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PubMedDate not supplied

Selective usage of TCR V beta in tumor-specific CTL lines isolated from ovarian tumor-associated lymphocytes.

We have developed a series of six CTL lines exhibiting preferential killing of autologous tumour cells from tumour-associated lymphocytes (TALs) infiltrating malignant ovarian ascites. Five out of six CTL lines showed increased percentages of V beta 8.1+ cells, four showed increased percentages of V beta 5.3+ cells and one showed increased percentages of V beta 6.7+ cells. On the contrary, fresh isolated TALs or autologous PBMCs, when stimulated by OKT3 mAb or other TAL cultures with nonspecific cytolytic function, did not show preferential usage of any of these families. Most important, V beta 8.1+ and V beta 6.7+ T cells within the CTL-TALs mediated cytoxicity against autologous targets. This represents the first demonstration of preferential usage of TCR V beta in ovarian tumor-specific CTLs and suggests possible association between tumor surveillance and TCR V beta genes.

Cell Line↗
PubMed1990

Tumour-induced immunity to H-Y-disparate skin grafts without concomitant priming of CTL.

A tumour, ET-5, arising as a subcutaneous mass in a C57BL/6 male mouse after treatment with a mutagen, has been found to elicit immunity to H-Y antigen in B6 female mice that have rejected the tumour. Anti-H-Y immunity is demonstrable in vivo by accelerated rejection of male skin grafts, and by the ability of spleen cells from ET-5-primed female mice to transfer immunity against H-Y antigen to immunodeficient hosts given indicator male skin grafts. However, spleen cells from ET-5-immune female mice fail to generate CTL specific for H-Y antigen when co-cultured with male stimulator cells in vitro. This finding implies that the generation of H-Y-specific immunity in vivo can occur in the absence of priming of CTL, and thus calls into question the necessity for CTL participation in H-Y-disparate tumour graft rejection.

Animals↗
PubMed1988

Identification by site-directed mutagenesis of amino acid residues contributing to serologic and CTL-defined epitope differences between HLA-A2.1 and HLA-A2.3.

Site-directed mutagenesis of HLA-A2.1 has been used to identify the amino acid substitutions in HLA-A2.3 that are responsible for the lack of recognition of the latter molecule by the HLA-A2/A28 specific antibody, CR11-351, and by HLA-A2.1 specific CTL. Three genes were constructed that encoded HLA-A2 derivatives containing one of the amino acids known to occur in HLA-A2.3: Thr for Ala149, Glu for Val152, and Trp for Leu156. Three additional genes were constructed that encoded the different possible combinations of two amino acid substitutions at these residues. Finally, a gene encoding all three substitutions and equivalent to HLA-A2.3 was constructed. These genes were transfected into the class I negative, human cell line Hmy2.C1R. Analysis of this panel of cells revealed that recognition by the antibody CR11-351 was completely lost when Thr was substituted for Ala149, whereas substitutions at amino acids 152 and 156, either singly or in combination, had no effect on the binding of this antibody. The epitopes recognized by the allogeneic and xenogeneic HLA-A2.1 specific CTL clones used in this study were all affected by either one or two amino acid substitutions. Of those epitopes sensitive to single amino acid changes, none were affected by the substitution of Thr for Ala149, whereas all of them were affected by at least one of the substitutions of Glu for Val 152 or Trp for Leu156. Overall, amino acid residue 152 exerted a stronger effect on the epitopes recognized by HLA-A2.1 specific CTL than did residue 156. Of those epitopes affected only by multiple amino acid substitutions, double substitutions at residues 149 and 152 or at 152 and 156 resulted in a loss of recognition, whereas a mutant with substitutions at residues 149 and 156 was recognized normally. This reemphasizes the importance of residue 152 and indicates that residue 149 can affect epitope formation in conjunction with another amino acid substitution. These results are discussed in the context of current models for the recognition of alloantigens and in light of the recently published three-dimensional structure of the HLA-A2.1 molecule.

