Expression of herpes virus entry mediator on mononuclear cells of cord blood: LIGHT up-regulates CCR1 and ICAM-1 on monocytes

Cord blood mononuclear cells (CBMC) are responsible for neonatal host defense against microbial infections. Among them, monocytes and neutrophils are first-line of host defense cells in bacterial infections. Previously, we reported that herpes virus entry mediator protein (HVEM) ligation by its ligand, lymphotoxin-like inducible protein that competes with glycoprotein D for binding herpes virus entry mediator on T cells (LIGHT; TNFSF14), stimulates adult peripheral blood (PB) monocytes and neutrophils to increase their bactericidal activities. In this study, we investigated the role of HVEM on cord blood (CB) monocytes and neutrophils. HVEM expression was significantly lower on CB B- and T-lymphocytes than PB B- and T-lymphocytes. However, HVEM expression on CB monocytes and neutrophils was similar to PB monocytes and neutrophils. Moreover, LIGHT treatment to CB monocytes and neutrophils enhanced CC chemokine receptor 1 (CCR1) and intracellular adhesion molecule-1 (ICAM-1, CD54) expressions, which are used for cell migration during bacterial infections. These results suggest CB HVEM activation is important in neonatal host defense against bacterial infections.