concanavalin-a and Thyroiditis

CD7 and CD28 are T cell Ig superfamily molecules that share common signaling mechanisms. To determine roles CD7 and CD28 might play in peripheral lymphocyte development and function, we have generated CD7/CD28-double-deficient mice. CD7- and CD28-single-deficient and CD7/CD28-double-deficient mice had normal levels of CD4 and CD8-single-positive T cells in thymus and spleen. However, CD28-deficient mice had decreased CD4+CD25+ T cells in spleen compared with wild-type mice, and CD7/CD28-double-deficient mice had decreased numbers of CD4+CD25+ T cells in both thymus and spleen compared with both wild-type and CD28-deficient mice. Functional studies demonstrated that CD4+CD25+ T cells from CD28-deficient and CD7/CD28-double-deficient mice could mediate suppression of CD3 mAb activation of CD4+CD25- wild-type T cells, but were less potent than wild-type CD4+CD25+ T regulatory cells. Thyroiditis developed in aged CD7/CD28-double-deficient mice (>1 year) that was not seen in age-matched control mice or single CD7- or CD28-deficient mice, thus suggesting in vivo loss of T regulatory cells allowed for the development of spontaneous thyroiditis. Taken together, these data demonstrated collaborative roles for both CD7 and CD28 in determination of number and function of CD4+CD25+ T regulatory cells in the thymus and peripheral immune sites and in the development of spontaneous thyroiditis.

Topics: Aging; Animals; Antibodies, Monoclonal; Antigen-Presenting Cells; Antigens, CD; Antigens, CD7; B7-1 Antigen; B7-2 Antigen; CD28 Antigens; CD3 Complex; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cell Division; Concanavalin A; Cytokines; Down-Regulation; Homeostasis; Immunophenotyping; Leukocyte Count; Lipopolysaccharides; Lymphocyte Count; Lymphopenia; Male; Membrane Glycoproteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Receptors, Interleukin-2; Spleen; T-Lymphocyte Subsets; Thymus Gland; Thyroiditis

Cytokines modulate the course of autoimmunity, but their role in the evolution of spontaneous disease is unclear. This study compared the cytokine kinetics of T cell cultures from thyroiditis (LT)-prone NB line BB/Wor rats with those of Wistar (Wis) rat controls following activation with the thyroid-specific antigen thyroglobulin (Tg) or Concanavalin A (Con A).. T cell enhanced splenocytes from 60 day old Wis and NB rats were activated with 0.5 microg/ml rat thyroglobulin (Tg) or Con A in the presence of homologous irradiated splenocytes as antigen presenting cells (APC's). In addition, the effect of APC's was determined in a crisscross experiment which examined NB T cell responses to Con A in the presence of Wis APC's. ELISA and RT-PCR were used to examine IL-2, IL-4, IL-10, TNFalpha, IFNgamma, IL-I0 concentrations and mRNA expression in the supernatant and cells from parallel cultures harvested at specific intervals. Frozen thyroids from 60 day old NB, Wis and Fisher rats were examined for the presence of IL-10 by immunohistochemistry. T cell proliferation was measured by 3H thymidine uptake.. Following activation with either Tg or Con A, IL-10 concentrations exceeded IFNgamma in NB rat cultures, but IFNgamma exceeded IL-10 in Wis cultures. Wis splenocytes significantly enhanced NB T cell proliferation and cytokine responses to Con A. Thyroids from 60 day NB rats contained IL-10, but no IFNgamma. There was no IL-10 in thyroids from Wistar or Fisher rats.. Splenocyte responses in LT-prone BB/Wor rats favor IL-10 production. Future investigations will examine the source of intrathyroidal IL-10 and its role in LT.