Amino Acid Sequence↗
PubMed1985

Interleukin 2-mediated induction of lytic activity in a cloned murine CTL line.

We have analyzed the ability of interleukin 2 (IL 2) to induce lytic activity within a cloned murine H-2Dd-specific CTL line. Weakly lytic CTL harvested 6 to 7 days after previous stimulation with irradiated DBA/2J spleen cells and conditioned medium from secondary MLC (MLC SN) could be reactivated to high antigen-specific lytic activity with highly purified gibbon IL 2 or E. coli-produced human recombinant DNA IL 2. Dose-response curves with IL 2 and MLC SN suggest that IL 2 may be the principal detectable activity in MLC SN that is active on these CTL. Doses of IL 2 or MLC SN that were saturating for the induction of lytic activity were suboptimal for the expression of DNA synthesis measured by 3HTdR incorporation. This is consistent with a mechanism in which different threshold IL 2 concentrations are required to induce these two biologic responses. Finally, we show that IFN-gamma has little effect on the expression of lytic activity either alone or in combination with IL 2 in this bioassay.

Absorption↗
PubMed1985

Human cytotoxic T cell clones directed against herpes simplex virus-infected cells. III. Analysis of viral glycoproteins recognized by CTL clones by using recombinant herpes simplex viruses.

Human cytotoxic T cell (CTL) clones specific for herpes simplex virus (HSV) type 1- and type 2-infected cells were generated and were analyzed with regard to the viral glycoproteins they recognize on autologous HSV-infected cells. By use of target cells infected with wild-type HSV strains, a gC deletion mutant of HSV-1, and HSV-1 X HSV-2 intertypic recombinants, some HSV-1-specific CTL clones were found to be directed against L region-encoded gA/B-1, and others against S region-encoded glycoproteins (gD-1 or gE-1). Some HSV-2-specific clones were found to be directed against L region-encoded gC-2, whereas others were directed against S region-encoded glycoproteins (gD-2, gE-2, or gG). These findings provide direct evidence that several HSV glycoproteins that are expressed on the surface of HSV-infected cells serve as recognition structures for human HSV-specific CTL.

Clone Cells↗
PubMed1985

Generation of primary murine CTL specific for allogeneic and xenogeneic MHC determinants upon stimulation with murine L cells transfected with class I genes.

This communication describes in vitro culture conditions that permit the use of MHC gene-transfected L cells as stimulators of primary CTL responses. The use of L cells as stimulators usually results in the generation of "nonspecific" anti-L cell cytotoxicity too great to permit visualization of antigen-specific CTL responses. This study demonstrates that the generation of such anti-L cell cytotoxicity can be abrogated by strategies that prevent the in vitro activation of self-Ia-restricted TH cells. These maneuvers allowed the use of L cell transfectants as stimulators of allospecific and xenospecific CTL precursors in primary in vitro mixed lymphocyte reaction cultures.

Animals↗
PubMed1989

[The functional maturation of Langerhans cells in CTL induction during tissue culture].

In the previous report, we investigated the effects of tissue culture on the APC function of murine epidermal Langerhans cells (LC) in the induction of allo-CTL in vitro, and found that (1) cultured ear LC expressed increased amounts of Ia antigens on their cell surface, and (2) they induced extremely enhanced levels of CTL over those produced by freshly prepared ear LC and also (3) cultured tail LC were proved to be able to induce CTL for the first time. It seemed that tissue culture decreased the functional heterogeneity among the murine ear LC and tail LC in addition to that among Ia+ APC in spleen and in epidermis. In this study, we investigated the culture conditions that increase the APC function of LC. Our data indicate that LC cultured with dermal components exhibited more enhanced APC function than LC cultured in single cell suspension with only epidermal cells. Recent studies indicate that IL-1 and GM-CSF, which keratinocytes release, are essential for freshly prepared LC to mature into highly efficient APC that resemble splenic dendritic cells. We found dermal factors are more important than epidermal ones for LC to mature in tissue culture.

