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A M Schmitt-Verhulst

Publications and source records attributed to A M Schmitt-Verhulst.

At least 19 recordsLinked to original sources
PubMed1992

Threshold tolerance in H-2Kb-specific TCR transgenic mice expressing mutant H-2Kb: conversion of helper-independent to helper-dependent CTL.

To evaluate the role of the structure of the class I molecule and associated peptide(s) in intrathymic selection and tolerance, mice expressing as a transgene (tg) a TCR specific for the H-2Kb alloantigen were crossed with mice expressing the mutant class I molecule H-2Kbm1 or H-2Kbm8. In H-2k/k TCR tg mice (in a situation of exclusive positive selection), peripheral tg TCR expressing (Ti+) CD8+ T cells showed high, suboptimal, and an absence of reactivity for H-2Kb, H-2Kbm1, and H-2Kbm8, respectively. In the peripheral lymphoid organs of TCR tg H-2k/k, H-2k/bm8, H-2k/bm1, and H-2k/b mice respectively, the tg TCR was expressed on T cells with decreasing intensity of surface CD8. Thymic subpopulations of TCR tg mice presented a pattern of negative selection with decreasing intensity from H-2k/b to H-2k/bm1 and H-2k/bm8. This suggests that a weak interaction between the TCR and H-2Kbm8 exists which partially results in negative, but not in positive, intrathymic selection. Results further indicate that expression of H-2Kbm8 does not induce tolerance to H-2Kb. In H-2k/bm1 mice, the peripheral Ti+ CD8lo cells express two distinct types of 'threshold' tolerance in vitro: (i) they generate cytotoxic T lymphocytes (CTL), in the presence of exogenous IL-2, which fail to respond to H-2Kbm1 but remain reactive to H-2Kb; and (ii) they do not make significant titers of IL-2 and do not significantly proliferate in response to H-2Kb, unlike the Ti+ CD8+ T cells from H-2k/k TCR tg mice which respond efficiently. These results show that tolerance is induced up to a level of non-reactivity within a given MHC environment: for the same TCR, CTL reactivity to H-2Kbm1 is totally lost, whereas CTL reactivity to H-2Kb is only slightly reduced. Additionally, proliferation and IL-2 production by Ti+ CD8+ cells in response to H-2Kb were strongly affected in H-2k/bm1 mice. Thus, in H-2k/k mice the Ti+ CD8+ cells behave as helper-independent, whereas in H-2k/bm1 mice CD8+ cells expressing the same TCR behave as helper-dependent CTL.

Animals↗
PubMed1979

H-2-linked genetic control of murine T-cell-mediated lympholysis to autologous cells modified with low concentrations of trinitrobenzene sulfonate.

Spleen cells from B10.BR and C57BL/10 (B10) mice were compared for their ability to generate primary in vitro cytotoxic responses to syngeneic cells modified with different concentrations (from 10 to 0.031 mM) of trinitrobenzene sulfonate (TNBS) (TNP-self). Although both strains generated effector cells to TNP-self in the range of 10-0.25 mM TNBS modification, effector activity of B10 cells was weaker than that of B10.BR cells. B10 spleen cells did not respond to syngeneic stimulating cells modified at 0.1 mM or lower, whereas B10.BR cells generated effector activity even when stimulated by TNP-self modified with as low as 0.031 mM TNBS. Fluorescence analysis of the modified cells using the FACS II indicated that equivalent quantities of TNP were conjugated to the surfaces of B10.BR and B10 spleen cells for any given concentration of TNBS modification. Similar strain-dependent differences were observed when the TNP was diluted out in the cultures by reducing the number of stimulating cells modified with 10 mM TNBS. These response patterns were verified by stimulating cultures of B10.BR and B10 spleen cells either with TNP conjugated to bovine serum albumin or bovine gamma globulin (B10.BR but not B10 cells responded to TNP-conjugated proteins) or with TNBS-modified glass-adherent spleen cells. The strain-dependent differences could also be detected at the effector phase, because optimally stimulated B10.BR, but not B10 effector cells, could lyse 0.1 mM TNBS-modified syngeneic target cells. The genetic parameters associated with the response and nonresponse patterns of B10.BR and B10 mice were further investigated by comparing the cytotoxic responses to low doses of TNP-self of spleen cells from the following strains: (a) C3H/HeJ (H-2k) and C3H.SW (H-2b); (b) BALB.K (H-2k) and BALb.b (h-2b); and (c) B10.A (H-2a) and B10.D2 (H-2d). The H-2k and H-2a, but not the H-2b and H-2d, strains generated cytotoxic responses to TNP-self when the syngeneic stimulators were modified with 0.1 mM TNBS. Further studies using (B10 X B10.BR)F1 responding cells and parental or F1-modified stimulating cells, indicated that the F1 cells generated cytotoxic activity to low doses of TNP in association with H-2k but not in association with H-2b self products. The results of this study indicate that H-2-linked genetic factors, expressed in the target as well as in the responding and/or stimulating cell populations, control the ability of inbred mouse strains to generate cytotoxic effector cells to low doses of TNP-self. Such dose-dependent genetic effects may be important in the regulation of immune responses activated in vivo by chronic exposure to infectious agents.

