Search results for "major histocompatibility complex"

Consequences of antigen self-presentation by tumor-specific cytotoxic T cells.

2000

Abstract CDS-positive cytotoxic T cells (CTL) recognize antigenic peptides in combination with major histocompatibility complex (MHC) class I molecules on the surface of syngeneic antigen presenting cells (APC). In the present paper we show that cells from tumor antigen-specific CTL clones present their cognate antigenic peptide to other CTL from the same clone. Inter-CTL peptide presentation resulted in activation of the cells of one CTL clone to MHC-unrestricted lysis of bystander cells. In contrast to the behaviour of this clone, another CTL clone did not lyse bystander cells after incubation with the cognate peptide, but was activated to self-destruction. The human herpes virus Epstein-…

FOXP3 Inhibitory Peptide P60 Increases Efficacy of Cytokine-induced Killer Cells Against Renal and Pancreatic Cancer Cells

2019

Background/aim Cytokine-induced killer (CIK) cells are ex vivo expanded major histocompatibility complex (MHC)-unrestricted cytotoxic cells with promising effects against a variety of cancer types. Regulatory T-cells (T-reg) have been shown to reduce the effectiveness of CIK cells against tumor cells. Peptide P60 has been shown to inhibit the immunosuppressive functions of T-regs. This study aimed at examining the effect of p60 on CIK cells efficacy against renal and pancreatic cancer cells. Materials and methods The effect of P60 on CIK cytotoxicity was examined using flow cytometry, WST-8-based cell viability assay and interferon γ (IFNγ) ELISA. Results P60 treatment resulted in a signifi…

H-2-linked murine cytotoxic T cell responses specific for sendai virus-infected cells

1978

CBA (H-2k) mouse-derived lymphochoriomeningitis virus and herpes simplex virus-specific cytotoxic T lymphocytes lyse virus-infected target cells compatible on either the H-2k or H-2D region. In contrast, CBA, C3H and AKR (H-2k) mouse-derived sendai virus-specific cytotoxic T lymphocytes (CTL) fail to lyse H-2D-compatible virus-infected cells. A similar lack of H-2D region-associated lytic activity was found with C57BL/6 and C57BL/10 (H-2b) mice as well as with the recombinants B10.A (2R) [Kb-Db] and B10.A (4R) [Kk-Db]. On the other hand, BALB/c (H-2d) mice and A/J (H-2a) mice do generate H-2Dd-associated sendai virus-specific CTL. These results are in contrast to those obtained with (CBA X …

Upregulation of Major Histocompatibility Complex Class I on Liver Cells by Hepatitis C Virus Core Protein via p53 and TAP1 Impairs Natural Killer Cel…

2003

ABSTRACTThe mechanisms of immune evasion and the role of the early immune response in chronic infection caused by hepatitis C virus (HCV) are still unclear. Here, we present evidence for a cascade of molecular events that the virus initiates to subvert the innate immune attack. The HCV core protein induced p53-dependent gene expression of TAP1 (transporter associated with antigen processing 1) and consecutive major histocompatibility complex (MHC) class I upregulation. Moreover, in p53-deficient liver cell lines, only reconstitution with wild-type p53, but not mutated p53 lacking DNA binding capacity, showed this effect. As a consequence of increased MHC class I expression, a significantly …

Lymphokine activated killer cells.

1989

Various subpopulations of human leukocytes may be induced by lymphokines to exert cytotoxic activity. In man major histocompatibility complex non-restricted tumor cell lysis by interleukin-2 (IL-2) induced peripheral blood lymphocytes is attributed mainly to natural killer cells. These T cell receptor negative large granular lymphocytes are called lymphokine activated killer (LAK) cells. In order to explore the potential of LAK cells in tumor therapy, several clinical studies have been conducted, using IL-2 alone or in combination with ex vivo IL-2-activated peripheral blood lymphocytes. Objective responses have reproducibly been achieved only in renal cell carcinoma and malignant melanoma …

Amino acid substitutions at position 97 in HLA-A2 segregate cytolysis from cytokine release in MART-1/Melan-A peptide AAGIGILTV-specific cytotoxic T …

1996

CD8+ T lymphocytes recognize antigenic peptides presented by major histocompatibility complex (MHC) class I molecules. Individual peptide termini appear to be fixed at the C- and N-terminal ends. In contrast, central peptide side chains residues may point in different directions and exhibit limited flexibility, dependent on the MHC class I structural variation. For instance, position 97 in HLA-A201 has been shown to shift individual peptide species into different coordinations, one oriented towards the peptide N terminus, or more towards the C-terminal end. The conformational shape of such non-anchor peptide residues may affect the affinity of MHC/peptide/TCR interaction, resulting in quant…

Enhanced susceptibility to cytotoxic T lymphocytes without increase of MHC class I antigen expression after conditional overexpression of heat shock …

1999

Antigenic peptides have been found associated with heat shock proteins (HSP) including cytoplasmic HSP70 and heat shock cognate protein 70 as well as the endoplasmic reticulum-resident glucose-regulated protein 94. Recently, HSP70 transfection has been reported to increase MHC class I cell surface expression and antigen presentation on mouse melanoma B16 cells (Wells et al., Int. Immunol. 1998. 10: 609). To analyze the effect of HSP70 on MHC class I cell surface expression and lysability of target cells we transfected a human melanoma cell line with the rat Hsp70-1 gene using the Tet-On system for conditional overexpression of HSP70. Induction of HSP70 did not increase cell surface expressi…

Impact of thymus on the generation of immunocompetence and diversity of antigen-specific MHC-restricted cytotoxic T-lymphocyte precursors.

1981

Isolation of Mhc class I cDNAs from the axolotl Ambystoma mexicanum.

1997

Class I major histocompatibility complex (Mhc) cDNA clones were isolated from axolotl mRNA by polymerase chain reaction (PCR) and by screening a cDNA phage library. The nucleotide and predicted amino acid sequences show definite similarities to the Mhc class Ialpha molecules of higher vertebrates. Most of the amino acids in the peptide binding region that dock peptides at their N and C termini in mammals are conserved. Several amino acids considered to be important for the interaction of beta2-microglobulin with the Mhc alpha chain are also conserved in the axolotl sequence. The fact that axolotl class I A cDNAs are ubiquitously expressed and highly polymorphic in the alpha1 and alpha2 doma…

Structure of MHC class I and class II cDNAs and possible immunodeficiency linked to class II expression in the Mexican axolotl

1998

Despite the fact that the axolotl (Ambystoma spp. a urodele amphibian) displays a large T-cell repertoire and a reasonable B-cell repertoire, its humoral immune response is slow (60 days), non-anamnestic, with a unique IgM class. The cytotoxic immune response is slow as well (21 days) with poor mixed lymphocyte reaction stimulation. Therefore, this amphibian can be considered as immunodeficient. The reason for this subdued immune response could be an altered antigenic presentation by major histocompatibility complex (MHC) molecules. This article summarizes our work on axolotl MHC genes. Class I genes have been characterized and the cDNA sequences show a good conservation of non-polymorphic …