Killer cell lectin-like receptor G1 (KLRG1) is a transmembrane glycoprotein with an extracellular C-type lectin-like domain and a cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM)1. KLRG1 plays an inhibitory role in human NK and T cells2 and is frequently used as a marker of cellular differentiation, with memory cells and highly differentiated end-stage cells having a significantly higher percentage of expression than differentiating cells2. Additionally, the proportion of CD8+ T cells expressing KLRG1 is age-related, increasing from ~ 40% of the CD8+ T cell pool in young adults to 90% in individuals over 65. KLRG1 is known to bind E-, N-, and R-cadherin1, 2. Cadherin interactions are generally involved in cell-to-cell adhesion and additionally, KLRG1/E-cadherin interactions are involved in immune control2.
2F1 was generated by immunizing Syrian hamsters with IL-2 activated NK (A-LAK) cells from B6 (H-2b) mice3. Popliteal lymph node cells were fused to murine myeloma P3X63Ag.8.653 cells and hybridomas screened for antibodies specific to A-LAK cells.
Antibody 2F1 was used to show that KLRG1 is indirectly upregulated by expression of MHC class I molecules in an interaction affected by class I-specific Ly49 inhibitory receptors and was also used to show that KLRG1 expression is modulated by SHP-1 3 .
Additionally, 2F1 was used to identify the KLRG1 mouse homolog and show that it is not expressed on mouse mast cells 4.