Tissue-specific antigens

Phylogeny, Structure, Functions, and Role of AIRE in the Formation of T-Cell Subsets

It is well known that the most important feature of adaptive immunity is the specificity that provides highly precise recognition of the self, altered-self, and non-self. Due to the high specificity of antigen recognition, the adaptive immune system participates in the maintenance of genetic homeostasis, supports multicellularity, and protects an organism from different pathogens at a qualitatively different level than innate immunity. This seemingly simple property is based on millions of years of evolution that led to the formation of diversification mechanisms of antigen-recognizing receptors and later to the emergence of a system of presentation of the self and non-self antigens. The latter could have a crucial significance because the presentation of nearly complete diversity of auto-antigens in the thymus allows for the "calibration" of the forming repertoires of T-cells for the recognition of self, altered-self, and non-self antigens that are presented on the periphery. The central role in this process belongs to promiscuous gene expression by the thymic epithelial cells that express nearly the whole spectrum of proteins encoded in the genome, meanwhile maintaining their cellular identity. This complex mechanism requires strict control that is executed by several transcription factors. One of the most important of them is AIRE. This noncanonical transcription factor not only regulates the processes of differentiation and expression of peripheral tissue-specific antigens in the thymic medullar epithelial cells but also controls intercellular interactions in the thymus. Besides, it participates in an increase in the diversity and transfer of presented antigens and thus influences the formation of repertoires of maturing thymocytes. Due to these complex effects, AIRE is also called a transcriptional regulator. In this review, we briefly described the history of AIRE discovery, its structure, functions, and role in the formation of antigen-recognizing receptor repertoires, along with other transcription factors. We focused on the phylogenetic prerequisites for the development of modern adaptive immunity and emphasized the importance of the antigen presentation system.

Spontaneous (Hashimoto-like) chronic lymphocytic thyroiditis in a rhesus macaque (Macaca mulatta)

A case of a female, 10-year-old rhesus macaque (Macaca mulatta) with spontaneous chronic lymphocytic thyroiditis is presented. At necropsy, the thyroid gland was slightly enlarged, with up to 2 mm large, round, confluent, beige foci on the surface of both lobes. Histopathologic features resembled human Hashimoto's thyroiditis: multifocally, the interstitium was infiltrated by lymphocytes and variably sized lymphoid follicles. In the pituitary gland, there were increased numbers of large, basophilic cells throughout the adenohypophysis. Using a human electrochemiluminescence immunoassay (ECLIA), no autoantibodies against thyroglobulin, thyroid peroxidase, or thyroid-stimulating hormone receptor were detected.

Novel heterophile chicken antigen: immunohistochemical localization using antisera to Mycobacterium smegmatis and possible association with lymphocyte maturation

A novel heterophile antigen shared by Mycobacterium smegmatis and chicken tissues was demonstrated by the indirect immunoperoxidase method using antisera raised in rabbits immunized with a complete Freund's adjuvant containing killed Mycobacterium smegmatis as an immunostimulating component. This antigen was strongly expressed in medullary lymphocytes of the thymus and bursa of Fabricius, but was undetectable in lymphoid cells of the cortical regions of these organs. Only a few lymphocytes stained positively for the antigen in T- and B-cell areas of the spleen. These data suggest that the heterophile antigen is associated with the intrathymic and intrabursal maturation of chicken lymphocytes. The antigen was also detected in some nonlymphoid cells. It was not found in sheep erythrocytes, human and rat tissues or in killed bacillus Calmette--Guerin.

Localization of species cross-reactive epithelium and urothelium specific antigens in the urinary tract of the rat, mouse, hamster and guinea pig

Antiserum from a New Zealand white rabbit raised against the saline soluble fraction of calf bladder epithelium was absorbed to produce epithelial and urothelial specific stages. With indirect immunofluorescence antiepithelial antiserum reacted with all cell layers of the urothelium of a rat, mouse, hamster and guinea pig in all regions of the urinary tract, and in the epithelium of the renal pyramid and tubules. The most intense reaction in the urothelium was seen in the superficial cells of the rat and mouse but in the intermediate cells of the guinea pig. Urothelium specific antigens were demonstrated predominantly in the superficial cells of the urothelium as far as the fornix of the renal pelvis but not in the renal pyramids or tubules in all these rodents except for the guinea pig.

