Cannabinoids

406 G.A. Cabral and A. Staab

Table 1.Distribution of cannabinoid receptors in the immune system

Cell type/tissue Species Receptor Reference

B lymphocytes Human CB 2 Galiègue et al. 1995

Carayon et al. 1998

T4 lymphocytes Human CB 2 Galiègue et al. 1995

T8 lymphocytes Human CB 2 Galiègue et al. 1995

Leukocytes Human CB 2 Bouaboula et al. 1993

Macrophages Human, mouse CB 2 Galiègue et al. 1995

Lee et al. 2001a,b

Microglia Rat CB 1 ,CB 2 Sinha et al. 1998

Waksman et al. 1999

Carlisle et al. 2002

Mononuclear cells Human, rat CB 2 Galiègue et al. 1995

Facci et al 1995

Mast cells Rat CB 2 Facci et al. 1995

Natural killer (NK) cells Human CB 2 Galiègue et al. 1995

Peyer’s patches Rat CBa Lynn and Herkenham 1994

Spleen Human CB 1 ,CB 2 Kaminski et al. 1992

Mouse, rat Munro et al. 1993

Galiègue et al. 1995

Facci et al. 1995

Lynn and Herkenham 1994

Thymus Human CB 2 Galiègue et al. 1995

Tonsils Human CB 2 Galiègue et al. 1995

Lymph nodes Rat CBa Lynn and Herkenham 1994

Cannabinoid receptor type not specified.

In addition to the identification of cannabinoid receptor mRNA in immune cells
(Fig.1),cognateproteinhasbeendemonstratedinratlymphnodes,Peyer’spatches,
and spleen (Fig. 2). Lynn et al. (1994) used a radiolabeled high-affinity cannabinoid
receptor ligand (i.e., [^3 H]CP 55,940) for in vitro binding and autoradiography and
found that specific cannabinoid receptor binding was restricted to components
of the immune system at peripheral sites. Cannabinoid receptor protein in the
immune system was found to be confined to B lymphocyte-enriched areas such as
the marginal zone of the spleen, cortex of the lymph nodes, and nodular corona
of Peyer’s patches. Galiègue et al. (1995), using anti-human CB 2 IgG, localized
CB 2 receptors within B lymphocyte-enriched areas of the mantle of secondary
lymphoid follicles in sections of human tonsil. Protein for the CB 2 receptor has
been identified also by immunohistochemistry in B lymphocyte-enriched areas of
the mantle of secondary lymphoid follicles in human tonsil sections (Bouaboula
et al. 1993). Carayon et al. (1998) employed immunopurified polyclonal antibody
to investigate the expression of CB 2 receptors in leukocytes and showed that
peripheral blood and tonsillar B cells were the leukocyte subsets expressing the