PubMed Health⌕ Search

Biomedical subjects

R B Levy

Publications and source records attributed to R B Levy.

At least 73 records · Page 4Linked to original sources
PubMed1982

Induction of cell-mediated cytotoxic self responses by epidermal cells modified with a haptenic sulphydryl reagent.

Murine epidermal cells (EC) act as stimulator cells in the generation of allogeneic cytotoxic T lymphocytes (CTL) in cell-mediated lympholysis (CML) and are suitable targets for allogeneic and hapten-self CTL. To analyse the role of EC in the generation of and recognition by anti-self CTL, syngeneic hapten-modified murine EC were used as in vivo and in vitro stimulating populations and as target cells in a hapten-self CML system. Epidermal cells were modified with the sulphydryl-reactive haptenic reagent N-iodoacetyl-N'-(5-sulphonic-1-naphthyl)ethylenediamine (I-AED). C3H.SW (H-2b) AED-self CTL responses were generated by stimulation with syngeneic AED-modified EC and were readily demonstrated when tested on syngeneic hapten-modified EC. These CML responses were hapten-specific and H-2 restricted. No substantial difference was detected in the ability of AED-modified EC and spleen cells (SC) to stimulate the generation of secondary AED-self CTL. Cold target inhibition experiments with hapten-modified EC and SC blockers did not reveal tissue-specific recognition of hapten-modified EC or SC targets by AED-self CTL. These findings demonstrate that hapten-modified EC, when used for priming in vivo and subsequently for in vitro sensitization, can induce hapten-specific self CTL that are reactive against syngeneic hapten-modified EC.

Animals↗
PubMed1982

H2Kk can influence whether cytotoxic T lymphocytes recognize trinitrophenyl in association with H2Dk unique or H-2Kk and H-2Dk shared self determinants.

The present study investigates the effect of trinitrophenyl- (TNP) modified H-2Kk (TNP-Kk) antigens on the generation of anti-TNP-Dk restricted cytotoxic T lymphocyte (CTL) responses. C3H.OH mice were primed to TNP-self by skin-painting with trinitrochlorobenzene, and spleen cells from these primed mice were subsequently stimulated in vitro with TNP-self. The effector cells generated exhibited appreciable lysis of TNP-modified C3H.OH blast target cells. Cold target inhibition studies demonstrated the generation of two effector cell populations: one that recognizes TNP in association with unique Dk self determinants, and one that recognizes TNP in association with self determinants shared between TNP-Kk and TNP-Dk. This was in contrast to primed C3H/He spleen cells, which did not generate CTL that recognized TNP in association with unique Dk self determinants. When spleen cells from (C3H/He x C3H.OH)F1 mice primed to TNP were stimulated in vitro with TNP-C3H.OH cells, unique Dk self determinants were recognized in association with TNP. However, in vitro stimulation of the same F1 responding cells with TNP-C3H/He or TNP-F1 cells failed to elicit CTL that utilized these Dk-unique self determinants. The findings of this study demonstrate that unique or shared H-2Dk determinants can be differentially utilized by CTL populations, depending on the H-2 alleles expressed by the stimulator cells.

Animals↗
PubMed1982

Cell-mediated lympholysis responses against autologous cells modified with haptenic sulfhydryl reagents. IV. Self-determinants recognized by wild-type anti-H-2Kb and H-2Db-restricted cytotoxic T cells specific for sulfhydryl and amino-reactive haptens are absent in certain H-2 mutant strains.

Virus-specific H-2-restricted cytotoxic T cells (CTL) have been found to discriminate between wild-type and mutant class I molecules. The only results reported concerning a hapten-self model, however, indicate that TNP-specific CTL do not discriminate between wild-type and mutant self determinants (7). In the present study, hapten-specific CTL generated against N-iodoacetyl-N'-(5-sulfonic-1-naphthyl) ethylene diamine-modified syngeneic cells (AED-self) were used to determine whether a hapten that is known to react with different cell surface sites than TNP can induce CTL that distinguish mutant H-2K and D molecules from those of wild type. The findings of this study indicate that H-2Kb-AED-self cytotoxic effector cells can discriminate between self-determinants of H-2Kb wild-type and the H-2bm1 and H-2bm11 mutants, but not between wild-type and the H-2bm6 and H-2bm9 mutants. H-2Db-AED-self effector cells were also found to discriminate between self-determinants of H-2Db wild-type and the H-2bm13 and H-2bm14 mutants. Furthermore, cold target competition experiments indicated that the bm1 and bm11 Kb products also lack some determinants recognized by anti-wild-type Kb TNP-specific CTL. These findings provide the first demonstration that hapten-self-specific effectors can detect alterations in H-2 mutant class I molecules. The results in the present report also support the hypothesis that haptens do not have to derivatize H-2 molecules in order to form antigens recognized by H-2-restricted CTL. These findings are discussed with respect to the involvement of self-determinants on MHC and non-MHC cell surface molecules.

