Antibodies against common antigen of epithelial tissue of human thymus and skin epidermis in myasthenia gravis

Experiments by the indirect immunofluorescence method showed that the sera of patients with myasthenia gravis in a high percentage of cases react with cells of epithelial type of the human thymus. By absorption of the sera with suspensions of epidermal cells and tissue homogenates of several human organs it was shown that the antigen of the epithelial cells with which the sera of patients with myasthenia react belongs to the epidermal heteroorganic antigens of the thymus, i.e., it is common to the epithelium of the thymus and the epidermis of the human skin. The presence of antibodies against epithelial tissue cells of the thymus in the blood serum of patients with myasthenia gravis suggests that in this disease an immunopathological process takes place, aimed against thymus tissue antigens, including against the heteroorganic structures of its epithelium.Laboratory of Streptococcal Infections, N. F. Gamaleya Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR. Laboratory of Clinical Pathophysiology, Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR O. V. Baroyan.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 1, pp. 60–62, January, 1977.     

Cross-reacting thymus and brain antigens in the cerebral cortex

Rabbit antisera against antigens of whole mouse, rabbit, guinea pig, and human brain were found to have a cross cytotoxic action on lymphocytes of the thymus, lymph nodes, and spleen of the animals of these species. Mouse thymus cells were the most sensitive (index of cytotoxicity 63–100%); the cells of other mouse lymphoid organs and lymphocytes of the other species of animals and man were more resistant. Bone marrow cells were not injured by any serum. Antigens responsible for the cytotoxic properties of the sera were found to be located in the human cerebral cortex and to be absent from the white matter and the brain stem.Presented by Academician of the Academy of Medical Sciences of the USSR V. I. Ioffe.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 7, pp. 834–836, July, 1976.     

IL-6阳性细胞在小鼠胸腺内的定位

目的：检测IL－6阳性细胞在小鼠胸腺的分布。方法：采用免疫酶细胞化学，免疫荧光双染及免疫电镜技术方法原位显示小鼠胸腺不同部位IL－6阳性神经的表达情况。结果：光镜免疫酶组织化学确定了IL－6阳性细胞的分布范围，即IL－6在胸腺皮质和髓质的某些特定的细胞表达；进一步采用免疫荧光双染色及免疫电镜技术对IL－6阳性细胞进行了解析，确定了小鼠胸腺内IL－6阳性细胞主要是胸腺实质中不同形态的巨噬细胞，IL－6不存在于胸腺上皮细胞及胸腺细胞。结论：巨噬细胞是小鼠胸腺IL－6的主要来源，参与胸腺细胞发育微环境的构成。     

Androgen receptor in the human thymus

An androgen binding species has been identified in partially purified cytosol from human thymic tissue, resolved from sex steroid binding globulin by gel chromatography. This putative 5 alpha-dihydrotestosterone receptor was characterised by high affinity (Kd 6.7 X 10(-10) M) and low capacity (9 fmol/mg of cytosol protein). High affinity binding was confirmed with methyltrienolone (R1881). Competition studies were carried out with a number of androgenic compounds and 5 alpha-19 nordihydrotestosterone was shown to possess the highest affinity for the androgen receptor.     

Immunoglobulin-positive human spleen and thymus cells during embryogenesis

The relative percentages and types of luminescence of immunoglobulin-positive cells were investigated by the indirect immunofluorescence method in the spleen and thymus of 32 human fetuses between the 11th and 32nd weeks of development. The number of Ig-positive cells in the spleen increased during embryogenesis from 13 to 33.7%, but in the thymus it remained at 0–2% regardless of the stage of development of the fetus. For the first time a differential count of Ig-positive cells based on types of luminescence was carried out in the course of embryogenesis. Thymus cells had solitary points of luminescence on their surface. Lymphocytes with single, and later with multiple points, progressing to solid luminescence over the whole surface and, finally, cells with caps of luminescence appeared successively in the spleen during development of the fetus. The differences in the density of immunoglobulin receptors on the surface reflect the degree of differentiation of the lymphocyte.Laboratory of Embryonic Histogenesis, Research Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 1, pp. 38–40, January, 1980.     

Reconstructed human epidermis composed of keratinocytes, melanocytes and Langerhans cells

In addition to their basic biological interest, models of reconstructed epidermis provide useful tools for in vitro assessment of the toxicology and efficacy of new chemicals and drugs. The fact that the majority of these in vitro models are composed only of keratinocytes has excluded their use in the fields of skin pigmentation and immunology. After the successful introduction of functional melanocytes into the epidermal reconstruct, the integration of Langerhans cells remains an important challenge, particularly since after isolation of Langerhans cells from human epidermis, these cells cannot be subcultured and do not integrate into the reconstructing epidermis. The authors show that cord blood derived and CD34⁺ progenitors isolated from the peripheral blood give rise to residential Langerhans cells when co-seeded with normal human keratinocytes.     

