scholarly journals Generation of cytotoxic T lymphocytes in vitro. IV. Functional activation of memory cells in the absence of DNA synthesis.

1975 ◽  
Vol 142 (3) ◽  
pp. 622-636 ◽  
Author(s):  
H R MacDonald ◽  
B Sordat ◽  
J C Cerottini ◽  
K T Brunner
Keyword(s):  
T Lymphocytes ◽  
Dna Synthesis ◽  
Cell Number ◽  
Primary Response ◽  
Precursor Cells ◽  
Lymphoid Cells ◽  
Velocity Sedimentation ◽  
Secondary Response ◽  
Ctl Activity

Re-exposure of day 14 mixed leukocyte culture (MLC) cells to the original stimulating alloantigens (secondary response) has previously been shown to result in significant proliferation and in rapid reappearance of high levels of cytolytic T-lymphocyte (CTL) activity within the next 4 days. Moreover, evidence has been presented that CTL precursor cells in day 14 MLC populations, while they derived from cells were large at peak of the primary response (day 4) were themselves small lymphocytes which developed into large CTL after restimulation. In this study, inhibition of DNA synthesis by cytosine arabinoside (ARA-C) was used to investigate whether CTL formation could be dissociated from proliferation during the secondary response. It was found that within the first 24 h after restimulation (a) CTL activity increased 6-to-20-fold, (b) 60-70% of the small T lymphocytes became medium- to large-sized cells, and (c) both events were independent of DNA synthesis. By using two successive cell separations by velocity sedimentation at unit gravity, before and after stimulation of day 14 MLC cells for 24 h in the presence or absence of ARA-C, direct evidence was obtained that small CTL precursor cells developed into large CTL, irrespective of DNA synthesis. The presence of ARA-C for periods longer than 24 h inhibited any further increase in CTL activity, in contrast to a parallel increase in lytic activity and cell number from day 1 to day 4 in control restimulated cultures. Taken together with the finding that 90% of the medium- and large-sized lymphoid cells in control restimulated cultures underwent DNA synthesis within 24 h, these results thus suggest that during a secondary MLC response there is initially a differentiation step leading to the formation of CTL which, although it can be clearly dissociated from DNA synthesis, is under normal conditions followed by proliferation of these effector cells.

scholarly journals GENERATION OF CYTOTOXIC T LYMPHOCYTES IN VITRO

1974 ◽  
Vol 140 (3) ◽  
pp. 718-730 ◽  
Author(s):  
H. Robson MacDonald ◽  
Howard D. Engers ◽  
Jean-Charles Cerottini ◽  
K. Theodor Brunner
Keyword(s):  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Primary Response ◽  
Target Cells ◽  
Spleen Cells ◽  
Response Curves ◽  
Specific Cytotoxicity ◽  
Allogeneic Stimulation ◽  
Ctl Activity

Mouse cytotoxic T lymphocytes (CTL) were generated in unidirectional mixed leukocyte cultures (MLC) using normal C57BL/6 spleen cells as responding cells and irradiated DBA/2 spleen cells as stimulating cells. Cytotoxicity was assayed on 51Cr-labeled P-815 (DBA/2) target cells, and the relative frequency of CTL in individual cell populations was estimated from dose-response curves. Upon inclusion of 2-mercaptoethanol in the culture medium, it was found that significant CTL activity could be detected for as long as 3 wk in primary MLC. Reexposure of MLC cells to the original stimulating alloantigens after 14–41 days in culture resulted in significant cell proliferation and rapid regeneration of high levels of immunologically specific cytotoxicity. CTL activity in these secondary cultures increased dramatically within the first 24 h and reached higher peak levels than those found at the peak of the primary response. Furthermore, proliferation and reappearance of CTL activity could be demonstrated following each of as many as four sequential alloantigenic stimulations of the same initial cell population at 20-day intervals. Interestingly, cells recovered from MLC at the peak of the primary response on day 4 were insensitive to further allogeneic stimulation. Taken together, these results are consistent with the hypothesis that CTL differentiate in MLC to become long-lived memory cells which gradually lose their cytotoxic activity. Upon reexposure to specific alloantigen, such memory CTL rapidly regain their functional activity and proliferate to generate an expanded CTL population.

scholarly journals Immunological T-cell memory in the in vitro-induced experimental autoimmune orchitis: specificity of the reaction and tissue distribution of the autoantigens.