Amines↗
PubMed1982

Preferential response patterns of cytotoxic T lymphocytes specific for fluorescein isothiocyanate-[FITC] modified autologous cells.

Murine cytotoxic responses to TNP-modified syngeneic cells (TNP-self) have been shown to exhibit preferential recognition of K or D end self products encoded by the H-2 complex. In the present study, a number of B10 congenic and recombinant mouse strains were investigated to determine the H-2K and H-2D-restricted FTC-self CTL response patterns, and these were compared with the CTL response patterns obtained for TNP-self. The results indicate that for strains possessing the H-2k,d,h2,h4 haplotypes, respectively, preferential CTL responses were observed against FTC recognized in association with Kk over Dk, Dd over Kd, and Kk over Db. These patterns of preferential CTL responses were the same as those reported for TNP-self as well as several anti-viral CTL responses. In contrast to the results obtained in the B10.A strain, in which Kk preference was observed over Dd for TNP-self CTL, no preferential CTL response was observed when FTC was recognized in association with Kk and with Dd. In this context, it was observed that the CTL response to FTC recognized in association with Dd was particularly strong. This strong D end-associated response was shown to involve D locus products, and no evidence was obtained indicating that L locus self products were involved. These studies are discussed with respect to the possibility that different haptens can be recognized by CTL in association with different self determinants encoded by the same H-2 gene products.

Animals↗
PubMed1981

Hapten specific TNP-reactive cytotoxic effector cells using epidermal cells as targets.

Epidermal spongiosis, invasion of mononuclear cells into the epidermis, and epidermal cell destruction are regular findings in allergic contact dermatitis. The mechanism(s) by which these changes occur is not known. We have examined the possibility that some of the pathological changes observed in allergic contact dermatitis could be accounted for by invasion of the epidermis by cytotoxic effector cells which recognize hapten-modified self-antigens and therein cause epidermal cell destruction. C3H and BALB/c mice were sensitized by epicutaneously applied 7% trinitrochlorobenzene (TNCB). 14 days later spleen cells from these mice were stimulated in vitro to trinitrophenylated- (TNP-conjugated) syngeneic spleen cells and their responses were compared to the in vitro responses of spleen cells from unsensitized mice. After 5 days of culture, effector cell activity was assayed on 51Cr-labeled TNP-conjugated syngeneic epidermal cells and on unconjugated epidermal cells. Cytotoxic activity was detected in the spleens of both mouse strains, but was greater in the C3H than the BALB/c strain. The cytotoxic effector cell activity was hapten specific in that spleen cells from TNCB sensitized mice did not cause lysis of fluorescein isothiocyanate (FITC) conjugated epidermal cells and spleen cells from FITC sensitized mice did not cause lysis of TNP-conjugated epidermal cells. No significant cytotoxic activity was detected on unconjugated epidermal cells. These findings suggest that destruction of the epidermis in allergic contact dermatitis may be contributed to by sensitized cytotoxic effector cells.

Animals↗
PubMed1981

Hemispheric specialization for tactile-spatial processing in preschool children.

Witelson (1976) found that boys but not girls showed right-hemisphere specialization for tactile-spatial processing as early as 6 yr. of age. In the present study, Witelson's task was administered to 46 normal 4- and 5-yr.-old girls and boys. Both sexes showed right-hemisphere specialization. There were no sex differences either in specialization or in over-all performance.

Child Development↗
PubMed1981

Detection of shared H-2Kk and H-2Dk antigens that function as self determinants for cell-mediated lympholysis to trinitrophenyl-self.

Spleen cells from C3H/He mice immunized in vivo to trinitrophenyl (TNP)-self were sensitized in vitro to TNP-self. These spleen cells displayed strong lysis on TNP-modified H-2D end-matched (Kd-Dk) targets as well as enhanced cytotoxicity against H-2 matched (Kk-Dk) or H-2K end-matched (Kk-Dd) target cells. Cold target-blocking studies showed that the lysis of TNP-Kd-Dk targets could be blocked by the addition of TNP-modified Kk-Dk, Kk-Dd Kk-Db, or Kd-Dk, but not by TNP-modified Kd-Dd, Kb-Db and Kq-Kq spleen cells. These results demonstrate that the lysis of TNP-Kd-Dk targets is not due to cross-reactive clones against TNP-Kd-Dd, Kb-Db or Kq-Dq antigens. Inhibition of the TNP-Kd-Dk target lysis by TNP-Kk-matched (Kk-Dd or Kk-Db) as well as TNP-Dk-matched (Kd-Dk) blockers also reveals that this target is lysed by clones directed against shared antigens between Kk-TNP and Dk-TNP, indicating that no cytotoxic response restricted for Dk-TNP only could be detected even after in vivo priming.

