Adrian O. Vladutiu

Autoimmune murine thyroiditis relation to histocompatibility (H-2) type

Immunization of 33 inbred strains of mice with thyroid extract emulsified in complete Freunds adjuvant showed differences in both thyroid autoantibody response and autoimmune thyroid damage, related to the histocompatibility (H-2) type of the strain. Congenic mice of the same H-2 type exhibited the same pattern of antibody response and thyroiditis, regardless of the strains genetic background, thus showing a close relation between histocompatibility determinants and autoimmunity.

Inhibition of experimental autoimmune thyroiditis in mice by anti-I-A antibodies☆☆☆

Experimental autoimmune thyroiditis is induced in mice by immunization with thyroglobulin emulsified in Freunds complete adjuvant. The disease is characterized both by thyroid infiltration with mononuclear cells and by circulating thyroglobulin antibodies. The magnitude of the thyroid infiltration and the titer of thyroglobulin antibodies are controlled by genes in the I-A subregion of the major histocompatibility complex (H-2). We investigated the in vivo effect of monoclonal anti-Ia antibodies on experimental autoimmune thyroiditis in susceptible mice. Antibodies were given around the time of immunization, later after immunization, and to mice with established disease. Monoclonal antibody produced by the hybridoma line 10-3.6 (anti-I-Ak, s, u, v, z, f) completely prevented both production of thyroglobulin antibodies and thyroid infiltrates, when given shortly before or at the time of antigen administration. This effect was dose-dependent and this monoclonal antibody decreased the severity of the disease when given after the antigen challenge but did not fully suppress established thyroiditis. The same antibody markedly decreased the number of B lymphocytes in the spleen and decreased the thyroglobulin-induced spleen cell proliferation when either given in vivo or added in vitro to cell cultures. Antibodies produced by the hybridoma line 11.2.12 (anti-I-Ak) did not show an inhibitory effect on the disease. These experiments suggest that in this model of murine thyroiditis anti-Ia antibodies act on antigen-presenting cells. Furthermore, only one monoclonal antibody, anti-Ia, suppressed the immune response to thyroglobulin, suggesting a possible role for the isotype and specificity of anti-Ia antibody.

The severe combined immunodeficient (SCID) mouse as a model for the study of autoimmune diseases

There are no readily available in vivo models to study immune cells from humans with autoimmune diseases. SCID mice, which virtually lack both T and B lymphocytes and accept xenogeneic cells, have been used during the last 5 years to provide a milieu for lymphocytes isolated from individuals with various autoimmune diseases, or for lymphocytes from mice that have a systemic lupus erythematosus‐like syndrome. Whilst human autoantibodies to organ antigens have been demonstrated in most SCID mice engrafted with human lymphocytes from the peripheral blood or the target organ, inflammation of the mouse target organ has not generally been observed. This review critically analyses experiments in this area reported so far. Some pitfalls of the SCID mouse model of human autoimmune diseases are mentioned, and future experiments to study mouse and human autoimmunity with this model are proposed.

Fibroblast interferon treatment of a patient with chronic active hepatitis: Increased number of circulating T lymphocytes and elimination of rosette-inhibitory factor

A 23 year old woman with chronic active hepatitis documented by liver biopsy demonstrated persistent hepatitis B surface antigen, hepatitis B virus specific DNA polymerase hepatitis B core antigen (HBcAg), for approximately one year. The number of circulating T lymphocytes that rosetted with sheep erythrocytes was decreased, and a rosette-inhibitory factor was present in her peripheral blood. Interferon treatment (1 X 10(6) U/day intramuscularly for 82 days) resulted in a decrease of HBsAg and disappearance of HBcAg, (HBeAg) and specific DNA polymerase. In addition, the number of T lymphocytes increased to normal, and the rosette-inhibitory factor disappeared from the circulation. These findings suggest that the effect of interferon in chronic active hepatitis is mediated in part through its action on the immune system.

Detection of creatine kinase BB isoenzyme in sera of patients undergoing aortocoronary bypass surgery

Creatine kinase BB isoenzyme (CK-BB) was detected intraoperatively in 22 of 25 patients undergoing aortocoronary bypass surgery, both in the coronary sinus and in the mixed venous blood. In a group of 10 patients in whom selective intracavitary profound hypothermic arrest was used, CK-BB values were lower than in another group of 10 patients, in whom controlled ventricular fibrillation with moderate total body hypothermia was instituted. This latter group also had higher levels of CK-MB. Patients who developed acute myocardial infarction immediately prior to or during the surgical intervention had the highest CK-BB values. This enzyme appeared as early as 15 minutes after the institution of cardiopulmonary bypass and disappeared within 6 hours. It is considered that part of the BB isoenzyme in serum of patients undergoing heart surgery is of myocardial origin.

