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Biomedical subjects

I Karakoz

Publications and source records attributed to I Karakoz.

At least 37 records · Page 2Linked to original sources
PubMed1985

The effect of thymectomy on immunological tolerance to human serum albumin in chickens.

The effect of thymectomy performed on the day of hatching has been studied in chickens rendered tolerant by 100 mg of HSA injected also on the day of hatching. After challenge at the age of 6 and 9 weeks, no significant difference was observed between the group of tolerant chickens, in which the thymectomy was complete or incomplete, and the non-operated tolerant one. The delayed recovery from tolerance observed in mammals was not seen even in chickens in which thymus was removed completely and no thymic residue remained. The anti-HSA antibodies were even slightly higher in thymectomized birds than in the non-operated ones but the difference was statistically non-significant.

Animals↗
PubMed1984

Different importance of primary lymphoid organs for Rous sarcoma regression in inbred lines of chickens.

Resistance to progressive growth of tumours induced by Rous sarcoma virus is controlled mainly by genes linked to the B complex (the major histocompatibility complex) of the chicken. The effect of thymectomy and bursectomy on this resistance was studied in chickens from highly inbred lines and their F1 hybrids which differ by the genotype at the B complex and by the degree of genetically controlled resistance or susceptibility. The results show that thymectomy has considerable effect on growth of RSV-induced tumours in the CB line genetically resistant to progressive Rous sarcoma growth and little effect in (CB X IC)F1 (also genetically resistant) and (CC X IC)F1 (intermediate responders to RSV) hybrid chickens. Bursectomy influences the expression of this resistance to a lesser extent than thymectomy. The results indicate that resistance to the development of progressively growing tumours is of a complex nature, the individual components of the immune system are more or less important for its expression in different experimental models. Thus genetically defined animal models have become useful tools for studying carcinogenesis.

Animals↗
PubMed1984

Antibody-producing cells in chickens tolerant to human serum albumin.

Cells forming antibodies to HSA were determined by the haemolytic plaque technique in the spleens of chickens in which tolerance to HSA was induced on the day of hatching. After immunization with HSA 2 weeks after hatching, no anti-HSA PFC or their very low numbers were observed in chickens rendered tolerant by the dose of 100 mg HSA. In a considerable proportion of the chickens, in which tolerance was induced by 1 mg or 0.1 mg of HSA, PFC were detected, though in statistically significantly lower numbers than in control birds. In tolerant chickens receiving 100 mg of HSA after hatching, the number of PFC after immunization at 4 weeks of age was statistically significantly and at 6 weeks non-significantly lower than in the controls. After immunization with BSA at 4 weeks of age, chickens injected with 100 mg HSA after hatching had the number of anti-HSA plaque-forming cells higher than the controls, but the difference was not statistically significant.

Animals↗
PubMed1984

Induction of tolerance in chickens by low doses of human serum albumin administered after hatching.

The possibility was tested whether tolerance can be induced in newly hatched chickens by a single injection of HSA on the day of hatching in doses one or several orders lower than the dose employed in previous experiments (100 mg of HSA). Doses of 10 and 1 mg of HSA induced a statistically significant suppression of anti-HSA antibody formation after challenge at the age of 2 and 4 weeks. Injection of 0.1 mg of HSA into newly hatched chickens also produced a statistically significant decrease in antibody formation after challenge at 2 weeks of age.

Animals↗
PubMed1983

Morphological and biochemical studies on experimental allergic encephalomyelitis in inbred lines of chickens.

An attempt to establish the relation between morphological and biochemical indices determining the inflammatory state in brain after induction of allergic encephalomyelitis in chickens was taken up. Symptoms of encephalomyelitis were accompanied by the changes within T and B lymphocyte population and by distinct increase of activity of trypsin inhibitor and content of sialic acid in blood serum.

Animals↗
PubMed1982

Immunological unresponsiveness to HSA in chickens.

HSA injected into chickens after hatching induces suppression of anti-HSA antibody formation. Unresponsive chickens react by producing the anti-HSA antibodies earlier and more intensively after BSA challenge than after challenge with HSA. This effect cannot be ascribed to T cells, because they were found to play no substantial role in the unresponsiveness to HSA. Neither was active suppression, which could account for the depressed antibody production, detected. B cell inactivation seems to be the major mechanism involved in this unresponsiveness. However, some additional mechanism must prevent B cells of unresponsive chickens from producing anti-HSA antibodies after HSA challenge, although they are able to form them after immunization with BSA. We suggest that cellular interactions, either between B cells of different specificities or between B cells and macrophages, are responsible for this differential reactivity.

Animals↗
PubMed1980

In vivo effect of three transformation-defective mutants of subgroup C avian sarcoma viruses.