1978 ◽  
Vol 147 (1) ◽  
pp. 233-250 ◽  
Author(s):  
H Wekerle
Keyword(s):  
T Lymphocytes ◽  
Lymphoid Cells ◽  
Secondary Response ◽  
Mhc Antigens ◽  
Organ Specific ◽  
Normal Rat ◽  
Blast Cells ◽  
Autoimmune Orchitis ◽  
Experimental Autoimmune

Immunological memory has been induced in vitro against testicular autoantigens by priming normal rat T lymphocytes against autologous testis cells, and by permitting the isolated blast cells to revert back to small secondary lymphocytes (secondary EAO cells) in the absence of the priming antigen. The secondary EAO cells vigorously respond in a secondary response when reconfronted with syngeneic testis or lymphoid cells. Their responsiveness to nonself stimulator cells is, however, reduced. Secondary cells derived from concanavalin A-stimulated blasts, do not show that pattern of specificity. The specificity of the secondary EAO cells is definite, and cannot be affected by further culture on allogeneic fibroblasts, which are antigenic for unprimed T lymphocytes. At least part of the autoantigens are determined by the major histocompatibility gene complex (MHC). Factors provided by the culture system do not appear to determine the specificity of this reaction. Only minor cell populations can restimulate secondary EAO cells. One of these populations is presumably phage-like cells within the lymphoid populations can elicit a secondary EAO response. Thus, the autoantigens relevant in the secondary EAO response are either MHC antigens restricted to these testicular and lymphoid subpopulations, or MHC antigens recognized in conjunction with organ-specific non-MHC determinants.

scholarly journals Pre-emption of human cell-mediated lympholysis by a suppressive mechanism activated in mixed lymphocyte cultures

1975 ◽  
Vol 142 (6) ◽  
pp. 1606-1611 ◽  
Author(s):  
PM Sondel ◽  
MW Jacobson ◽  
FH Bach
Keyword(s):  
T Cell ◽  
T Lymphocytes ◽  
Positive Selection ◽  
Cytotoxic T Lymphocytes ◽  
Third Party ◽  
Velocity Sedimentation ◽  
Secondary Response ◽  
Suppressor Activity ◽  
Suppressor Mechanism

The regulation of B-cell and T-cell immune responses has been extensively examined and in the experimental animal appears to involve regulatory or suppressor T cells (1-4). The limitations of in vitro experimentation have made comparable study of nonpathological human suppression quite difficult (5). We report here an in vitro method that generates and quantitates suppressor activity in man after antigen-specific activation in mixed leukocyte culture (MLC). The one-way MLC induces both a proliferative response (6) and the generation of cytotoxic T lymphocytes (CTLs) (7). Both of these responses are mediated by antigen-specific T-cell subpopulations (8,9) and have been correlated with recognitive and destructive phases of allograft rejection. Recent reports have examined the antigen reactivity of mouse (10,11), rat (12), or human (13,14) lymphocytes obtained after proliferation in MLC. In all cases, after the primary MLC proliferative peak, the recovered lymphocytes rapidly differentiate upon re-exposure to the initial stimulating population, but do so only weakly when exposed to a presumably noncross-reactive third-party stimulating population. Velocity sedimentation separation studies have shown that the blast cells produced in a primary MLC revert to small lymphocytes that rapidly differentiate into proliferating and/or cytotoxic T lymphocytes upon restimulation with the initial antigen (15). These findings demonstrate that positive selection for the responding population in primary MLC does exist and may account for at least part of the specificity of the secondary response. However, this positive selection does not preclude possible involvement of a suppressor mechanism. In fact we have detected suppressor activity in primary MLC sensitization cultures at a time when the proliferation responsible for positive selection does not preclude possible involvement of a suppressor mechanism. In fact we have detected suppressor activity in primary MLC sensitization cultures at a time when the proliferation responsible for positive selection in not yet significant, suggesting that suppression may be overriding importance in the specificity of MLC-activated secondary responses.

scholarly journals Primary generation of cytolytic T lymphocytes in the absence of DNA synthesis.