Animals↗
PubMed1979

Cell types required for H-2-restricted cytotoxic responses generated by trinitrobenzene sulfonate-modified syngeneic cells or trinitrophenyl-conjugated proteins.

Murine spleen cells were fractionated over nylon wool or Sephadex G-10 columns, and the cell types involved in the generation of trinitrophenyl (TNP)-specific, H-2 restricted (TNP-self) cytotoxic effector cells were studied from cultures stimulated with trinitrobenzene sulfonate (TNBS)-modified syngeneic cells, TNP-conjugated soluble proteins such as bovine gamma-globulin (TNP-BGG), or bovine serum albumin (TNP-BSA). Unfractionated or nylon nonadherent responding cells generated such effectors, irrespective of whether the cultures were stimulated with TNBS-modified cells or TNP-conjugated proteins. TNP-modified T lymphocytes, B lymphocytes, and phagocyte-enriched spleen cells were all capable of stimulating TNP-self effectors. TNP-self effectors. TNP-self as well as allogeneic cytotoxic responses were dependent on the presence of a radioresistant non-T cell that was removed by Sephadex G-10 fractionation and was replaced by irradiated, Thy 1.2-negative, glass adherent spleen cells, enriched in phagocytic cells. Results obtained by using glass adherent cells that were allogeneic or semi-syngeneic to the responding cells indicated that H-2 homology was not required for efficient glass adherent cell function, and that the H-2 restriction of TNP-self effectors is not determined by these glass adherent cells.

Animals↗
PubMed1978

H-2-restricted cytotoxic effectors generated in vitro by the addition of trinitrophenyl-conjugated soluble proteins.

Murine spleen cells from normal donors were cultured in vitro with trinitrobenzene sulfonate (TNBS)-conjugated soluble proteins, i.e., bovine gamma globulin (TNP-BGG) or bovine serum albumin (TNP-BSA). Addition of 100 mug of any of these TNP-proteins to the spleen cell cultures led to the generation of cytotoxic T-cell effectors which were H-2-restricted and TNP- specific. The lytic potential of such effectors was comparable to that generated by sensitization with TNBS-modified syngeneic cells, and was restricted to haplotypes shared at the K or K plus I-A, or the D regions of the H-2 complex. Greater effecter cell activity was generated by addition of TNP-BGG against TNBS-modified targets which shared K plus I-A than against modified targets which shared the D region with the responding cells, which suggests that the same immune response genes are involved when the response is generated by the addition of TNP-conjugated soluble proteins or of TNBS- modified cells. H-2-restricted, TNP-specific effecter cells were generated by culturing mouse spleen cells with syngeneic cells which had been preincubated with TNP- BGG or TNP-BSA for 1.5 h. The addition of unconjugated soluble proteins to the cultures did not result in cytotoxic effectors detectable on H-2-matched targets, whether the targets were prepared by modification with TNBS, or by incubation with either the unconjugated or TNP-conjugated proteins. Depletion of phagocytic cells in the tumor preparation by Sephadex G-10 column fractionation before incubation with TNP-BSA had no effect on their lysis by the relevant effector cells. Immunofluorescent staining of tumor target cells with anti-TNP antibodies indicated that TNP could be detected on the tumor cells within 10 rain of incubation with TNP-BSA. The cytotoxic response generated by addition of the TNP-proteins to spleen cell cultures was found to be T-cell dependent at the effector phase, as shown by the sensitivity of the lytic phase to absorbed RAMB and complement. Furthermore, the response did not appear to be attributable to antibody-dependent cellular cytotoxicity. Three mechanisms were considered which could account for the generation of H-2-restricted, TNP-specific, cytotoxic T-cell effectors by the addition of soluble TNP-proteins. These include covalent linkage of activated TNP groups from the soluble proteins to cell surface components, macrophage processing of the soluble conjugates and presentation to the responding lymphocytes in association with H-2-coded self structures, or hydrophobic interaction of the TNP-proteins to cell surfaces. Results obtained from sodium dodecyl sulfate gel patterns indicating that cell-bound TNP was still linked to BSA, and the observation that phagocytic-depleted cells could interact with the soluble TNP-proteins and function as H-2-restricted targets, appear not to favor the first two proposed mechanisms.