Experimental autoimmune thyroiditis in mice chronically treated from birth with anti-IgM antibodies

The role of T lymphocytes in the pathogenesis of experimental autoimmune thyroiditis in mice is well established while the role of B lymphocytes is unclear. Mice with thyroid lesions have thyroglobulin antibodies whereas these antibodies can occur in mice immunized with Tg that do not develop thyroid lesions. To determine whether thyroglobulin antibodies are necessary for the development of the thyroid infiltrates with mononuclear cells, which are characteristic for experimental autoimmune thyroiditis, AKR mice chronically treated from birth with goat anti-mouse IgM antibodies were immunized with mouse thyroglobulin in Freunds complete adjuvant when they were 7 weeks old. Control mice, similarly immunized, were chronically injected from birth with normal goat gamma-globulin. Three weeks after immunization, all mice were sacrificed, thyroglobulin antibodies in the serum were measured by hemagglutination assay and enzyme-linked immunosorbent assay, and thyroid pathology was assessed. The serum concentration of IgG and IgM, the percentage of B and T lymphocytes in the spleen (flow cytometry), and the in vitro proliferative response of spleen lymphocytes to stimulation by PHA, LPS, and Tg were also measured. All mice treated with anti-IgM antibodies did not have detectable thyroglobulin antibodies but 63% of these mice and 88% of control mice (all of which had thyroglobulin antibodies) had thyroid lesions. Mice treated with anti-IgM antibodies that did not have thyroid lesions had a more pronounced depression of B lymphocytes than similarly treated mice that had thyroid lesions. These experiments suggest that thyroglobulin antibodies are not necessary for the development of thyroid infiltrates with mononuclear cells. B lymphocytes could still participate in the production of experimental autoimmune thyroiditis by presenting thyroglobulin to helper T lymphocytes.

Estrogen receptor in uteri of mice of different H-2 genotypes.

A relationship between the amount of available estradiol receptors in uteri of inbred mice and theirH-2 genotype is suggested by study in congenic animals.

Purified human fibroblast interferon in vivo: skin reactions and effect on bone marrow precursor cells.

Human interferon from normal diploid fibroblasts, purified by sequential chromatography on concanavalin A-agarose and phenyl-sepharose, was administered parenterally in 4 subjects. Fever, marked skin hypersensitivity reactions and suppression of marrow stem cells (estimated by the count of myeloid colony-forming cells), side-effects common for less purified fibroblast and leukocyte interferons, were absent. Purified fibroblast interferon retained antiviral and immunomodulatory activity, evidenced by reduction of the blastogenic response of peripheral lymphocytes and decrease of hepatitis B virus markers in a patient with chronic hepatitis B infection treated with this substance.

Gene(S) at I-A Subregion Controls the Autoimmune Response to Thyroglobulin in Mice

Immunization of mice with thyroglobulin emulsified in Freunds complete adjuvant produces autoimmune thyroiditis, characterized by antibodies to thyroglobulin and infiltration of the thyroid with mononuclear cells. Some strains of mice are low and others are high responders to thyroglobulin. The immune response as reflected especially in the magnitude of the thyroid infiltration, is controlled by gene(s) within the H-2 locus. Previous attempts to map the Ir gene(s) for thyroglobulin (Ir-Tg) showed that it could be assigned to either the K or I-A subregion of H-2. An H-2 recombinant strain of mice, B10.MBR (H-2bq1), in which the H-2K is derived from the H-2b haplotype and which carries the I-Ak allele(s), was immunized with thyroglobulin. B10.MBR mice were high responders to thyroglobulin in contrast to C57BL/6 mice, which have both the H-2K and I-A from the H-2b haplotype and were low responders. This suggests that Ir-Tg, which controls the severity of autoimmune thyroiditis, maps within the I-A subregion, similar to gene(s) controlling the susceptibility to experimental myasthenia gravis.

Immunoradiometric assay of lipid A: a test for detecting and quantitating endotoxins of various origins

The ability to measure circulating endotoxin in various disease states has been hampered by the lack of a specific and quantitative assay. The test most commonly used has been the Limulus gelation assay, which measures an enzymatic effect of endotoxin rather than the substance itself. Based on a solid-phase immunoradiometric assay previously developed to detect the specific lipopolysaccharide from Escherichia coli 026, a similar assay has been developed for the lipid A moiety of endotoxins. The assay uses rabbit antibodies to lipid A which do not react with ketodeoxyoctonate, myristic or beta-hydroxymyristic acids, and detects lipid A obtained from endotoxins of various origins after acid hydrolysis of lipopolysaccharide. Experiments in rats given exogenous endotoxin suggest that this assay can be useful for quantitation of bacterial endotoxins in serum and for studying the pathophysiology of experimental endotoxemia.