bromochloroacetic-acid and Immunologic-Deficiency-Syndromes

The thymus provides the necessary microenvironments for the differentiation of T lymphocytes. Thymic non-lymphoid cells, such as epithelial cells, macrophages and interdigitating cells are thought to promote sequential stages in T cell differentiation. However, their specific role in each step of T cell differentiation remains to be established. With the development of new monoclonal antibodies it has now become possible to characterize the different thymic stromal cell types. In this review, various aspects of thymic stromal cells and their functions in T cell differentiation are discussed, such as: (1) phenotypic analysis of stromal cells in situ; (2) the application of new "chimeric' monoclonal antibodies which "link' developing thymocytes and stromal cells; (3) perturbation of thymic microenvironments after cyclosporin-A treatment; (4) perturbation of thymic microenvironments in new transgenic mouse lines; (5) phenotypic analysis of in vitro growing stromal cell lines.

Topics: Animals; Antibodies, Monoclonal; Cyclosporine; Extracellular Matrix; Immunologic Deficiency Syndromes; Immunophenotyping; Keratins; Lymphocyte Activation; Mice; Mice, Transgenic; Thymus Gland; Thymus Hormones

The role of skin and thymic epithelium in the promotion of T-cell activation and maturation is currently an area of great interest. In thymus, epithelium is located in the cortex, medulla, and in medullary epithelial swirls called Hassall's bodies. During studies of antigens shared by skin and thymic epithelial cells, we produced a murine monoclonal antibody (RTE-21) raised against the rat thymic epithelial cell line, IT26R21, that identified an antigen present in terminally differentiated epithelium of normal human skin and thymus. In indirect immunofluorescence studies, antibody RTE-21 identified cytoplasmic granules located in the stratum granulosum of normal human skin, Hassall's bodies of human thymus, and in a subset of cells of the IT26R21 rat thymic epithelial cell line. Moreover, the granular reactivity pattern of antibody RTE-21 in the stratum granulosum could be extracted by 1 M potassium phosphate (1 M KPO4). A 1 M KPO4 extract of epidermis containing keratohyalin granule proteins was dialyzed against distilled water, solubilized in reduced sample buffer and subjected to polyacrylamide gel electrophoresis and Western immunoblot analysis. In this assay, antibody RTE-21 recognized proteins of 70, 36, 34, and 30 kDa. Using antibody RTE-21 and indirect immunofluorescence, we demonstrated that keratohyalin granules in human thymus were localized exclusively to Hassall's bodies. These data support the notion that human thymic Hassall's bodies result from terminal differentiation of medullary thymic epithelium. Thus, antibody RTE-21 should be an important probe for the study of skin and thymic epithelial cell maturation in vitro and in vivo.

Topics: Antibodies, Monoclonal; Antigens; Autoantigens; Cell Differentiation; Cytoplasmic Granules; Epithelial Cells; Epithelium; Humans; Immunologic Deficiency Syndromes; Keratins; Skin; Thymus Gland

Topics: Antibodies, Monoclonal; Antigens, Surface; HLA Antigens; Humans; Immunologic Deficiency Syndromes; Keratins; Lymphocytes; Thymus Gland

The human thymic microenvironment is important in promotion of T cell maturation, particularly during early stages of thymic ontogeny. Hassall's bodies (HB) are epithelial swirls in the human thymic medulla that are thought to be derived from endocrine medullary thymic epithelium. To study the ontogeny and function of various components of the human thymic microenvironment, we have produced four monoclonal antibodies (TE-8, TE-15, TE-16, and TE-19) that selectively reacted in thymus with HB. Antibodies TE-8 and TE-16 reacted with the cells forming the outer rim of the HB swirl. Antibody TE-19 reacted with the entire cellular portion of HB and with epithelial cells immediately surrounding HB. Granular foci in the cellular swirls of greater than 90% of HB reacted with antibody TE-15. During thymic ontogeny, the antigens defined by antibodies TE-8, TE-15, TE-16, and TE-19 were first detected in fetal thymus on HB beginning at 16 wk gestation, the age when HB morphologically appear in the thymus. Aberrant expression of the antigens corresponding to antibodies TE-8, TE-15, TE-16, and TE-19 was observed on thymic tissue from individuals with severe cellular immunodeficiency disease. In human skin, antibodies TE-8, TE-16, and TE-19 reacted with the stratum granulosum; antibody TE-15 reacted with the stratum corneum. Thus, with the use of antibodies TE-8, TE-15, TE-16, and TE-19, we have identified HB as antigenically distinct regions of endocrine thymic epithelium. Furthermore, we have shown that these anti-HB reagents also selectively react with epidermal keratinocytes in the terminal stages of keratinocyte maturation.

Topics: Animals; Antibodies, Monoclonal; Antigens, Surface; Cell Line; Child, Preschool; Female; Fluorescent Antibody Technique; Gestational Age; Humans; Hybridomas; Immunologic Deficiency Syndromes; Infant; Infant, Newborn; Keratins; Mice; Mice, Inbred BALB C; Pregnancy; Thymus Gland