Animals↗
PubMed1981

Analysis of Ir gene control of cytotoxic response to hapten-modified self: helper T cells specific for a sulfhydryl hapten can substitute for an anti-TNP-H-2b self helper cell defect.

Helper T cells specific for N-iodoacetyl-N'-(5-sulfonic 1-naphthyl) ethylene diamine (I-AED) were generated in (C56BL/6 X C3H/He)F1 mice by immunization with I-AED-modified syngeneic cells (AED-self). The requirements for activation of hapten-induced helper cells were investigated. The results demonstrated that activation of AED and trinitrophenyl- (TNP) helper cells was strictly hapten specific. In addition, F1 AEd-helpers could be activated efficiently by either I-AED-modified H-2b or H-2k self components to enhance the anti-AED self-CTL responses. This contrasts with the previous findings demonstrating the failure of TNP-H-2b self to activate F1 TNP-helper cells. After AED-helpers were activated, they were capable of augmenting sensitization of cytotoxic T cells (CTL) against TNP-self. These results indicate that although the activation of hapten-reactive helper cells is antigen (hapten)-specific, the subsequent helper activity, as determined by augmentation of CTL responses against another hapten, is antigen nonspecific. Since helper function was antigen nonspecific, F1 AED-helper cells activated by AED-H-2b or AED-H-2k self were tested for their ability to augment the F1 and anti-TNP-H-2b CTL response. The results indicate that the Ir gene defect in the ability of F1 spleen cells to respond to TNP-H-2b self could not be corrected by these helper cells. These results are discussed in the light of Ir gene controlled differences in the activation of AED and TNP-helper cells and possible models for augmenting CTL responses against various antigens in strains that generate marginal helper activity to TNP-self.

Animals↗
PubMed1981

Cytotoxic T lymphocyte responses against alloantigens exhibit preferential effector cell activity for H-2K or H-2D region products similar to that for H-2 restricted responses.

The present study was designed to investigate the patterns of allogeneic cytotoxic T cell responses against H-2K and H-2D region products. B10.D2 anti-B10.A(2R) effector cells lysed K-end matched target cells approximately 5 times more efficiently than D-end matched target cells. In contrast, C57BL/10 anti-B10.A effector cells killed K-end or D-end matched target cells equally well, whereas C57BL/10 anti-B10.D2 CTL exhibited a slight preference for D-end matched target cells. These results demonstrate that whole H-2 disparate stimulating populations do not necessarily induce equivalent h-2K and H-2D region-specific CTL responses. The strength of the cytotoxic responses was found to correlate with the number of known serologically detectable specificities shared between the stimulating and target cell populations. The similarities between these allogeneic and MHC-restricted CTL response patterns (which are under Ir-like control) raise the possibility that this regulation reflects the number of K or D region self-antigens that can be recognized in association with a foreign antigenic determinant and suggests that allogeneic responses to major histocompatibility antigens are also self-restricted by MHC gene products. The possibility is considered that such Ir-like control is also a reflection of the amounts of H-2K and H-2D products shed from the cell surface.

Animals↗
PubMed1981

Cell-mediated lympholytic responses against autologous cells modified with haptenic sulfhydryl reagents. I. Effector cells can recognize two distinct classes of hapten-reactive self sites on cell surface proteins.

Mouse spleen cells were modified with a sulfhydryl-reactive reagent, N-iodoacetyl-N'-(5-sulfonic-1-naphthyl) ethylene diamine (I-AED) and used as stimulator cells in primary in vitro cultures with unmodified spleen cells of the same strain. CTL could be readily demonstrated when tested on hapten-modified syngeneic target cells. These CML responses were hapten specific and H-2 restricted. In the H-2b strain, effector cell populations were identified that recognized AED in association with K-end and D-end coded self MHC products. Functional modification of the target cells by I-AED can be effectively blocked by prereacting the cells with other SH-reagents, which is consistent with CTL recognition of the hapten on cysteine residues. Since these premodifications of the cell surface do not block the functional modification by trinitrobenzene sulfonate (TNBS), the sulfhydryl-reactive compounds and TNBS modify distinct classes of cell surface groups as determined by CTL function. The results of antibody inhibition experiments are also consistent with this interpretation. Using fluorescent labeled anti-hapten antibodies, FACS II analysis showed that there are approximately 20-fold fewer AED than TNP groups on the approximately 20-fold fewer AED than TNP groups on the cell surface when equivalent concentrations of I-AED and TNBS are compared. The possibility is discussed that these sulfhydryl-reactive compounds can be used together with the H-2Kb mutants for the localization of H-2 coded self determinants recognized in association with foreign antigens.