Animals↗
PubMed1977

H-2 homology requirements for secondary cell-mediated lympholysis and miced lymphocyte reactions to TNP-modified syngeneic lymphocytes.

Secondary cell-mediated lympholysis (CML) and mixed lymphocyte reactions (MLR) were generated in a tissue culture system against trinitrophenyl (TNP)-modified murine syngeneic spleen cells. H-2 homology between primary and secondary TNP-modified stimulating cells was required in order to restimulate in the secondary CML. Strong proliferative responses (MLR) were detected only in the secondary cultures, for which H-2 homology was also required between TNP-modified primary and secondary immunogens. Intra-H-2 mapping for the secondary MLR indicated that the relevant regions of homology were I, D, and K and/or I-A. Homology throughout the entire major histocompatibility complex or at K plus I-A gave stronger MLR than did cultures in which there was homology between the primary and secondary phases at I or D only.

Animals↗
PubMed1976

Multiple H-2 linked immune response gene control of H-2 D-associated T-cell-mediated lympholysis to trinitrophenyl-modified autologous cells: Ir-like genes mapping to the left of I-A and within the I region.

One of the more recent associations of the murine H-2 major histocompatibility complex (MHC) with immune function has been the finding that cytotoxic T-effector cells generated by sensitization with viral-infected (1-6), chemically modified (7-9), or weak transplantation antigen-associated (10,11) syngeneic cells can efficiently lyse target cells which express the same viral, chemical, or weak antigenic agent, and which share the H-2K and/or H-2D regions of the MHC with the responding and/or stimulating cells. Furthermore, an additional contribution of a gene(s) within the H-2 complex has been demonstrated which controls immune response potential (Ir genes) in the generation of cytotoxic effector cells to trinitrophenyl (TNP)-modified self components (12,13). In such studies it was found that certain B10 congenic strains generated good cytotoxic responses to both TNP- modified H-2K and H-2D region products, whereas other B10 congenic strains exhibited preferential or exclusive reactivity against TNP-modified H-2K region products. Some of these recombinant strains differing in response potential to TNP- modified H-2D products expressed the same haplotype at the D end, but differed at the K end of H-2. The low responsiveness observed in the B10.A strain to TNP-modified H-2D(d) when compared to B10.D2 and (B10.A x B10.D2)F(1) for the same specificity, suggested a role of dominant Ir genes which map in K, I-A, I-B, I-J, and/or I-E (12, 14). In the present report an attemnpt was made to further map within the MHC the Ir gene(s) controlling cell-mediated lympholysis (CML) to TNP-modified H-2D(d), by using recombinant mouse strains on the A and B10 backgrounds. Irrespective of the genetic background, the s and k haplotypes at the K end generated high and low cytotoxic responses, respectively, to H-2D(d)-TNP. The intermediate responder and low responder status of the A.TL and A.AL strains, respectively, indicated that a gene mapping in the K region of H-2 influences response potential. Furthermore, the differences in the levels of cytotoxicity detected in the A.TH and A.TL strains suggested an additional I region influence. Taken together these findings raise the possibility that multiple genes mapping within different regions of the MHC control the level of T-cell-mediated cytotoxicity to chemically modified autologous cells.

Animals↗
PubMed1976

Cell-mediated lympholysis of trinitrophenyl-modified autologous lymphocytes. Confirmation of genetic control of response to trinitrophenyl-modified H-2 antigens by the use of anti-H-2 and anti-Ia antibodies.