Animals↗
PubMed1989

[Induction of LAK cells and CTL in patients with brain tumor and research of its clinical application].

We studied whether lymphokine-activated killer (LAK) cells and cytotoxic T lymphocytes (CTL) were capable of being induced in vitro from peripheral blood lymphocytes of patients with brain tumor. The LAK cells were generated by culturing recombinant IL-2 with peripheral blood lymphocytes. The culture was continued for 72 hours; then cytotoxicity to Hela cell was examined by 4-hr 51Cr release assay. LAK cells were induced from lymphocytes of patients with brain tumor, but the cytotoxicity was rather less than that of healthy subjects, and it was accompanied by clinical deterioration. CTL was generated by co-culture of patient's peripheral blood lymphocytes and autologous brain tumor cells with addition of rIL-2. The cytotoxicity to autologous and allogenic brain tumor cells was examined by 16-hr51Cr release assay. The cytotoxicity to autologous tumor was approximately 30-40%, and there was cross reaction to allogenic tumor cells. The adoptive transfer of CTL to four patients was performed. One patient improved clinically, and on CT scan, growth of the tumor appeared to have been reduced.

Adolescent↗
PubMed1988

Defective generation of alloreactive cytotoxic T lymphocytes (CTL) in human monoclonal gammopathies.

The generation of cytotoxic T lymphocytes (CTL) towards allogeneic cells was investigated in 19 patients with monoclonal gammopathy of undetermined significance (MGUS) and 31 patients with multiple myeloma (MM). This function was significantly decreased in all patients. The cytotoxic deficiency was more pronounced in MM with poor prognosis than MM with good prognosis and MGUS patients. A phenotypic analysis of PBT lymphocytes showed that poor prognosis MM also had the highest proportions of activated cells (HLA-DR+) in CD8+ subpopulations. CTL were generated after depletion of CD11+ lymphocytes (including suppressor cells) or after inhibition of suppressor function with deoxyguanosine. No increase of cytotoxicity was detected under these conditions. Exogenous supplementation of recombinant interleukin 2 (rIL-2) was also ineffective. These data indicate that MG PBT lymphocytes are unable to fully differentiate into CTL following allogeneic stimulation. This deficiency is most evident in MM patients already showing the poorest prognosis and the most altered T cell phenotype.

Antigens, Surface↗
PubMed1987

The degree of CTL-induced DNA solubilization is not determined by the human vs mouse origin of the target cell.

CTL-mediated lysis is unique among lytic mechanisms in inducing rapid, prelytic nuclear disintegration. Target cell DNA can be solubilized within minutes as a result of degradation, which can proceed to the nucleosomal level, presumably mediated by endonucleases that are either endogenous or injected by the CTL. Nuclear disintegration has been reported for mouse lymphoid target cells by several groups. However, previous studies in which human target cells were studied saw little or no DNA solubilization. We here report rapid, extensive CTL-induced solubilization of DNA in human lymphoid target cells; on the other hand, we found that three mouse cell lines exhibit little or no nuclear disintegration. We conclude that the degree of nuclear disintegration depends on the nature of the target cell, but is not determined by the species of origin of the target cell.

Animals↗
PubMed1985

Activation of virus specific CTL clones: antigen-dependent regulation of interleukin 2 receptor expression.