1979 ◽  
Vol 150 (1) ◽  
pp. 196-201 ◽  
Author(s):  
H R MacDonald ◽  
R K Less
Keyword(s):  
T Lymphocytes ◽  
Dna Synthesis ◽  
Cytolytic Activity ◽  
Target Cells ◽  
Cytolytic T Lymphocytes ◽  
Spleen Cells ◽  
Con A ◽  
A Cell ◽  
Stimulation Of

The requirement for DNA synthesis during the primary differentiation of cytolytic T lymphocytes (CTL) had been investigated. CTL were induced polyclonally in vitro by stimulation of normal C57BL/6 spleen cells with concanavalin A (Con A)and their cytolytic activity was tested against 51Cr-labeled target cells in the presence of Bacto Phytohemagglutinin M. With this system, CTL activity could first be detected 48 h after exposure of spleen cells to Con A. Addition of cytosine arabinoside at concentrations sufficient to reduce DNA synthesis by 95-98% in Con A-stimulated cultures did not significantly inhibit the generation of cytolytic activity on a cell-to-cell basis. These results demonstrate that derepression of the genetic information required for the expression of CTL function can occur in the absence of detectable DNA synthesis.

scholarly journals GENERATION OF CYTOTOXIC T LYMPHOCYTES IN VITRO

1974 ◽  
Vol 140 (6) ◽  
pp. 1511-1521 ◽  
Author(s):  
H. Robson MacDonald ◽  
Jean-Charles Cerottini ◽  
K. Theodor Brunner
Keyword(s):  
T Lymphocytes ◽  
Physical Properties ◽  
Cell Lineage ◽  
Kinetic Studies ◽  
Large Cell ◽  
Velocity Sedimentation ◽  
Cell Fractionation ◽  
Anamnestic Response ◽  
Cell Fractions

Separation of cells by velocity sedimentation at unit gravity was utilized to investigate the physical properties of cytotoxic thymus-derived lymphocytes (CTL) generated in long-term mixed leukocyte cultures (MLC). In kinetic studies, CTL were found almost exclusively in the large cell fractions at the peak of the response on day 4, whereas the majority of CTL in day 14 MLC had the sedimentation properties of small lymphocytes. Reculture until day 14 of cells fractionated on the basis of size on day 4 indicated that the small CTL were derived exclusively from cells which had been large on day 4. Re-exposure of day 14 MLC cells to the original stimulating alloantigens resulted in significant cell proliferation and rapid regeneration of CTL activity. Cell fractionation experiments demonstrated that the cells in the day 14 MLC population which responded to the secondary allogeneic stimulus were small T lymphocytes, and that these cells rapidly developed into large, highly cytotoxic CTL following stimulation. Moreover, by restimulating on day 14 fractions which were selected on the basis of size on day 4, it was found that the responding small lymphocytes were themselves the progeny of cells which were large at the peak of the response. Since CTL and CTL progenitors showed concomitant changes in physical properties with time, the possibility exists that they belong to the same cell lineage, and hence that CTL can differentiate into cells which are no longer cytotoxic, but capable of mounting an anamnestic response.

scholarly journals Induction of specific immune unresponsiveness using purified mixed leukocyte culture-activated T lymphoblasts as autoimmunogen. I. Demonstration of general validity as to species and histocompatibility barriers.

