tolerated antigens. Serum from the tolerant rats inhibited cytotoxic but not normal MLC reactivity of W/Fu cells against BN antigens.

Animals

Enhancement of rat renal allografts with monoclonal antibody.

Treatment of rat allograft recipients before grafting with donor spleen cells and whole, pooled antidonor alloimmune serum results in indefinite renal allograft survival. The enhancement is immunologically specific. In these experiments a monoclonal, homogenous anti-BN antibody was produced by a hybridoma clone created by fusing the mouse-P3 myeloma with spleen cells from Lewis rats immunized with BN lymphoid cells. The hybridoma supernatent enhanced survival of LBN renal allografts in Lewis recipients as effectively as whole Lewis anti-BN antiserum. Dilution of the hybridoma supernatent by tenfold or a hundredfold abrogated the enhancement effect.

Animals