Interleukin 2 (IL 2) is a lymphocyte-specific growth hormone, whose effect on lymphocyte proliferation is exerted through a cell surface receptor expressed on activated lymphocytes. In this report we have used monoclonal antibodies directed to the murine IL 2 receptor to examine the regulation of the IL 2 receptor expression on cloned populations of influenza virus-specific CTL. The CTL clones, which are dependent on both specific antigenic stimulation and exogenous IL 2 for continuous in vitro propagation, express high levels of the IL 2 receptor shortly after antigenic stimulation (day 2 or 3). Over the next 5 to 8 days of in vitro cultivation in IL 2-containing medium, these cloned CTL cells express decreasing levels of IL 2 receptor. Concomitant with this fall in IL 2 receptor expression, the cells become refractory to the IL 2 proliferative stimulus. The cloned cells remain refractory to IL 2 until specifically stimulated by antigen, which induces high levels of the IL 2 receptor on the cells and renders the cells sensitive to IL 2 once again. These results support the concept that IL 2 receptor expression on activated T lymphocytes is transitory and that receptor expression is endogenously regulated in the activated T lymphocytes. These results also suggest that antigen plays a primary role in regulating T lymphocyte proliferation by maintaining IL 2 receptor levels.

Animals↗
PubMed1980

Multiple CTL subsets generated by H-2.L locus products stimulation: evidence for an antigenic determinant private to H-2.Ld.

Analysis of the fine specificity of CTL subpopulations raised by an H-2.L locus products stimulation (H-2dm2 anti-H-2d) was performed by absorption experiments by using monolayers of macrophages of H-2m, H-2q, H-2b, and H-2k haplotypes. The results show the existence of four CTL subsets. The pattern of reactivity of three of them could be correlated with that of antibodies present in H-2dm2 anti-H-2d antisera (anti-H-2.64, anti-H-2.65, and anti-H-2.Kk). The fourth CTL subset reacted with a specificity unique to H-2.Ld molecules (a private specificity?), absent on cells from H-2m, H-2q, H-2b, and H-2k haplotypes, and undescribed as yet by serologic methods. These data support the hypothesis that the H-2.L locus products are comparable in their antigenic properties to those of the H-2.K and H-2.D loci.

Absorption↗
PubMed1984

LFA-1, LFA-2, and LFA-3 antigens are involved in CTL-target conjugation.

Three cell surface antigens associated with the CTL-target cell interaction were previously identified by generation of mAb against OKT4+, HLA-DR-specific CTL, and selection for inhibition of cytolysis in a 51Cr-release assay. In this report, we showed that these mAb inhibit cytolysis by blocking CTL-target cell conjugate formation. It appears that LFA-1, LFA-2, and LFA-3 are cell surface structures involved in strengthening effector-target adhesion that accompanies antigen-specific recognition.

Antibodies, Monoclonal↗
PubMed1984

Antigen-specific xenogeneic CTL activity in the Syrian hamster.

Previous studies of the Syrian hamster have demonstrated a lack of cytotoxic T lymphocyte (CTL) activity in vaccinia virus-infected animals. Our laboratory has reexamined CTL activity in both the classical inbred strains, MHA, CB, and LSH, as well as the recently inbred strain MIT. Primary and secondary CTL specific for the immunizing antigen have been detected after in vitro culture in MIT but were not demonstrable in the classical strains. Only lymph node cells of the responding animal demonstrated this activity, spleen cells being phenotypically devoid of such a response. Identification of the cell responsible for cytolysis as a T cell was demonstrated by nylon wool nonadherence, specificity on Con A blasts, and the lack of surface immunoglobulin, as demonstrated by cell-sorter analysis.

Animals↗
PubMed1984

Early loss of precursors of CTL and IL 2-producing cells in the development of neonatal tolerance to alloantigens.

