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J E Ryser

Publications and source records attributed to J E Ryser.

30 records · Page 2Linked to original sources
PubMed1982

The area of attachment of cytotoxic T lymphocytes to their target cells shows high motility and polarization of actin, but not myosin.

Conjugates of cytotoxic T lymphocytes attached to their target cells were studied by double immunofluorescence on fixed smears to detect simultaneously the localization of actin and myosin within the cells. Actin was found to be polarized in the area of attachment of the lymphocytes (but not of the target cells), whereas myosin remained evenly distributed in the cytoplasm. When living conjugates were brought to 37 degrees C to induce cytotoxicity, this pattern remained unchanged, but observation by interference reflexion microcinematography revealed a high motility of the lymphocytes in the contact area. This localized motility in the area of attachment associated with a peculiar actin polarization, which has no equivalent in any type of cell contact presently known, could represent a necessary step in the sequence of events leading to target cell killing by cytotoxic T lymphocytes.

Actins↗
PubMed1979

Cell-mediated immunity to antigens associated with murine sarcoma virus-induced tumors: augmentation of cytolytic T lymphocyte activity by successive specific and nonspecific stimulation in vitro.

It has been shown previously that lymphoid cells from mice which have rejected a tumor induced by the Moloney sarcoma virus-leukemia virus (MSV-MLV) complex develop high levels of specific H-2-restricted cytolytic T lymphocyte (CTL) activity after in vitro stimulation with syngeneic, irradiated MLV-induced lymphoma cells in mixed leukocyte-tumor cell cultures (MLTC). Attempts to further increase lytic activity by restimulating long-term MLTC cells with syngeneic, irradiated lymphoma cells have met but with limited success. This report shows that, in contrast to the lack of increased activity observed after specific stimulation with lymphoma cells, nonspecific stimulation of long-term MLTC cells either with supernatants from secondary mixed leukocyte cultures (2 degrees MLC SN) or with supernatants from concanavalin A-stimulated spleen cells leads, on a per cell basis, to a further 5 to 10-fold increase in CTL activity. The stimulatory activity of 2 degrees MLC SN is due to a factor(s) of apparent mol. wt. of 25,000 to 40,000. The activity of the CTL populations formed under these conditions is at least 100-fold higher against syngeneic as compared to allogeneic MLV-induced or unrelated tumor cells.

Animals↗
PubMed1979

Limiting dilution analysis of alloantigen-reactive T lymphocytes. III. Effect of priming on precursor frequencies.

The effect of specific priming with alloantigens on the frequency of cytolytic T lymphocyte precursors (CTL-P) has been investigated. Alloimmune lymphoid cells were obtained from the spleen of C57BL/6 (H-2b) mice primed with DBA/2 (H-2d) tumor cells or from 14-day unidirectional mixed leukocyte cultures (C57BL/6 anti-DBA/2). CTL-P frequencies directed against H-2d alloantigens were estimated by limiting dilution analysis in a sensitive micro MLC system. Under these conditions, an apparent increase of 3 to 4-fold in CTL-P frequency was observed in alloimmune (as compared with normal) C57BL/6 spleen cells. Evidence was obtained suggesting that this increase was specific for the priming alloantigens. A much greater increase in CTL-P frequency (25 to 100-fold) was observed after alloimmunization of C57BL/6 spleen cells in unidirectional MLC. Under the latter conditions, 5 to 20% of the surviving splenic MLC cells could be identified operationally as CTL-P. A similar enrichment in CTL-P frequency was obtained when lymph node, peripheral blood, or thymus cells were cultured for 14 days in MLC. These studies provide direct evidence that the pool of specific CTL-P can be expanded after alloimmunization. Furthermore, the very high frequencies observed after in vitro priming indicate that this system should be particularly useful for future studies of the progeny of individual CTL-P.

Animals↗
PubMed1977

Mechanism of target cell lysis of cytolytic T lymphocytes. I. Characterization of specific lymphocyte-target cell conjugates separated by velocity sedimentation.

Differential velocity sedimentation was applied for separating alloimmune T lymphocytes bound to target cells (TC) from free lymphocytes. Maximal size differences between lymphocytes and TC were achieved a) by isolating the fraction of small peritoneal lymphocytes (SPL) from an alloimmune peritoneal cell population, and b) by selecting large tumor cells as TC. Under the conditions used, most of the conjugates formed at room temperature consisted of one SPL bound to one TC, and adequate separation of bound from free SPL could be achieved within less than 5 min. Functional studies of the conjugate-enriched fractions showed that a minimum of 60% of TC-bound SPL were indeed cytolytic. Conjugate-depleted fractions, however, were still lytic, suggesting that not all effector cells formed stable conjugates at room temperature. Transmission and scanning electron microscopy studies revealed that binding between SPL and TC was achieved through interpenetrating membrane projections and was characterized by point and broad zone contacts. When lysis was allowed to proceed, prominent changes of the TC membrane morphology, including loss of microvillous projections, appearance of localized blebs, pseudopod-like projections, and membrane defects were documented.

Animals↗
PubMed1977

The humoral immune response of mouse bone marrow lymphocytes in vitro.