Animals↗
PubMed1981

Cell-mediated lympholysis responses against autologous cells modified with haptenic sulfhydryl reagents. II. Analysis of the genetic control and H-2-restricted pattern of cytotoxic responses to sulfhydryl and amino reactive reagents.

N-iodoacetyl-N'-(5-sulfonic-1-naphthyl)ethylene-diamine modified autologous cells are shown to induce respective high and low AED-self CTL responses by spleen cells from H-2b and H-2k mice. The lysis mediated by effector populations from both haplotypes was highly H-2 restricted. Cytotoxic responses induced by a 2nd sulfhydryl- (SH) specific reagent, dithionitrobenzoic acid (DTNB), were shown not to be cross-reactive at the effector cell level with AED-self but exhibited the same high and low CTL response patterns as those induced against AED-self. These Ir-effects reported for the 2 SH reactive compounds are discussed in relation to the opposite Ir-patterns demonstrated against a number of amino (NH2) reactive compounds. The difference of self-recognition sites is suggested to account for the contrasting results observed in the response patterns induced by SH- and NH2-reactive compounds. The AED-self CTL response was found to exhibit Kk-self over Db-self Ir regulation. Thus, this latter type of genetic control appears to function independently of whether the hapten is an SH- or NH2-reactive compound.

Animals↗
PubMed1980

Role of self and foreign antigenic determinants in allogeneic and self-restricted cytotoxic T cell recognition.

Murine spleen cells were sensitized in vitro to H-2 disparate allogeneic spleen cells and assayed on syngeneic target cells conjugated with the trinitrophenyl (TNP)-self or the fluorescein isothiocyanate (FITC)-self haptens, or on syngeneic target cells expressing the male H-Y antigen (H-Y self). The results indicated that allo-induced cytotoxic T lymphocytes (CTL) contained effectors that lysed both hapten-self but not H-Y self targets. Furthermore, it was demonstrated that separate populations of those allogeneic CTL were responsible for the lysis of TNP-self and FITC-self targets. This study also showed that cytotoxic effectors generated against the H-Y antigen with lytic activity equal to or greater than that of an allogeneically induced CTL response were unable to lyse hapten-self targets. These findings provide the first evidence that H-2 alloantigens may be unique in their ability to induce effectors that lyse hapten-conjugated autologous targets. These observations are discussed with respect to the self and foreign antigenic determinants involved in allogeneic and self-restricted CTL models.

Animals↗
PubMed1980

Regulation of T-cell-mediated lympholysis by the murine major histocompatibility complex. II. Control of cytotoxic responses to trinitrophenyl-K and -D self products by H-2K- and H-2D-Region genes.

An H-2K/IA recombinant mouse strain was used to map the genes within the H-2 complex which determine the ability to respond in cell-mediated lympholysis (CML) to low doses of trinitrophenyl-self (TNP-self). It was found that gene(s) which map to the K region are involved in regulation of CML response to low-dose TNP-self. It was also found that CML response to TNP recognized in association with H-2Dq was not detectable in this recombinant. These findings are discussed with respect to the involvement of the H-2K and H-2D regions by structural and/or regulator gene functions.

Animals↗
PubMed1980

Helper cell analysis in cytotoxic T lymphocyte responses. I. Activation of specific and cross-reactive helper effects in two hapten-modified self responses.

C3H/HeN mice were immunized by skin painting with trinitrochlorobenzene or by inoculation of fluorescein isothiocyanate (FITC)-conjugated syngeneic cells. Approximately four weeks later, spleen cells were removed, irradiated, and cocultured with spleen cells from normal mice. These cultures were stimulated with syngeneic cells conjugated with different concentrations of trinitrobenzene sulfonate (TNP-self) or FITC (FITC-self). The results demonstrate (a) appreciable helper cell activity from TNP-self and FITC-self-primed mice, as determined by enhanced hapten-specific cytotoxic T lymphocyte (CTL) responses, (b) that FITC helper activity enhanced the FITC-self CTL more efficiently than the TNP-self CTL response, and vice versa, (c) an alloantigenic stimulating population failed to activate TNP-self helper activity and (d) that the helper activity was not exclusively specific, since FITC helpers did enhance the anti TNP CTL response, and TNP helpers could enhance the anti-FITC-self CTL response. The results of this study indicate that these cell-mediated lympholysis models permit an analysis of hapten specificity and cross-reactivity at the different levels of cellular interaction involved in the generation of an H-2-restricted CTL response.

Animals↗