Anti-CD62L Antibody [LT-TD180] (PE) (A85810)

Microsatellite instability (MSI-H) induced by defects of the DNA mismatch repair system results in insertion or deletion of single nucleotides at short repetitive DNA sequences. About 15% of sporadic and approximately 90% of hereditary nonpolyposis colorectal cancers display MSI-H. When affecting coding regions, MSI-H results in frameshift mutations and expression of corresponding frameshift peptides (FSPs). Functional tumor promoting relevance has been demonstrated for a growing number of genes frequently hit by MSI-H. Contrary, immune reactions against FSPs are involved in the immune surveillance of MSI-H cancers. Here, we provide conclusive data that the (-1) frame of U79260(FTO) encodes an HLA-A0201-restricted cytotoxic T cell epitope (FSP11; TLSPGWSAV). T cells specific for FSP11 efficiently recognized HLA-A0201((pos)) tumor cells harboring the mutated reading frame. Considering the exceptionally high mutation rate of U79260(FTO) in MSI-H colorectal carcinoma (81.8%), this recommends that FSP11 be a component of future vaccines.

NKp80, an activating homodimeric C-type lectin-like receptor (CTLR), is expressed on essentially all human natural killer (NK) cells and stimulates their cytotoxicity and cytokine release. Recently, we demonstrated that the ligand for NKp80 is the myeloid-specific CTLR activation-induced C-type lectin (AICL), which is encoded in the natural killer gene complex (NKC) adjacent to NKp80. Here, we show that NKp80 also is expressed on a minor fraction of human CD8 T cells that exhibit a high responsiveness and an effector memory phenotype. Gene expression profiling and flow cytometric analyses revealed that this NKp80(+) T-cell subset is characterized by the coexpression of other NK receptors and increased levels of cytotoxic effector molecules and adhesion molecules mediating access to sites of inflammation. NKp80 ligation augmented CD3-stimulated degranulation and interferon (IFN)gamma secretion by effector memory T cells. Furthermore, engagement of NKp80 by AICL-expressing transfectants or macrophages markedly enhanced CD8 T-cell responses in alloreactive settings. Collectively, our data demonstrate that NKp80 is expressed on a highly responsive subset of effector memory CD8 T cells with an inflammatory NK-like phenotype and promotes T-cell responses toward AICL-expressing cells. Hence, NKp80 may enable effector memory CD8 T cells to interact functionally with cells of myeloid origin at sites of inflammation.