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Biomedical subjects

J L Turk

Publications and source records attributed to J L Turk.

At least 199 records · Page 11Linked to original sources
PubMed1978

Delay in the development of the allergic response to metals following intratracheal instillation.

Intracheal intubation with the soluble metal salts potassium dichromate (K2Cr2O7) and nickel sulphate (NiSO4) causes a delay of up to 8 weeks in the development of delayed hypersensitivity to the specific agent. It is suggested that absorption of sensitizers by the respiratory route may, under certain circumstances, induce a state of specific immunological unresponsiveness, rather than necessarily lead to the development of a state of allergic sensitivity.

Animals↗
PubMed1977

Increased resistance in splenectomized mice to a methylcholanthrene-induced tumour.

Prior splenectomy increased the resistance of BALB/c mice to a syngeneic methylcholanthrene-induced ascitic tumour inoculated i.p. The survival rate of splenectomized mice was 81-6% while those of normal and sham-operated controls were 11-5% and 20% respectively. The effect of splenectomy, however, was seen only within the dose range of 10(3) to 10(4) tumour cells. This effect of splenectomy was abolished by the transfer to mice of serum from tumour-bearing mice, and of spleen cells from normal donors, immediately after the inoculation of tumour cells. Cell-free ascitis fluid did not abolish the effect of splenectomy. The findings suggest that there is a subpopulation of spleen cells which produces a tumour growth enhancing factor which is found in the serum of tumour-bearing mice.

Animals↗
PubMed1977

Sensitization with Cr, Ni and Zr salts and allergic type granuloma formation in the guinea pig.

Guinea pigs were sensitized to potassium dichromate, nickel sulfate and sodium zirconium lactate by three methods of immunization in Freund's complete adjuvant: Polak, split adjuvant, and maximization (modified Magnusson and Kligman). These were followed after 2 weeks by weekly intradermal injections of 25 microng of the metal salt. Delayed hypersensitivity-like reactions developed 3 to 12 weeks after initial injection. Reactivity, although strong with an increase in thickness of over 0.7 mm and/or diameter of erythema of over 8 X 8 mm, was frequently transient, the animal losing reactivity on subsequent skin test or after 2 or 3 skin tests. In two-thirds of the experiments using sodium zirconium lactate, delayed hypersensitivity-like reactions at 24 hr developed into nodular lesions which reached peak intensity at 8 days and histologically contained histiocytes with an epithelioid cell appearance and giant cells. In some experiments, sodium zirconium lactate-sensitive animals showed cross reactivity with potassium dichromate, but not with nickel sulfate.

Animals↗
PubMed1977

Modulation of delayed-type hypersensitivity and cellular immunity to microbial vaccines: effects of cyclophosphamide on the immune response to tularemia vaccine.

Treatment of guinea pigs with cyclophosphamide before immunization with killed tularemia vaccine in Freund incomplete adjuvant produced a prolongation and intensification of delayed-type hypersensitivity and in vitro lymphocyte transformation reactions to tularemia antigen. Such reactions resemble those ordinarily associated with the administration of live tularemia vaccine, killed vaccine in Freund complete adjuvant, or recovery from natural infection. The immunopotentiation lasted longer than that seen previously in other antigenic systems with this drug and was dependent on the dose of vaccine used. More intense delayed skin reactivity could be transferred into normal controls by cells from immunized donors pretreated with cyclophosphamide than by cells from immunized donors that were not pretreated.

Animals↗
PubMed1977

The value of an assessment of erythema and increase in thickness of the skin reaction for a full appreciation of the nature of delayed hypersensitivity in the guinea pig.

Delayed type skin reactions in guinea pigs have been assessed by measuring three parameters: increase in skin thickness, diameter of erythema and intensity of erythema. Some groups of animals were immunized with different protein antigens in Freund's complete adjuvant with or without cyclophosphamide (CY) pretreatment; others received a single high dose of antigen intravenously at the time of immunization. The results emphasize the importance of measuring all three parameters for several days after skin testing. The intensity or erythema was found to be an especially useful parameter for assessing CY-induced modification of delayed hypersensitivity (DH) reactions. The increase in skin thickness, which can be measured objectively, was also valuable as both immediate and DH reactions are characterized by induration. The diameter of erythema could only be measured accurately for a short time after skin testing. Furthermore, the effects of intravenous antigen and CY pretreatment were not reflected by that parameter.

Animals↗
PubMed1977

The relation between B-cell stimulation and delayed hypersensitivity. The effect of cyclophosphamide pretreatment on antibody production.

