Introduction The transcription factor HELIOS is primarily known for its expression in CD4 regulatory T cells, both in humans and mice. In mice, HELIOS is found in exhausted CD8 T cells. However, information on human HELIOS + CD8 T cells is limited and conflicting. Methods In this study, we characterized by flow cytometry and transcriptomic analyses human HELIOS + CD8 T cells. Results These T cells primarily consist of memory cells and constitute approximately 21% of blood CD8 T cells. In comparison with memory HELIOS - T-BET high CD8 T cells that displayed robust effector functions, the memory HELIOS + T-BET high CD8 T cells produce lower amounts of IFN-γ and TNF-α and have a lower cytotoxic potential. We wondered if these cells participate in the immune response against viral antigens, but did not find HELIOS + cells among CD8 T cells recognizing CMV peptides presented by HLA-A2 and HLA-B7. However, we found HELIOS + CD8 T cells that recognize a CMV peptide presented by MHC class Ib molecule HLA-E. Additionally, a portion of HELIOS + CD8 T cells is characterized by the expression of CD161, often used as a surface marker for identifying T C17 cells. These CD8 T cells express T H17 /T C17 -related genes encoding RORgt, RORa, PLZF, and CCL20. Discussion Our findings emphasize that HELIOS is expressed across various CD8 T cell populations, highlighting its significance beyond its role as a transcription factor for Treg or exhausted murine CD8 T cells. The significance of the connection between HELIOS and HLA-E restriction is yet to be understood.
Nine asymptomatic members of a family of Belgian origin, spanning three generations, present typical features of heterozygous beta-thalassemia. Since no mutation was detected with a large panel of oligonucleotide probes, the thalassemia gene was investigated by direct sequencing of DNA segments amplified by the polymerase chain reaction. A T->C transition was detected in the translation initiation codon (ATG). The mutation, which abolishes an Nco I restriction site, was further confirmed by enzymatic digestion as well as by dot-blot hybridization of the amplified products with allele-specific oligonucleotide probes. It produced a beta zero-thalassemia phenotype characterized by marked microcytosis and hypochromia, as well as by an in vitro beta/alpha chain synthesis ratio close to O.5. Search for haplotype linkage showed the mutation to be associated with haplotype IX + - + + + +.
East Coast fever, caused by the tick-borne intracellular apicomplexan parasite Theileria parva , is a highly fatal lymphoproliferative disease of cattle. The pathogenic schizont-induced lymphocyte transformation is a unique cancer-like condition that is reversible with parasite removal. Schizont-infected cell-directed CD8 + cytotoxic T lymphocytes (CTL) constitute the dominant protective bovine immune response after a single exposure to infection. However, the schizont antigens targeted by T. parva -specific CTL are undefined. Here we show the identification of five candidate vaccine antigens that are the targets of MHC class I-restricted CD8 + CTL from immune cattle. CD8 + T cell responses to these antigens were boosted in T. parva -immune cattle resolving a challenge infection and, when used to immunize naïve cattle, induced CTL responses that significantly correlated with survival from a lethal parasite challenge. These data provide a basis for developing a CTL-targeted anti-East Coast fever subunit vaccine. In addition, orthologs of these antigens may be vaccine targets for other apicomplexan parasites.
Abstract Human melanoma cell line MZ2‐MEL expresses several antigens recognized by autologous cytolytic T lymphocyte (CTL) clones. We reported previously the identification of a gene, named MAGE‐1, which codes for antigen MZ2‐E which is presented by HLA‐A1. Gene MAGE‐1 is expressed in many tumors of several types but not in normal tissues except for testis. We show here that gene MAGE‐1 directs the expression of another antigen recognized by CTL on the MZ2‐MEL cells. This antigen, which was named MZ2‐Bb, consists of MAGE‐1‐encoded peptide SAYGEPRKL bound to major histocompatibility molecule HLA‐Cw* 1601. The HLA‐Cw* 1601 allele was found to be expressed by 7 out of 99 individuals from a Caucasian population. Our results extend the range of tumor patients who could be eligible for immunization against MAGE antigens.
Human CD8 tumor infiltrating lymphocytes (TILs) with impaired effector functions and PD-1 expression are categorized as exhausted. However, exhaustion-like features reported in TILs might stem from their activation rather than the consequence of T-cell exhaustion itself. Using CRISPR-Cas9 and lentiviral overexpression in CD8 T-cells from healthy donors, we show that the TCR-induced transcription factor IRF4 promotes cell proliferation and PD-1 expression, and hampers effector functions and expression of NFκB-regulated genes. While CD8 TILs with impaired IFNγ production exhibited activation markers IRF4 and CD137, and exhaustion markers TOX and PD-1, activated T-cells in COVID-19 patients did not demonstrate elevated levels of TOX and PD-1. These results confirm that IRF4+ TILs are exhausted rather than solely activated. Our study indicates however that PD-1 expression, low IFNγ production, and active cycling in TILs are all influenced by IRF4 upregulation subsequent to T-cell activation.
Abstract The human tyrosinase gene has been reported previously to code for two distinct antigens recognized on HLA‐A2 melanoma cells by autologous cytolytic T lymphocytes (CTL). By stimulating lymphocytes of melanoma patient MZ2 with a subclone of the tumor cell line of this patient, we obtained a CTL clone that lysed this subclone but did not lyse other subclones of the same melanoma cell line. The sensitive melanoma subclone was found to express a much higher level of tyrosinase than the others, suggesting that the antigen recognized by the CTL might be encoded by tyrosinase. Transfection of a tyrosinase cDNA demonstrated that the CTL clone indeed recognized a tyrosinase product presented by HLA‐B*4403. The relevant antigenic peptide corresponds to residues 192–200 of the tyrosinase protein. Lymphoblastoid cells of the B*4402 subtype were not recognized by the CTL following incubation with the peptide. Nevertheless, by stimulating in vitro lymphocytes of a healthy HLA‐B*4402 donor with autologous adherent cells pulsed with the same peptide, we obtained a CTL clone which recognized tumor cells expressing tyrosinase and HLA‐B*4402. As HLA‐B44 is expressed in 24% of Caucasians, the tyrosinase‐B44 antigen may constitute a useful target for specific immunotherapy of melanoma.
Summary Bone marrow samples of 16 patients (two adults and 14 children) with a B lineage acute lymphoblastic leukaemia (ALL), and in whom Ig heavy chain gene rearrangements were detectable at diagnosis using polymerase chain reaction (PCR), were studied during evolution using PCR. The VDJ junctional fragment of the Ig heavy chain rearranged gene was amplified at diagnosis. After length reduction by restriction digestion, the amplified fragment was recovered by chromatography, labelled using a specific hexamer as a primer and directly used as a clonospecific probe. The sensitivity of the PCR ranged from 1:10 4 to 1:10 5 cells, depending on the patient's rearrangement. Residual disease (MRD) was detected in most of the patients achieving a complete remission after induction therapy, regardless of the long‐term outcome of treatment. However, in patients remaining in complete remission, the level of MRD showed a tendency to decrease and ultimately become undetectable for variable periods of time, while in patients eventually relapsing there was a trend for MRD to persist at stable levels and even to increase before relapse was clinically evident. We conclude that the use of a simplified methodology for obtaining a clonospecific probe from the Ig heavy chain gene, though less sensitive than the sequencing methodology, is a valuable and readily available tool to monitor MRD in a high proportion of B lineage ALL.
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