Topics: Animals; Cells, Cultured; Concanavalin A; Immunoenzyme Techniques; Interferon-gamma; Interleukin-10; Interleukin-2; Interleukin-4; Kinetics; Lymphocyte Activation; Mitogens; Rats; Rats, Inbred BB; Rats, Wistar; T-Lymphocytes; Thyroiditis; Tumor Necrosis Factor-alpha

The effect of age on the ability to elicit the various immune functions comprising experimental autoimmune thyroiditis in mice has been examined. Compared with young mice (2 to 3 mo), CBA/CaJ and A/J aged mice (20 to 30 mo) show a drastic reduction in their ability to develop circulating antibody after injection of mouse thyroglobulin (MTg) or mouse thyroid extract (MTE) in complete Freund's adjuvant (CFA). Delayed-type hypersensitivity responses were also depressed, as well as the ability of aged lymph node cells to proliferate in vitro to antigen and the ability of aged splenic T cells to function as helper cells for in vitro antibody production. However, after injection of these thyroid antigens in CFA, aged mice developed thyroid lesions either comparable to or only slightly less intense than those observed in young mice. The disparity between the levels of immune responses and thyroid lesions observed in aged mice can be explained by the greater susceptibility of aged thyroids to tissue damage, since transfer of identical numbers of Con A-activated MTE-primed young splenocytes to young and aged recipients results in a more severe thyroiditis in the aged recipients. Priming mice to MTE in CFA at 9 mo of age, at which time mice are responsive to MTE, did not enhance either T or B cell responsiveness to injection of MTE in CFA at 24 mo of age. Lymphocytes from MTE-injected aged mice also failed to transfer thyroiditis to young recipients after in vitro activation of the lymphocytes with Con A.

Topics: Aging; Animals; Autoantibodies; Autoimmune Diseases; Concanavalin A; Female; Lymphocyte Activation; Mice; Mice, Inbred A; Mice, Inbred CBA; Spleen; T-Lymphocytes; Thyroglobulin; Thyroiditis

Induction of autoimmune thyroiditis in normal syngeneic CBA/J mice was achieved by injection of 72-hr concanavalin A (Con A)-induced lymphoblasts from donor mice which had been immunized with mouse thyroglobulin (MTg) emulsified with complete Freund's adjuvant (CFA). Injection of lymph node or spleen cells, or frequent injection of serum taken from mice with autoimmune thyroiditis failed to transfer appreciable thyroiditis to recipient mice. Selection by treatment of incubated cells with monoclonal antibody and complement revealed that effector cells in Con A-induced lymphoblast populations for the transfer of autoimmune thyroiditis were Thy-1.2+, Lyt-1.1+, and Lyt-2.1- lymphocytes. These results demonstrate that experimental autoimmune thyroiditis can be adoptively transferred into naive mice by activated Thy-1+, Lyt-2- lymphoblasts.

Topics: Animals; Autoimmune Diseases; Concanavalin A; Female; Immunization, Passive; Lymphocyte Activation; Mice; Mice, Inbred CBA; T-Lymphocytes; Thyroglobulin; Thyroiditis

The mitogenic response to Con A and the production of T cell growth factor or interleukin 2 (IL 2) by splenic and peripheral blood lymphocytes of obese strain (OS) chickens with spontaneous autoimmune thyroiditis have been investigated. By using an optimized method with Con A-coated chicken erythrocytes (MRC), lymphocytes of OS chickens were found to exhibit significantly elevated mitogenic responses as compared with cells from either Normal White Leghorn chickens (NWL) or animals of the Cornell C-Strain (CS), from which the OS has originally been developed. This difference was observed throughout ontogeny up to 15 mo of age, and was associated with increased levels of IL 2 activity in the culture supernatants. The elevated responsiveness of OS T lymphocytes was also found to be manifested in the expression of receptors for IL 2, because Con A-stimulated lymphocytes of OS birds were significantly more effective than those from normal controls in absorbing IL 2 activity from conditioned media (CM) of stimulated spleen cells. High concentrations of CM were suppressive in IL 2 assays, signaling the presence of an inhibitory factor(s) in addition to IL 2. An additional indication for defective immunoregulation was that CM from OS lymphocyte cultures showed significantly less of this suppressive activity in comparison with CM of normal (NWL and CS) lymphocyte cultures. Finally, the spontaneous uptake of 125IUdR of embryonic and early post hatching OS spleen lymphocytes was consistently and significantly enhanced. This difference, however, in contrast to the one observed in Con A responses, was found to decrease with age. The data are discussed in view of the contradictory results concerning T cell functions reported for several autoimmune states in mammals.