The brain and subarachnoid space as possible sites for endocrine tissue transplantation

Immunological rejection has been the major problem limiting the successful transplantation of tissue from one animal to another. Recent technological developments, combined with the use of the central nervous system as an immunologically privileged site, suggest that it might be possible to achieve long-term survival of hormone-secreting tissues, between two gentically dissimilar animals, if these tissues are transplanted to the brain and subarachnoid space of the host. The physiological parameters that should be considered in the clinical application of a transplant of this type are discussed.

Sequential studies in ankylosing spondylitis. Association of Klebsiella pneumoniae with active disease

A study of 163 patients with ankylosing spondylitis seen on 433 occasions showed that active inflammatory disease was strongly associated with the presence of Klebsiella pneumoniae in the faeces (P less than 0.001). Sequential studies showed that in patients with inactive disease the presence of a positive culture for Klebsiella was associated with the subsequent development of active inflammatory disease (P less than 0.001). These findings support the hypothesis that Kl. pneumoniae may be an initiating agent in ankylosing spondylitis.

Inhibition of leukocyte migration in agarose by KCl extracts of human melanoma cell line grown in serum-free medium

KCl extracts of Melanoma 14, a human melanoma cell line grown in chemically defined serum-free medium, inhibited leukocyte migration in 19/36 (53%) patients with malignant melanoma. Only 4/23 (17%) controls with non-melanoma malignancies and 4/25 (14%) normal subjects with no history of cancer were similarly inhibited. Only 2/27 melanoma patients tested against KCl extracts of normal muscle tissue excised from the donor of Melanoma 14 were significantly inhibited. Patients with Stage I (localized) melanoma and patients with Stage III (generalized) melanoma reacted with roughly equal frequency but the number of patients in each group was too small for meaningful statistical analysis. Leukocytes from the donor of Melanoma 14 were tested in a completely autologous system against extracts of Melanoma 14 tissue culture cells and extracts of autologous muscle and were specifically inhibited by the Melanoma 14 tissue culture extract (Migration Index = 0.67) but not by the extract of normal muscle (Migration Index = 0.96). Only 7/32 (22%) melanoma patients were significantly inhibited by an extract of non-melanoma tumor. These results suggest that melanoma-associated antigens are present in soluble extracts of this tumor line. Such extracts could provide a continuing source of standard melanoma-associated antigens for purification and chemical characterization and for diagnostic and prognostic tests in patients with malignant melanoma.

Identification of tissue-specific antigens and concanavalin A receptors on rat epidermal cells using a radio-immunoprecipitation method

Iodination with lactoperoxidase - 125I- - H2O2 was used to label surface components of rat epidermal cells. Lysis of the cells in non-idet P40 resulted in the solubilization of tissue-specific antigens and of concanavalin A receptors. These specificities were demonstrated using a radio-immunoprecipitation method. The tissue-specific antigens were recognized using absorbed rabbit anti-rat epidermal cell sera (Lloyd & Darnule 1974); they reacted with two low molecular weight components in the lysate (9,000 and 12,000 daltons). Concanavalin A reacted with three major components. Two had high molecular weights (75,000 and 95,000 daltons). The possibility that one of these components was radioiodinated lactooperoxidase, which would have reacted with concanavalin A, was disproved. Another component (which occasionally appeared as two peaks) was similar in size to the species detected by the tissue-specific antisera. Their non-identity was, however, demonstrated by the finding that the two specificities could be precipitated independently of each other.

Autologous immune complex nephritis induced with renal tubular antigen. II. The pathogenetic mechanism

The pathogenetic mechanism involved in a form of experimental allergic glomerulonephritis induced by immunization of rats with renal tubular antigen has been investigated. A single immunization with less than a milligram of a crude renal tubular preparation, probably containing less than 25 microg of the specific nephritogenic antigen, is effective in the induction of this form of chronic membranous glomerulonephritis. In the nephritic kidney autologous nephritogenic tubular antigen is found in the glomerular deposits along with gamma-globulin and complement. When large amounts of antigen are injected during induction of the disease the exogenous immunizing antigen can also be detected in the glomerular deposits. It appears that this disease results from the formation of circulating antibodies capable of reacting with autologous renal tubular antigen(s) and the deposition of these antibodies and antigen(s) plus complement apparently as immune complexes in the glomeruli. This pathogenetic system has been termed an autologous immune complex disease and the resultant glomerulonephritis has been similarly designated.