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54th Annual Meeting of the European-Association-for-the-Study-of-Diabetes (EASD), Berlin, GERMANY, OCT 01-05, 2018; International audience

The aim of the present study was to identify murine T-cell epitopes on pertussis toxin subunit S4. Six mouse strains with five different haplotypes at the H-2 locus were immunized with the pertussis toxin B oligomer. Lymph node lymphocytes were isolated and stimulated in an in vitro proliferation assay with pertussis toxin components and 11 overlapping synthetic peptides synthesized on the basis of the primary sequence of S4. In vitro proliferative responses to the synthetic peptides revealed the presence of four distinct murine T-cell epitopes on subunit S4. The recognition of the peptides was major histocompatibility complex restricted. Immunizing four of the six mouse strains with the synthetic peptides showed that the peptides which were demonstrated to contain T-cell epitopes following immunization with the B oligomer were able to induce proliferative responses to detoxified pertussis toxin and pertussis toxin components containing subunit S4. One of the identified murine T-cell epitopes corresponded to one of the major human T-cell epitopes previously identified on subunit S4. It is hoped that this murine model system will facilitate the development of a synthetic immunogen mimicking the protective properties of pertussis toxin.

Two small lymphocyte subpopulations from human peripheral blood were produced by rosette sedimentation procedures, and tested for in vitro functions by stimulation with mitogens, PPD and allogeneic lymphocytes, and for effector capacities in ADCC. The non-T, non-Fc subpopulation had previously been found to be a SmIg+ fraction which did not aquire new surface markers during unstimulated culture, did not respond to mitogens, PPD or allogeneic cells but were potent MLC stimulators. In addition, they were poor ADCC effector cells. The non-T, non-B ('Null') cells, which showed varying surface marker profiles from donor to donor, were able to respond to mitogens and PPD, but were weak MLC responders. Potent ADCC effector capacity was, however, found to be exhibited by this subpopulation.

Udgivelsesdato: 1982-Sep-1

Udgivelsesdato: 1979-Jan

Mononuclear cells from the blood of healthy normal humans were kept in cultures under nonstimulating conditions for 16 hr in the presence or absence of human interferon. The relative quantities of HLA antigens and beta(2)-microglobulin on the cultured cells were determined by quantitative immunofluorescence (fluorescence-activated cell sorter) and by the capacity of cells to absorb out cytotoxic antibodies against the relevant antigens. Interferons of different origin and purities enhanced the expression of HLA antigens and beta(2)-microglobulins, whereas membrane immunoglobulins and antigens recognized by antiserum raised against human brain and T cells were the same on interferon-treated and control cells. Similar interferon effects were observed on an Epstein-Barrvirus-negative Burkitt lymphoma cell line. The enhanced expression of histocompatibility antigen subsequent to intereferon treatment was observed on B- and T-enriched lymphocyte populations and was found to be dose dependent with the optimum with "physiological" concentrations of interferon. Pretreatment of lymphocytes with interferon for 2 hr was found to be as effective as having interferon present during the total culture period. The interferon-induced enhancement of antigen expression on cells was dependent on active protein synthesis. Udgivelsesdato: 1978-Dec

Normal human peripheral blood lymphocytes were incubated in the presence of different concentrations of interferon for various incubation periods. Subsequently, the amount of beta 2-Microglobulin and HLA-A, B and C surface antigens was estimated by means of quantitative immunofluorescence (flow cytofluorometry) and by a radioimmunoassay for beta 2-Microglobulin. It was found that the amounts of these MHC antigens increased in a dose and time-dependent way after interferon treatment. Furthermore, the influence of different temperatures on this IFN-induced increase in beta 2-Microglobulin was gradually enhanced after incubation at 37 degrees C to 39 degrees C incubation mostly suppressed the beta 2-Microglobulin increase observed at 39 degrees C. The total amount of membrane associated beta 2-Microglobulin was estimated by a radioimmunoassay. After interferon treatment a beta 2-Microglobulin increase was observed ranging from 39% to 122% in different experiments. It is shown that interferon is the substance responsible for the effects on lymphocytes reported here, because completely pure interferon-proteins had the same activity as has been shown for partially purified interferon preparations. Udgivelsesdato: 1981-null

The in vitro effect of two different glucocorticoids (prednisolone and dexamethasone) on the expression of beta 2-microglobulin and HLA-A-A, -B and -C-antigens on the surface of cultured lymphocytes was measured by quantitative immunofluorescence (flow cytofluorometry) and by a radioimmunoassay. Both antigens were found to be decreased, dexamethasone typically in a concentration of 10-6 mol/l causing a decrease in surface beta 2-microglobulin of 15% after an incubation period of 24 hr. The expression of two other lymphocyte surface antigens, Igm and Thy antigens, measured in parallel with beta 2-microglobulin and HLA antigens, was not affected by the same culture conditions. The steroid effect was not due to masking of the affected antigens, but was completely abolished by inhibition of protein synthesis. Udgivelsesdato: 1981-May

Udgivelsesdato: 1981-Mar-16

By means of simple rosette sedimentation methods two subsets from human peripheral blood lymphocytes have been isolated: (1) (E, Fc)- and (2) (E, Ig)-. The first subset was obtained by centrifuging suspensions of macrophage-depleted PBL in which E and EA rosettes had been allowed to form simultaneously. The dominant marker of these E- Fc- cells was surface Ig, and during 4 days of culture this population did not alter its surface markers. Subset 2 was obtained in two ways following rosette centrifugation with AET-treated SRBC and rabbit anti-human Ig-coated autologous RBC. This 'Null cell population' was shown to be highly variable as judged by the surface markers applied after 4 days of culture, and it is suggested that Null cells contain a number of immature lymphoid cells that may acquire their surface marker during culture. It is concluded that the methods described for purification of small subsets of human lymphocytes are effective and easy to perform and might be used to purify cells for functional studies. Udgivelsesdato: 1978-null

Four normal human donors were immunized with 2 mg of heat-killed Corynebacterium parvum by subcutaneous and intracutaneous injections, and lymphocyte surface markers, antibody-dependent (ADCC), and spontaneous cell-mediated (SCMC) cytotoxicities followed for a 28-day period. Although no changes were observed in the relative proportions of B, T, and Fc receptor-carrying lymphocytes, two T cell subpopulations, namely, the autologous rosette-forming cells and active rosette-forming cells, both exhibited significant increases. Significant increases were also demonstrated in the proportion of monocytes carrying Fc receptors and in the proportion of monocytes phagocytizing Latex beads. Although no consistent changes could be found in ADCC against the P 815 mastocytoma cell line, the SCMC against both the myeloid leukaemia line K 562 and the lymphoma line RAJI was found to be elevated as early as 6 hr post-vaccination. The possibility that the enhanced SCMC activity was induced in vivo by interferon was supported thus: 1) Enhancement of SCMC in vitro by interferon was abrogated by the vaccination. 2) Serum interferon determinations showed significant increases in parallel with the lack of in vitro SCMC enhancement.

Udgivelsesdato: 1986-null

E-rosette sedimentation with AET treated sheep red blood cells and human lymphocytes provieded a source of highly purified T- and non-T cells. Together with unseparated cells these were tested for responder and stimulator capacities in the mixed lymphocyte reaction, and it was found that the non-T cells were weak, but consistent responders only when T cells were present as stimulators. On the other hand, T-T combinations always exhibited weak proliferation demonstrating that T cells possess stimulator capacities. Adherent cells grown on Petri dishes were found to exert a dual function: as helper cells in low, and suppressor cells in high concentrations.