Topics: Aging; Animals; Autoimmune Diseases; Chick Embryo; Chickens; Concanavalin A; Erythrocytes; Female; Interleukin-2; Lymphocyte Activation; Lymphokines; Male; Receptors, Immunologic; Receptors, Interleukin-2; Spleen; Suppressor Factors, Immunologic; T-Lymphocytes; Thyroiditis

Total lymphoid irradiation (TLI) at doses of 2200 rads or greater prevented diabetes in susceptible BB/W rats. Two of 29 (7%) treated rats became diabetic compared with 23 of 39 (59%) controls (P less than 0.001). TLI did not, however, prevent insulitis or thyroiditis in nondiabetic rats, nor did it restore the depressed concanavalin-A responsiveness of BB rat lymphocytes. T-lymphocyte subset proportions were the same in both groups. TLI was associated with significant radiation-related mortality, and nondiabetic TLI-treated rats weighed significantly less than controls. We conclude that TLI is effective in the prevention of BB rat diabetes. However, TLI fails to correct the subclinical immunologic abnormalities of the model and is associated with significant morbidity.

Topics: Animals; Autoimmune Diseases; Concanavalin A; Diabetes Mellitus, Type 1; Dose-Response Relationship, Radiation; Female; Islets of Langerhans; Lymphoid Tissue; Male; Mitosis; Pancreatitis; Rats; T-Lymphocytes; Thyroiditis

Ten inbred strains of rats were immunized with crude homologous thyroglobulin emulsified in Freund's complete adjuvant in order to investigate strain susceptibility to the induction of both thyroiditis and antibody to thyroglobulin. Two strains (LH and AUG) were found to be extremely susceptible and had 100% incidence of thyroid lesions which in general varied from moderate to very severe (mean index of pathology+/-SE, 2-5+/-0-2 and 2-1+/-0-4 respectively). One other strain (HL) also had 100% incidence of lesions but there were consistently mild in character (1-1+/-0-1). Two strains (DA and SD) were variable, with thyroid change varying from negative to severe. Three strains (LEW, WAG and PVG/c) had occasional lesions and the remaining two strains (AS and CAM) showed no thyroid change. Four strains (LH, AUG, HL and DA) consistently produced good antibody responses to thyroglobulin (mean titres+/-SE 7-3+/-0-3, 9-5+/-0-4, 6-9+/-0-3 and 6-6+/-0-5 respectively). In contrast WAG and CAM rats failed to develop autoantibody and the responses of AS, PVG/c and SD strain rats were quite variable. Although the autoantibody response generally correlated well with the presence of thyroiditis in a particular strain, LEW, AS and PVG/c rats often had good antibody levels with minimal thyroid lesions. Females of the most susceptible strains (LH and AUG) were found to have significantly more severe thyroid lesions and higher antibody titres to thyroglobulin than males. The most susceptible strains were all found to be of the Ag-B5 major histocompatibility genotype whilst the least susceptible were of the Ag-B2 genotype. However, wide interstrain variability was noted within the Ag-B5 genotype particularly with respect to the induction and extent of thyroid lesions. It was not found possible to relate the divergence in susceptibility between rat strains of Ag-B5 and Ag-B2 genotypes to differences in respective numbers of thyroglobulin-binding cells within the circulation of the non-immunized animal. Similarly, there were no differences in response between a susceptible (LH) and non-susceptible (CAM) strain to the phytomitogens PHA and Con A.

Topics: Animals; Antibody Formation; Antigen-Antibody Reactions; Autoantibodies; Binding Sites, Antibody; Concanavalin A; Female; Genotype; Hemagglutination Tests; Histocompatibility Antigens; Lectins; Lymphocyte Activation; Male; Rats; Rats, Inbred Strains; Sex Factors; Species Specificity; T-Lymphocytes; Thyroglobulin; Thyroid Gland; Thyroiditis

Topics: Animals; Antimycin A; Concanavalin A; Cytotoxicity Tests, Immunologic; Erythrocytes; Freund's Adjuvant; Guinea Pigs; Hemolysis; Immunoelectrophoresis; Immunoglobulin G; Lymphocytes; Male; Spleen; Thyroglobulin; Thyroiditis