Human CD8⁺ CTL Recognition and In vitro Lysis of Herpes Simplex Virus‐Infected Cells by a Non‐MHC Restricted Mechanism

Abstract

Cytotoxic T lymphocytes (CTL) are important for the recognition and lysis of virally infected cells, but their effectiveness can be limited by viral immune evasion mechanisms. We investigated the immunophenotype and function of human CD8 T cells raised in response to herpes simplex virus (HSV). The expanded population contained cells of an activated and mature phenotype, as determined by the expressions of CD25, CD45RO, CD57, CD95 and HLA-DR. Cultured cells also expressed CD45RA. These cells lysed autologous and allogeneic HSV-infected lymphoblastoid cell line (LCL) targets via a non-major histocompatibility complex (MHC) restricted recognition pathway. Inhibition assays showed the mechanism of cytotoxicity to be calcium-dependent, granule exocytosis pathway, rather than the internal disintegration pathway. Cold target competition assays indicated that a common CTL population contributed to the recognition of autologous and allogeneic-infected targets. These effectors showed recognition of infected targets which was distinct from that of K562 cells. Non-MHC restricted lysis-associated molecule 2B4 (CD244) was upregulated on culturing and made a significant contribution to lysis of FcgR-bearing targets in a redirected killing assay. These findings suggest that CTL can recognize virally infected cells through a combination of non-MHC restricted mechanisms and may result in more efficient lysis than classical CD8 T cells.

Prevalence and clinical association of clonal T-cell expansions in Myelodysplastic Syndrome

“…49,52 CD244-deficient mice lack multiple effector functions and CD244-CD48 interactions produce more efficient lysis than classical CD8 þ T cells pathways. 53 Effector functions associated with CD244 activation in CD8 þ T cells include induction of granzyme B and perforin expression, rapid interferon (IFNg) production, and downregulation of a lymph node homing receptor, CCR7. We also found that the lymph node homing receptor, CD62L which is often co-expressed with CCR7, was under-represented in CD8 þ lymphocytes and on clonal T cells from MDS patients coincident with greater marrow lymphocyte expansion.…”

Activated Lymphocytes Secretome Inhibits Differentiation and Induces Proliferation of C2C12 Myoblasts

“…After 40 minutes centrifugation at 400× g at 18-20 °C, the lymphocyte layer was carefully removed and washed twice with RPMI-1640 media. Isolated lymphocytes (3x10 5 /well) were cultured in pre-coated flat-bottomed microwell plates with anti-CD3 (OKT3, 10 µg/ml, Cilag AG, Schaffhausen, Switzerland), as previously described [18]. Cells were grown in RPMI-1640 medium, supplemented with 10% (v/v) human AB serum and 1% penicillin/streptomycin at 37 ° C in 5% CO 2 .…”

Altered expression of signalling lymphocyte activation molecule (SLAM) family receptors CS1 (CD319) and 2B4 (CD244) in patients with systemic lupus erythematosus

“…For example, a number of studies revealed that an inability to signal via 2B4 due to a genetic defect in SAP may contribute to the pathogenesis of XLP [25][26][27]. Human 2B4 expression is up-regulated on CD8 + T lymphocytes raised in response to herpes simplex virus (HSV), which lysed infected cells more efficiently [28]. Soluble CD48 (ligand for 2B4) is detected at elevated levels in the plasma of patients with arthritis and lymphoid leukaemia [29].…”