Three transformation-defective mutants derived from avian sarcoma viruses of subgroup C, td PR-RSV-C (Vogt), td B77 (Toyoshima) and td daPR-RSV-C (isolated in our laboratory), were injected intravenously into 12-day-old chicken embryos and intraperitoneally into newly-hatched chickens. Both Brown Leghorn chickens and F1 hybrids of two inbred chicken lines (C X I) were used. Haematological changes and formation of visible tumours were evaluated in animals kept for 8-9 months. All three td mutants produced in a significant proportion of intraembryonally injected animals haematological disorders which, in certain cases, resembled the anaemic and proliferative type of erythroblastosis. Most conspicuous symptoms of erythroblastosis were seen after td daPR-RSV-C which also gave rise to two sarcomas, containing transforming viruses. The possible character of oncogenic information retained or acquired by the TD mutants is discussed.

Anemia↗
PubMed1980

Long-term persistence of transformation-defective mutants of subgroup C in chickens and ducks inoculated early in life.

Three transformation-defective mutants derived from avian sarcoma viruses of subgroup C were injected intraembryonally and neonatally into leukosis-free chickens. Viruses persisted in the blood of all inoculated birds tested for 43 to 163 days after hatching. Similarly, these viruses persisted over more than one year in ducks injected intraembryonally. In two tested ducks virus titres in blood plasma were determined and it was found that they reached 10(2) and 10(3) infectious units per ml. The significance of td mutant persistence, particularly in relation to a possible recombination with chicken and duck src sequences, is discussed.

Animals↗
PubMed1978

Experimental allergic encephalomyelitis in chickens.

Experimental allergic encephalomyelitis (EAE) in chickens of the inbred lines IC, CB, WB and (CBxIC)F1 hybrids was investigated. The IC line and (CBxIC)F1 hybrids gave the best reactions. In bursectomized chickens only slight changes in brain were observed. The intensity of EAE in thymectomized chickens was highly suppressed. Using the anti-T and anti-B sera it was shown that, the percentage of EAE of B lymphocytes was increased. Among the used several immunosuppressive drugs which generally decreased inflammatory reactions in brain the best results were observed with azathioprine and actinomycin D. Moreover, cyclophosphamide gave the worse results which was shown in the same experiments. The aim of our experiments was to define the role of thymus and bursa of Fabricius and peripheral B and T lymphocytes in the course of EAE. Moreover, the effect of immunosuppressive drugs on EAE was studied.

Animals↗
PubMed1978

Persistence of immunological tolerance to HSA in chickens after cell transfer to immunosuppressed hosts.

The nature of immunological tolerance to HSA in chickens was analyzed by means of spleen cell transfers to 3-day-old, cyclophosphamide-treated, syngeneic recipients. The cell donors were 2-week-old tolerant or control chickens. The primary challenge with HSA was done 26 days after cell transfer. Spleen cells from both control and tolerant donors restored the immunoglobulin levels and the ability to produce antibodies to SRBC to normal. While cells from normal donors also reconstituted the ability to form antibodies to HSA, the recipients of cells from tolerant donors either did not form detectable amounts or formed only low titres of these antibodies. The ability of cells from normal donors to respond by anti-HSA antibody formation, when transferred together with cells from tolerant donors, was neither suppressed nor decreased. Thus, tolerance to HSA in chickens was not reversible and the existence of an active immune process, causing its duration, could not be demonstrated.

Animals↗
PubMed1978

Termination of tolerance to HSA in chickens.

A major part of chickens made tolerant to HSA at hatching formed anti-HSA antibodies when immunized with cross-reacting antigen, the BSA, at 4 weeks of age, although tolerant birds immunized with HSA produced no detectable antibody levels. Immunization with HSA + BSA did not prevent anti-HSA antibody formation in tolerant chickens, but it seems that the escape from tolerance is more rapid in birds immunized with BSA only than in those immunized with HSA + BSA and/or HSA only.

Animals↗
PubMed1977

Activity of various immunosuppressive drugs on tuberculin hypersensitivity reaction in chickens.

Drug induced immunosuppression of chicken immune response was studied in F1 hybrids of the CB and IC inbred lines. In tuberculin reaction complete inhibition of wattle swelling was induced by the administration of methotrexate, colcemid (1 mg/KBW), and 6-mercaptopurine. The cellular infiltration was substantially reduced in these cases. Cyclophosphamide and colcemid (0.1 mg/KBW) reduced partially the wattle swelling but had no apparent effect on the cellular infiltration. Acetinomycin D did not affect in measurable degree the wattle swelling. The histologic picture was in this case the same as in the control animals. The same drug administration schedule had less pronounced effect on anti-HSA antibody production. No anti-HSA antibody was found after the 500 mg/animal doses of 6-mercaptopurine. Significant reduction of anti-HSA titres was found after 50 mg/animal doses of 6-mercaptopurine, colcemid (1 mg/KBW), 25 MG/KBW or cyclophosphamide and after the methotrexate treatment.

Animals↗