Bulk culture and limiting dilution analysis (LDA) were used to follow the ontogeny of the tolerant state in CBA/ HT6T6 mice neonatally tolerized to allogeneic histocompatibility antigens. Advantage was taken of the fact that the lymph nodes (LN) of young mice show immunocompetence before spleen cells do, allowing analysis of actual reactivity as early as 1 wk of age. At 1 wk, the LN cells of mice tolerized i.v. showed a loss of CTL reactivity in bulk culture specific for the tolerizing antigens; a corresponding specific decrease was seen in the frequency of CTL precursors (CTLp). At the same age, however, proliferative responses and interleukin 2 (IL 2) production in MLC were nonspecifically depressed in the tolerized animals. LDA of IL 2 producer precursor frequency (IL- 2Tp ) showed that there was a nonspecific loss of 50% of functional alloreactive IL- 2Tp , accompanied by a larger specific decrease of 90% in the frequency of IL- 2Tp responding to the injected alloantigens. These characteristics of the tolerant state persisted through at least 4 wk of age. Neither the proliferative nor CTL response deficiencies could be overcome by the addition of Con A supernatant containing IL 2. Mixing experiments failed to show evidence of suppressor cell involvement in the loss of the proliferative response. Our results indicate that the specific loss of alloreactivity after tolerization is due to clonal inactivation or deletion of both CTLp and IL- 2Tp , which is obvious as early as 7 days of age. In addition, the differences in the specificity of the clonal inactivation between CTLp and IL- 2Tp suggest the existence of independent mechanisms for tolerization.

Animals↗
PubMed1982

Host immune response to reovirus: CTL recognize the major neutralization domain of the viral hemagglutinin.

Previous studies have demonstrated the importance of the hemagglutinin (HA) of reovirus in determining virus-specific immune responses. In this study, we have used anti-HA monoclonal antibodies and reoviruses with antigenically altered HA proteins to further analyze the CTL response against the HA. We showed that reovirus-specific CTL primarily recognize one distinct antigenic domain on the HA. These results emphasize the fine specificity of the T cell receptor that recognizes viral determinants. The CTL response is directed against the region of the HA that is also responsible for neurotropism and binding to neutralizing antibody.

Animals↗
PubMed1983

Comparative structural analysis of HLA-A2 antigens distinguishable by cytotoxic T lymphocytes. II. Variant DK1: evidence for a discrete CTL recognition region.

Multiple amino acid sequence differences distinguish individual HLA antigens. Those residues important in immune recognition events have not been defined. Recent studies have identified HLA-A2 structural variants that, although serologically indistinguishable from other HLA-A2 antigens, are recognized poorly, if at all, by HLA-A2-restricted, influenza virus-immune, or HLA-A2-specific alloimmune CTL. In this study we utilize double-label tryptic peptide comparisons performed by both reverse-phase HPLC and cation exchange chromatography, in conjunction with conventional and microsequence analysis, to characterize the HLA-A2 heavy chains derived from variant DK1. We detect a single tryptic peptide that distinguishes DK1 HLA-A2 from the predominant HLA-A2 heavy chain species. This peptide spans residues 147 to 157 in the second heavy chain domain, and carries substitutions at positions 149, 152, and 156. Residues in this segment of the polypeptide are also altered in another HLA-A2 variant, as well as one H-2Kb mutant. Thus, this segment appears to be critical in forming determinants important in CTL recognition of class I antigens in general. On the basis of these and other results, we suggest that in contrast to recognition by alloantibodies, a discrete region of class I antigens may be crucial for CTL recognition.

Amino Acid Sequence↗
PubMed1981

The amino acid sequence of residues 1-104 of CTL-1, a bovine H1 histone.

The amino acid sequence of the first 104 residues of calf thymus H1 histone subfraction (CTL-1), one of the H1 histones from bovine thymus, was determined by use of peptides derived from chymotryptic and staphylococcus protease digestion. The first 35 residues differ from the corresponding regions of a rabbit thymus H1 (RTL-3) and trout H1 by 30 and 39%, respectively, while in the region between residues 36 and 104 CTL-1 differs from the rabbit histone by only 4% and from the trout histone by only 16%. Although the differences between CTL-1 and sea urchin H1 are much greater, it is still evident that the sequence between residue 36 and residue 104 has been conserved much more than that between residues 1 and 35.

Amino Acid Sequence↗