Interleukin 2 and stimulator lymphoblastoid cells will induce human thymocytes to bind and kill K562 targets.

Human thymocytes cultured in the presence of IL-2 and an irradiated B cell line became cytotoxic to K562 target cells. Thymocytes cultured alone or with only IL-2 exhibited almost no killing, but thymocytes cultured in the presence of stimulator cells alone exhibited low levels of cytotoxic activity. Removal of Fc gamma receptor-bearing cells from the activated thymocyte population almost completely abolished the binding and lytic activity. Separation of thymocytes into Fc microns+ and Fc microns-cells before culturing with IL-2 and stimulator cells revealed that only the Fc microns+ subpopulation developed into K562 killer cells. These findings indicate that modulation of Fc microns to Fc gamma receptors on the thymocyte cell surface is part of the maturation process of this particular subset of cytotoxic cells. Morphologically, most of the activated Fc gamma+ K562-binding cells were large, granulated lymphocytes. Only very few of the round, nongranulated small thymocytes were bound to K562 target cells

Morphologic observations of human T and B lymphocytes by scanning electron microscopy

T cell concerned with cell mediated immunity and B cell concerned with humoral antibody are classified by scanning electron microscopy of the surface structure of lymphocytes using E binding lymphocytes and EAC (sensitized sheep erythrocytes treated with complement) binding lymphocytes. For the purpose to elucidate morphological differences between T cell and B cell the scanning electron microscope observations were carried out with the blast forming lymphocytes incubated in the presence of PHA. As a result it has been demonstrated that T cells have short microvilli on the cell surface, but the reason for the difference in the number of the microvilli is unclarified. Even T cells have sometimes long microvilli in the younger stage, they are longer and more slender than those of untreated peripheral B cells.</p

Early detection of disease program: Evaluation of the cellular immune response

Surfaces of normal, cultured, and mitogen-stimulated mouse lymphoid cells were examined by scanning electron microscopy (SEM). Lymphocytes with smooth, highly villous and intermediate surfaces were observed in cell suspensions from both spleens and thymuses of normal mice and from spleens of congenitally athymic (nude) mice. Several strain-specific surface features were noted, including the spine-like appearance of microvilli on C57B1/6 lymphocytes. Although thymus cell suspensions contained somewhat more smooth cells than did spleen cell preparations, lymphocyte derivation could not be inferred from SEM examination. Studies of cells stimulated with mitogenic agents for thymus-derived lymphocytes (concanavalin A) or for bone marrow-derived lymphocytes (lipopolysaccharide) suggested that, in the mouse, development of a complex villous surface is a general concomitant of lymphocyte activation and transformation

Comparative analysis of T and B-cell subpopulations in normal thymus and thymus of myasthenia gravis

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。A clinico-pathological investigation was performed, examining T and B-cell subpopulations of normal and myasthenia thymus. The proportion of T-cells in healthy human thymus was found to be high (96-99%), as detected by the cytotoxicity method using the antithymocyte serum plus complement (T-ATS). A second test, likewise, confirmed this with similar results, using the E-rosette method with SRBC (T-E). B-cells in healthy thymus were low (0-3%), when measured by the EAC-rosette method employing SRBC and anti-SRBC antibody with mouse complement. However, in tests on myasthenic thymus cells the proportion of T-cells was low (43-88%). On the other hand, B-cells were found to be significantly higher (10-35%) than for healthy thymus cells. Furthermore, the use of these two testing methods, i.e. T-E and T-ATS, provided a noticeable difference between their results in the total T-cell counts for each group. A further item of interest was detected by the dissociation between the proportion of T-ATS and T-E for myasthenic cells. In most cases, healthy thymus cells were sensitive to even the lowest concentrations of ATS (1 : 2, 408). On the other hand, some myasthenic thymus cells seem to have a low amount of thymic antigen, even at high concentrations, since they were not killed by higher dilutions of ATS. This tendency was similar for both cell samples collected from thymomatous and non-thymomatous areas of myasthenic patients

Viruses and the Conntective Tissue Diseases

A number of observations in the last few years have attracted attention to the possibility of viral infection in systemic lupus erythematosus (SLE). One of these is the occurrence of interwoven tubular structures, usually in the endothelial cells of the kidney but also in the lymphocytes and in fibroblasts when SLE skin fibroblasts are cultured. These tubular structures have resembled viruses (they were thought by their discoverers to be myxo- or paramyxoviruses), but it has been argued that they are not viruses because of their size and appearance and because they have been produced in tissue cultures from subjects who do not have SLE; they occur in many other conditions which are not related to SLE

Requirement for the coexpression of T3 and the T cell antigen receptor on a malignant human T cell line.

The association between T3 and the T cell antigen receptor was examined using the T3 bearing T cell leukemic line Jurkat. A monoclonal antibody, C305, was produced, which reacted with idiotypic-like determinants expressed on Jurkat. The molecule with which this antibody reacted was a disulfide-linked heterodimer of 90 kD, composed of polypeptides of 42 and 54 kD. Thus, C305 reacted with a molecule with characteristics of the putative T cell antigen receptor described by others. A series of mutants of Jurkat, induced with ethyl methane sulfonate or radiation, was selected for T3 or antigen receptor negativity. In every instance, there was a concomitant loss of both T3 and the antigen receptor as assessed by quantitative absorption, indirect immunofluorescence, and antibody plus complement-mediated cytotoxicity. The absence of antigen receptor molecules was confirmed on diagonal gels, excluding the possibility that conformational changes of the antigen receptor on such T3-negative mutants were responsible for the failure of such mutants to react with C305. Moreover, in a mutant that expressed a marked decrease in the level of T3 expression, there was a comparable decrease in the expression of antigen receptor determinants. These results suggest that there is an obligate requirement for the coexpression of T3 and the T cell antigen receptor. Furthermore, attempts to activate such mutants with the lectin phytohemagglutinin suggested that the expression of T3 and/or the antigen receptor was required for activation of these cells