Cyclophosphamide (CY), which can enhance some forms of delayed-type hypersensitivity if given 3 days before immunization, is also a potent suppressor of most antibody mediated 4-h skin reactions to protein antigens. However many haemagglutinating antibodies, which are present in serum at the time of skin testing, are not similarly suppressed. Antibody titres in some sera recovered from CY-pretreated guinea-pigs differ little from titres in control sera. This resistance to CY suggests that long-lived precursors characterize the B-cell lines that produce many haemagglutinating antibodies, whereas the CY-sensitive precursors of skin reactive antibodies, which mediate Arthus-type reactions, are probably rapidly dividing, short-lived cells. Furthermore, the novel appearance of BGG antibodies in sera from CY-pretreated animals immunized with DNP50-BGG indicates that haemagglutinating antibody responses to some antigens are regulated by CY-sensitive mechanisms.

Animals↗
PubMed1977

The relation of immune depression and B-cell stimulation during the development of delayed hypersensitivity to soluble antigens.

A comparison has been made of the effects of cyclophosphamide (CY) pretreatment and i.v. injection of a high dose of antigen on delayed hypersensitivity induced by proteins in Freund's incomplete and complete adjuvants. Five antigens have been studied: obalbumin (OA), bovine serum albumin (BSA) bovine gammaglobulin (BGG), DNP 5-BGG and DNP 50-BGG. A spectrum of reactivity has been detected depending upon the ability of the antigen to stimulate B-cell as well as T-cell activity. Bovine serum albumin and BGG behave as relatively weak antigens in which the T-cell response, measured by delayed hypersensityity, is easily suppressed by i.v. antigen and the B-cell modulating system, revealed by CY sensitivity, is poorly stimulated. These proteins, injected i.v., are weak stimulators of antibody-dependent Arthus reactions. On the other hand, OA, DNP 5-BGG and DNP 50-BGG behave as strong antigens, resisting suppression of the T-cell response by soluble antigen and exhibiting (in Freund's incomplete adjuvant) a strongly developed CY sensitive, B-cell modulating system. Strong Arthus reactivity is readily demonstrated following i.v. administration of these antigens. A dissociation has been demonstrated between B-cell modulation of T-cell function and unresponsiveness induced by i.v. antigen. The failure to reverse the latter type of unresponsiveness by cyclophosphamide pretreatment suggests that separate mechanisms are involved in these systems.

Animals↗
PubMed1977

The organization of lymphoid tissue in relation to function.

Organized lymphoid tissue is found in the thymus, spleen, lymph nodes; lining the respiratory and alimentary tracts; and also occurring at sites of chronic inflammation. Apart from the thymus which is involved in the regulation of T-cell function, the other tissues are organized into T-cell and B-cell areas. Lymphocytes in T-cell areas respond by proliferation in cell-mediated immunity and by the production of suppressor cells and helper for antibody formation. B-cell areas are involved in the humoral antibody response. B-cells are segregated into lymph follicles where they form germinal centers and are found at the corticomedullary junction where they differentiate into plasma cells. The role of lymph follicles in becoming germinal centers is poorly understood, but these areas are known to be the site of antigen trapping in primed animals. The particular function of the spleen as a localized area of lymphoid tissue along the course of the blood vascular system is discussed, particularly with respect to its ability to respond to soluble antigen released from sites of localized antigen deposition such as tumors.

Antibody Formation↗
PubMed1977

Comparison of allergic aspermatogenesis with that induced by vasectomy. II. In vitro studies of cell-mediated immunity to sperm after vasectomy in man and guinea-pig.

Transformation of peripheral blood leucocytes was shown to be a valid assay for cell-mediated immunity to sperm in male guinea-pigs immunized with homologous epididymal sperm (ES) in FCA. A heat-treated extract of ES (BES) was used for culture. Possible developement of cell-mediated immunity to sperm after vasectomy was investigated in patients and guinea-pigs, by culture of blood leucocytes before and at intervals after operation. Patients' leucocytes were cultured with a heat-treated extract of human seminal sperm (BHS); guinea-pigs' leucocytes were cultured with BES. These cultures showed no evidence of specific stimulation of leucocytes by sperm extract, up to 1 year after vasectomy in patients, or up to 6 months in guinea-pigs. Similarly, no evidence of delayed hypersensitivity could be demonstrated by skin tests with BES in animals vasectomized 1 year previously. We consider that this study establishes that cell-mediated immunity to sperm does not develop in either man or guinea-pigs, up to 1 year after conventional vasectomy.

Animals↗
PubMed1976

Mediation of macrophage effector function by lymphokine.

The progressive effect of lymphokine contact on macrophages in vitro has been studied using various quantitative cytochemical techniques. Changes in the physiology of the macrophages have been seen rapidly after lymphokine contact. These appear to correlate with the functional effect of inhibition of migration. After more prolonged contact with lymphokine however, the macrophages exhibit different changes to their physiology and reach a state of enhanced cytochemical activity which has been termed 'activation'. By comparing the rapid effect of lymphokine to the changes seen after prolonged contact it is suggested that one can rationalize the apparent paradoxical effects of these soluble mediators which appear initially to 'turn off' the macrophage and subsequently 'activate' the same cell. In doing so an hypothesis is put forward as to how this mediator might work in vivo.

Animals↗