Presence of eosinophilic precursors in the human thymus: Evidence for intra-thymic differentiation of cells in eosinophilic lineage

The distribution of myeloid cells in the human thymus was investigated by light and electron microscopy, immuno-histochemistry, andlor flow cytometry. A series of 74 thymic samples, from newborn to 37 year old patients, were studied. By light microscopy, aggregates of mononuclear cells were frequently present in intralobular septa and outer medulla. Among those cells, eosinophilic precursors (promyelocyte, myelocytes and metamyelocytes) were readily identified. These immature granular cells were present in all pre-invo-lutional thymi, and were particularly frequent in the thymi of patients who were younger than 5 years of age. The cells made up 30–50% of the total eosinophilic population and were frequently observed asagroupof cells at variousstages of differentiation, suggesting that they differentiate from preexisting precursors in the thymus. These eosinophilic precursors were mostly located in the intralobular septa and f ibroreticular network at the corticomedullary junction, while mature eosinophils were scattered throughout the thymus. Flow cytometric analyses, using stem cellenriched preparations, showed that cells expressing CD33 or CD34 constituted on average 2.55% and 3.33% (0.09% and 0.12% of the total cells), respectively. CD33+/CD34+ coexpressors were also identified, and they constituted 0.36% of the analyzed cells (0.01% of the total cells). No statistical difference in the proportions of CD33+ andlor 34' cells was noted between any age groups. It is concluded that eosinophilic precursors present in the thymus differentiate into cells in the eosinophilic lineage in particular areas such as the intralobular septa and f ibroreticular network of the outer medulla in pt'ein-volutional human thymi.     

Modulation of ABH histo-blood group antigen expression in normal and myasthenic human thymus

The role of ABH histo-blood group antigens (HBGA) in intercellular communication during normal and pathological processes is still uncertain. The present work investigates the expression of ABH HBGA in epithelial cells and lymphocytes in normal thymus, and characterizes the modulation of their immunoreactivity during myasthenic transformation. Immunohistochemistry and immunoelectron microscopy were applied on normal young thymus and on myasthenia gravis-associated thymomas and thymic hyperplasias. The Hassall's corpuscules in the thymus of young individuals were homogeneously stained for HBGA, while in hyperplastic glands only their central part was positive. Stromal epithelial cells permanently expressed HBGA in all tissue samples. In thymomas, mainly the lymphocytes in close proximity to antigen expressing epithelial cells were positive, while in the hyperplastic gland the most intensely stained lymphocytes were those within Hassall's corpuscules. Novel evidence for modulation of ABH antigen reactivity in normal and myasthenic human thymus is presented. It suggests that HBGA might participate in the regulation of the cross-talk in the thymocyte microenvironment throughout the ontogeny, as well as during the myasthenic transformation.     

剪接因子SC35在大鼠胸腺细胞内的定位

目的：观察剪接因子SC35在大鼠体内重要器官内分布情况。方法：采用免疫酶以及免疫电镜技术对剪接因子SC35从组织学分布到超微结构定位进行了系统研究。结果：胸腺内大部分细胞内含有SC35或SC35类蛋白，而在肝和肾内未发现有标记。金颗粒主要分布在细胞核的染色质间区和染色质周边及核仁的致密纤维组分区中。大自鼠胸腺细胞内的金颗粒密度为细胞核内33．05个/μm^2，核仁内21.77个／μm^2，细胞质内9．90个/μm^2，对照组细胞内则金颗粒极少或没有，而在肝和肾细胞内未见。结论：SC35或SC35类蛋白存在于大鼠胸腺内，而非肝和肾。     

人胸腺内Ghrelin的免疫组织化学定位

目的:观察Ghrelin在人胸腺的定位与分布,为深入探讨胸腺内Ghrelin的功能意义提供实验依据。方法:采用特异性抗Ghrelin血清,用免疫组织化学ABC法观察人胸腺内Ghrelin的定位与分布。结果:Ghrelin免疫反应阳性细胞在胸腺内分布广泛。胸腺皮质浅层的Ghrelin阳性细胞呈巨噬细胞形态特点;而皮髓质交界区有大量上皮性网状细胞呈Ghrelin免疫反应阳性;胸腺髓质内Ghrelin阳性信号主要定位于树突状细胞和上皮性网状细胞;胸腺小体呈Ghrelin免疫反应强阳性。结论:胸腺内Ghrelin分布广泛,定位于胸腺巨噬细胞、上皮性网状细胞、树突状细胞和胸腺小体。Ghrelin可能参与胸腺细胞分化和成熟的调节。     

Cytokeratin expression in normal human thymus at different ages

Subsets of thymic epithellal cells were examined Immuno-histochemically to determine whether or not their pheno-types change during thymic growth and at early involution in terms of cytokeratin (CK) expression. Five monoclonal antibodies specific for CK4, CK8, CK13, CK18 and CK19 were used and applied for 16 neonatal, three Infantile and one adult thymus speeimen, which had been obtained at autopsy, that were normal macroscopically and microscopicaily. CK4, CK8, CK13, CK18 and CK19 were expressed simultaneously in the cortex, medulla and subcapsular area with the exception of CK4, which showed expression on the adult thymus. Light and electron microscopy showed that CK8 and CK19 expression was overlapped. Thus, It was thought that CK8 and CK19 formed complexes in the cytoplasm of thymic epithelial cells. The Immunoreactivity to CK4, CK13 and CK18 were attenuated or disappeared In the subcapsular area during the early involution stage. Interestingly, two patterns of CK18 expression were observed in the neonatal and Infantile thymus tissues, which Indicated that the thymic microenvironment was changeable even under normal conditions.