Splenic lymphocytes from B10.A and B10.D2 mice were sensitized in vitro to trinitrophenyl (TNP)-modified autologous spleen cells. The effector cells generated were assayed in a 51Cr-release assay on TNP-modified syngeneic or congenic spleen target cells. Effector cells from B10.A donors lysed TNP-modified H-2Kk- but not H-2Dd-region products, whereas B10.D2 effectors reacted with modified products of both the H-2Kd and H-2Dd regions. As an independent confirmation that this selective K-end lysis by B10.A effector cells is due to an H-2-linked responder cell defect (4), anti-H-2Kk but not anti-H-2Dd sera were shown to inhibit the lysis of B10.A-TNP targets by B10.A effectors. In contrast, anti-H-2Dd sera inhibited the lysis of B10.A-TNP targets by B10.D2 effectors. Anti-Ia antibodies had no detectable effect on lysis. Anti-TNP-keyhole limpet hemocyanin sera blocked the lysis of TNP-modified targets, irrespective of whether the effector cells were directed against TNP-modified autologous H-2 products or H-2 alloantigens. These results independently verify that B10. A responding lymphocytes do not generate effector cells to TNP-modified H-2Dd products, whereas B10.D2 lymphocytes do (4), and suggest that some TNP groups are sterically close to (or part of) the serologically defined H-2K- and H-2D-region antigens.

Animals↗
PubMed1976

Analysis of the role of different cell types in the genetic regulation of antibody production to the thymus-independent synthetic polypeptide poly (DTyr, DGlu)-poly (DPro)--poly (DLys).

The immune response potential of mice to the thymus-independent synthetic polypeptide poly (DTyr, DGlu)-poly(DPro)--poly(DLys)[D(T,G)-Pro--L] is genetically regulated. The defect in the ability of low responder mice to mount an immune response to this antigen appears to be expressed in their B cell population since the presence of thymocytes, or addition of "educated T cells" or supernatant of T cells after stimulation with the antigen neither enhanced, nor suppressed the level of antibodies produced in both low and high responder mice. Low responsiveness could not be enhanced either by stimulation of macrophages or by injection of poly(A) - poly(U) in contrast to the significant effect of these agents on low responses to the thymus-dependent poly(LTyr, LGlu)-poly(LPro)--poly(LLys) [L(T,G)-Pro--L]. These results suggest that macrophages do not participate in the limiting step, or are not involved at all, in antibody production towards the thymus-independent polypeptide. The antibodies produced in response to D(T,G)-Pro--L were found to be mainly of the 7 S class. T cells are not required for the production of mercaptoethanol resistant antibodies to this immunogen since they were found in intact mice as well as in T cell depleted animals.

Animals↗
PubMed1976

Mixed lymphocyte reactivity and cell-mediated lympholysis to D-end differences of the murine major histocompatibility complex. Comparison of in vitro responses to exclusive D-end or more extensive MHC differences.

In vitro mixed lymphocyte culture (MLC) responses and the in vitro induction of cell-mediated lympholysis (CML) were studied in congenic strain combinations in which the responding and stimulating strains differed either at the entire major histocompatibility complex (MHC) or only at the D end of the MHC. In contrast to previously reported studies, the relative strengths of stimulation by 'D end only' differences or by whole MHC differences were examined by stimulating identical responding populations with titrated numbers of stimulating cells that differed from the responder either at the D end only or over the entire MHC. When tested in this manner isolated D-end differences were sufficient to generate significant MLC and CML responses in each combination tested. Several 'D end only' differences (the responses of B10.A to B10.A(2R); of B10.A(2R) to B10.A; of B10.D2 to B10.HTG; and of B10.HTG to B10.D2 were several fold less efficient in stimulating MLC and CML responses than were control stimulating cells differing over the whole MHC. In contrast, when the mutant D-end allele da was present on the stimulating cell (the responses of B10.D2 to B10.D2(M504) and of B10 to B10.D2(R106)), stimulation by an isolated D-end difference was comparable to stimulation by broader MHC differences. These findings are discussed in terms of the possible functional complexity of the D region.

Animals↗
PubMed1975

Bifunctional major histocompatibility-linked genetic regulation of cell-mediated lympholysis to trinitrophenyl-modified autologous lymphocytes.

Murine thymus-derived lymphocytes can be sensitized in vitro to trinitrophenyl (TNP)-modified autologous spleen cells (1, 2). Cytotoxic effector cells were generated which were specific for TNP-modified target cells expressing the same H-2K and H-2D serological regions as the modified stimulator cells (3, 7). Spleen cells from two C57BL/10 congenic strains of mice sharing common I-C, S, and D regions, but differing at K, I-A, and I-B regions, generated different levels of lytic responses to the shared modified H-2Dd products upon sensitization with auto logous TNP-modified cells. Lymphocytes from an F1 between responder and nonresponder strain generated a level of cytolysis toward the H-2Dd modified specificity which was of the same order of magnitude as that obtained with the high responder, irrespective of whether F 1 or either parental strain of modified stimulator cell was used. These results suggest that the modification of H-2Dd products resulted in formation of new antigenic determinants in both parental strains. However, the difference observed in responsiveness appeared to be due to a gene or genes mapping in the K, I-A, or I-B region which influenced the ability of the responding lymphocytes to react to these modified H-2Dd products. Responsiveness was expressed as a dominant trait in the F1.