Mouse bone marrow (BM) small lymphocytes are shown to contain competent precursors for a primary haemolytic plaque forming cell (PFC) response to heterologous red blood cells and TNP in an in vitro culture system. Their response is dependent on T co-operative factors, which can be provided by irradiated spleen cells activated by concanavalin A or the supernatant of an allogeneic culture, added at the beginning or after 24 h of culture. The frequency of PFC precursors for the response to SRBC is found to be equal or higher in BM than spleen cultures. However, BM lymphocyte cultures stimulated by E. coli lipopolysaccharide show an increase of DNA synthesis but contain only few polyclonal PFC, in contrast to spleen.

Animals↗
PubMed1972

Mouse thymus-independent and thymus-derived lymphoid cells. II. Ultrastructural studies.

The ultrastructural features of B-, T-, and surface Ig(sIg)-bearing cells have been studied on cell suspensions from lymphoid organs of mice at different stages of immunization. The cells were identified by exposure to rabbit antibodies against mouse-specific lymphocyte antigens (MSLA) or brain-associated theta antigen (BAtheta) for T cells, mouse-specific bone marrow-derived lymphocyte antigens (MBLA) for B cells, and mouse Ig for sIg-bearing cells. The rabbit antibodies fixed on the cell surfaces were detected by peroxidase-labeled sheep anti-rabbit Ig antibodies or by a "bridge" technique using southern bean mosaic virus or bacteriophage T4 as the final markers. In some experiments, short-lived lymphoid cells were labeled in vivo with repeated tritiated thymidine and the ultrastructural detection of their surface antigens was combined with radioautography. MBLA+ lymphoid cells showed a whole range of ultrastructural patterns. Most were small and medium-sized lymphocytes with a clear cytoplasm containing mono- and polyribosomes, but they comprised also blasts and large cells with various amounts of endoplasmic reticulum, as well as plasma cells at different stages of maturation. sIg-bearing cells appeared to be identical with MBLA+ cells, except that sIg was less easily detectable on large blasts, and only very rarely observed on plasma cells. MSLA+ and BAtheta+ cells fell into three categories. One of them (T(1) cells) consisted of small to medium-sized lymphocytes with a clear cytoplasm and few organelles, mostly monoribosomes. A second consisted of large cells (T(2) cells) characterized by numerous polyribosomes often in a "rosette"-like pattern, occasional dark, membrane-bound granules, and a developing "filamentous network." The third, very characteristic type, (T(3) cells) was represented by dark small to medium-sized lymphocytes, usually containing large amounts of closely packed ribosomes and showing a striking accumulation of filamentous network, often condensed in large areas devoid of cell organelles. This filamentous network appeared to correspond to the cytochalasin B-sensitive system of microfilaments found in other cells and considered to be one of the contractile elements of the cell. The T(3) lymphocytes showed frequently vesicles suggestive of a strong pinocytic activity, and assumed a variety of shapes, including uropods. Evidence is presented that T(1) lymphocytes represent "virgin" T cells, T(2) "activated," and T(3) "differentiated" lymphocytes.

Animals↗
PubMed1972

Mouse thymus-independent and thymus-derived lymphoid cells. I. Immunofluorescent and functional studies.

The simultaneous use on mouse lymphoid suspensions of heterologous antisera directed against thymus-derived (T) cell mouse-specific lymphocyte antigen and brain-associated theta antigen (MSLA and BAtheta) or thymus-independent (B) cell mouse-specific bone marrow-derived lymphocyte antigen (MBLA) surface antigens allowed direct proof of the different specificity of these antisera by double immunofluorescence (IF) staining with selective visualization of fluorochromes. These antisera and antisera against mouse Ig and its different types of chains were then used with technique of either double IF staining or IF combined with radioautography, allowing the following conclusions: (a) Surface Ig (sIg) was found exclusively on B cells and never on T cells, but not all B cells had sIg. Cells containing detectable amounts of Ig were MBLA+, but had less sIg than other B cells or none at all. There was evidence for the existence of a significant number of MBLA+ lymphocytes, neither bearing nor containing detectable Ig. (b) micro-Chains were the most frequent but not the only heavy chains found on spleen cells; however, it could not be decided with the technique used, if a single cell can bear more than one type of heavy chain. No cell containing gamma-chains was found to bear surface micro-chains, although a very few cells containing both micro- and gamma-chains were observed. (c) The antigen-binding cells detected after immunization with bacteriophage T4, bovine serum albumin, Maia squinado hemocyanin, and sheep erythrocytes were analyzed for MSLA, MBLA or sIg using double IF, a combination of IF and radioautography, or inhibition of "rosette" formation. Practically all the antigen-binding cells detected were MSLA-, MBLA+, sIg+. (d) More B cells than T cells were found among short-lived lymphoid cells labeled by repeated in vivo injections of tritiated thymidine, but the results did not support a simplified concept equating T cells to long-lived and B cells to short-lived lymphocytes. (e) Cells dividing rapidly in the lymph nodes draining the sites of immunization with various antigens were predominantly T cells 2 days after immunization and in majority B cells a few days later. (f) Incubation of lymphoid cells at 37 degrees C with rabbit anti-mouse Ig or anti-kappa chains led to complete disappearance of sIg and to decrease of MBLA ("antigenic modulation"). In the same conditions, anti-MBLA gave partial modulation of MBLA and of sIg; MBLA, however, reappeared much faster than sIg. No modulation of T cell surface antigens by the appropriate antisera was observed. Cell treatment with Pronase could remove MBLA, sIg, MSLA, and BAtheta, which reappeared within a few hours. Neuraminidase treatment was without detectable effect on these antigens.

Animals↗