Receptor for four distinct ligands: The TNF superfamily members TNFSF14/LIGHT and homotrimeric LTA/lymphotoxin-alpha and the immunoglobulin superfamily members BTLA and CD160, altogether defining a complex stimulatory and inhibitory signaling network ( , ). Signals via the TRAF2-TRAF3 E3 ligase pathway to promote immune cell survival and differentiation ( ). Participates in bidirectional cell-cell contact signaling between antigen presenting cells and lymphocytes. In response to ligation of TNFSF14/LIGHT, delivers costimulatory signals to T cells, promoting cell proliferation and effector functions . Interacts with CD160 on NK cells, enhancing IFNG production and anti-tumor immune response . In the context of bacterial infection, acts as a signaling receptor on epithelial cells for CD160 from intraepithelial lymphocytes, triggering the production of antimicrobial proteins and pro-inflammatory cytokines (By similarity). Upon binding to CD160 on activated CD4+ T cells, down-regulates CD28 costimulatory signaling, restricting memory and alloantigen-specific immune response . May interact in cis (on the same cell) or in trans (on other cells) with BTLA  (By similarity). In cis interactions, appears to play an immune regulatory role inhibiting in trans interactions in naive T cells to maintain a resting state. In trans interactions, can predominate during adaptive immune response to provide survival signals to effector T cells  (By similarity).
(Microbial infection) Acts as a receptor for Herpes simplex virus 1/HHV-1.
(Microbial infection) Acts as a receptor for Herpes simplex virus 2/HHV-2.
Subcellular locations: Cell membrane
Widely expressed, with the highest expression in lung, spleen and thymus. Expressed in a subpopulation of B cells and monocytes . Expressed in naive T cells .