Alleles↗
PubMed1975

Mixed lymphocyte reactivity and cell-mediated lympholysis to trinitrophenyl-modified autologous lymphocytes in C57BL/10 congenic and B10-A recombinant mouse strains.

Cell-mediated lympholysis (CML) to trinitrophenyl (TNP)-modified autologous splenic lymphocytes has been recently reported in the mouse (1). Both the sensitization and effector phases of this phenomenon were shown to be T-cell mediated. Effector cell specificity studies indicated that modification of the target cells is a necessary but insufficient requirement for cytolysis, and suggested that altered cell surface components controlled by genes mapping in the mouse major histocompatibility H-2 complex (MHC) are important in the specificity of the cytotoxic reaction (1). In allogeneic models the generation of cytotoxic effector cells has been shown to be preceded or accompanied by immunogen- induced proliferation of responding lymphocytes, i.e. a mixed lymphocyte reaction (MLR) (2-5), although the generation of effectors may not necessarily always be the consequence of extensive cell proliferation (5). If the induction of cytotoxic effector lymphocytes by modified syngeneic spleen cells is characteristic of sensitization with cellular alloantigens, one would expect to find that sensitization with TNP-modified autologous cells would also induce thymidine incorporation by the responding cells in the culture. The present report demonstrates that both stimulation of thymidine incorporation and generation of cytotoxic effector cells are part of the in vitro response to TNP-modified autologous lymphocytes. However, the MLR to TNP- modified autologous cells consistently appeared to be less pronounced when compared with an allogeneic MLR, whereas the cytotoxic activity of the effector cells generated by sensitization against TNP-modified autologous cells was frequently as high as that detected against H-2 alloantigens. These two components of reactivity to "modified self" are verified in several C57BL/10 congenic and B10.A recombinant mouse strains.

Animals↗
PubMed1975

The effect of the thymus-independent antigens, collagen and synthetic collagen-like polypeptide, on the requirement of cell cooperation in the immune response to thymus-dependent antigens.

The effect of thymus-independent antigens on the need for cell cooperation in the immune response to thymus-dependent antigens was investigated. Irradiated recipient mice transplanted with either bone marrow cells or a mixture of bone marrow and thymus cells, were immunized with the thymus-independent antigen (Pro-Gly-Pro)n covalently conjugated to the thymus-dependent ovalbumin, or with a mixture of (Pro-Gly-Pro)n and ovalbumin. In both cases an effective response towards ovalbumin was observed in the absence of thymus cells as was found for the thymus-independent (Pro-Gly-Pro)n. The same effect on ovalbumin was demonstrated when a mixture of the thymus-independent collagen and ovalbumin was used for immunization. On the other hand, when irradiated reconstituted mice were immunized with a mixture of ovalbumin and the thymus-dependent gelatin, which is the denatured product of collagen, cell-to-cell cooperation was required for an immune response to both immunogens. The effect of (Pro-Gly-Pro)n and collagen on the response to the thymus-dependent ovalbumin in vivo was observed in in vitro experiments using sheep red blood cells (SRBC) as the immunogen as well. In the presence of reduced and carboxymethylated (RCM) Ascaris collagen and (Pro-Gly-Pro)n, nude spleen cells could produce significant numbers of plaque-forming cells towards SRBC. Thus, (Pro-Gly-Pro)n and collagen can deliver the signal required to stimulate B cells to produce antibody towards thymus-dependent antigens in the absence of T cells. In contrast to the results with (Pro-Gly-Pro)n and collagen, the thymus-independent synthetic polypeptide poly(DTyr, DGlu-)-poly(DPro)--poly(DLys) did not affect the requirement for cell cooperation of the thymus-dependent immunogens, ovalbumin and SRCB. It thus appears that the ability to substitute for T cells for antibody production towards thymus-dependent immunogens is not a general characteristic of thymus-independent antigens.

Animals↗