1977 ◽  
Vol 146 (4) ◽  
pp. 1124-1137 ◽  
Author(s):  
L C Andersson ◽  
M Aguet ◽  
E Wight ◽  
R Andersson ◽  
H Binz ◽  
...  
Keyword(s):  
Side Effects ◽  
T Lymphocytes ◽  
Guinea Pig ◽  
Third Party ◽  
Velocity Sedimentation ◽  
General Validity ◽  
Negative Side Effects ◽  
T Lymphoblasts ◽  
General Tool

Normal immunocompetent T lymphocytes can be induced into specific proliferation if confronted with the relevant alloantigen in vitro. Such mixed leuko-cyteculture-activated T lymphoblasts carring idiotypic receptors on their surface can be purified using velocity sedimentation and serve as immunogen if administered in adjuvant to the autologous host. Autoblast immunization can be shown to lead to specific, long-lasting unresponsiveness against the relevant alloantigens, while leaving reactivity against third-party antigens intact. When tested as to general validity, it could be shown to function in all species analyzed (mouse, rat, and guinea pig) as well as across both major and minor histocompatibility barriers. No negative side effects have been noted so far. It would thus seem clear that autoblast immunization using the above described scheme may serve as a general tool in inducing long-lasting, specific unresponsiveness in any species and across any histocompatibility barrier.

Effects of Ca-Containing Phosphate Glasses on T Lymphocytes In Vitro

2005 ◽  
Vol 284-286 ◽  
pp. 597-602 ◽  
Author(s):  
A. Kesisoglou ◽  
Jonathan C. Knowles ◽  
I. Olsen
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Dna Synthesis ◽  
T Cell Activation ◽  
Cell Activation ◽  
Human Peripheral Blood ◽  
Suppressor Cells ◽  
Phosphate Glasses ◽  
Activated T Cells

Calcium phosphate-based glasses (PG) are of interest as both scaffold and delivery materials for tissue rebuilding because of their chemical similarity to bone. Since it is essential that these materials exhibit local and systemic biocompatibility and do not adversely affect host tissues, the present study was undertaken to examine the effects of PG containing different amounts of Ca on human T lymphocytes in vitro. This was carried out by measuring the effects of extracts of the PG on the direct and mitogen-induced activation of T cells from human peripheral blood, as well as assessing CD4 and CD8, surface antigens which define T-helper and T-suppressor cells, respectively. The results showed that DNA synthesis by resting T lymphocytes was unaffected by all the PG. However, extracts of the PG containing 24 mol% of Ca caused a very marked inhibition of mitogen-induced T cell activation. This PG also reduced both the resting CD4+ and CD8+ T cells, as well as activated CD8+ cells. In contrast, high Ca-PG significantly augmented DNA synthesis by mitogen-activated T cells. These experiments show that PG containing differing levels of Ca can have pronounced and differential effects on the activation and function of T lymphocytes in vitro.

scholarly journals Separation of helper and suppressor T lymphocytes. II. Ly phenotypes and lack of DNA synthesis requirement for the generation of concanavalin A helper and suppressor cells.

1977 ◽  
Vol 146 (3) ◽  
pp. 747-758 ◽  
Author(s):  
H Y Tse ◽  
R W Dutton
Keyword(s):  
T Lymphocytes ◽  
Dna Synthesis ◽  
Concanavalin A ◽  
Suppressor Cells ◽  
Blast Cell ◽  
Small Cells ◽  
Velocity Sedimentation ◽  
Con A ◽  
Helper Activity ◽  
Suppressor T Lymphocytes

Using a Ficoll velocity sedimentation gradient, we have been able to fractionate concanavalin A (Con A)-induced helper and suppressor cells into separate pools. Cells activated by Con A to mediate helper activity are Ly1+, do not require DNA synthesis for induction, and remain as small cells after activation. Suppressor cells are Ly23+, are found in the blast cell fraction and their induction is not inhibitable by prior treatment with mitomycin C or irradiation, both of which inhibit DNA synthesis. The implications of such findings are discussed.

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