Table 2.

Opioid receptor expression in immune cells

Cell type	μ	δ	κ	Reference
T cell	CEM cell line, human CD4+ T cells	MOLT cell line, human cell line, murnie splenic T-cells,	MOLT cell line, human immature thymic T-cells, murine thymocytes and splenocytes	(Chuang et al., 1995) (Wick et al., 1996) (Sharp et al., 1998) (Ignatowski and Bidlack, 1998)
B cell	CEM cell line, Raji line	Human cell line	CEM cell line	(Chuang et al., 1995) (Gaveriaux et al., 1995) (Suzuki et al., 2001)
Dendritic cell	Human and murine primary DC	Human and murine primary DC	Murine DC	(Makarenkova et al., 2001) (Krist et al., 2002)
Macrophage / monocyte	Primary rat peritoneal mac., human and simean mono.	Human cell line	Macrophage-like murine cell line P388D1	(Chuang et al., 1995) (Sedqi et al., 1995) (Lopker et al., 1980) (Carr et al., 1991)
Neutrophil	Human granulocytes	Human granulocytes	Murine bone marrow neutrophils	(Lopker et al., 1980) (Falke et al., 1985) (Stefano et al., 1993) (Kulkarni-Narla et al., 2001)
Microglia	Human fetal microglia Murine microglia	Murine microglia	Human fetal microglia Murine microglia	(Chao et al., 1996) (Stiene-Martin et al., 2001)