In rats, a significant decrease in total leukocyte number and a significant fall in total numbers of T, B, and both T helper and T cytotoxic lymphocyte subsets were caused by repeated administration of CBD (IP) at a dose of 5 mg/kg.
The total numbers of NK and NKT cells that are involved in the primary, nonspecific antiviral, and antitumor immune response were not affected by this immunosuppressive effect. In contrast, the total and percentage of NKT cell numbers, and the percentage number of NK cells were shown to be increased by CBD administration. These findings indicate that repeated treatment with CBD suppresses specific immunity through decreasing T, B, T cytotoxic, and T helper cell numbers. Also, nonspecific antiviral and antitumor immune responses related to NK and NKT cells may be increased upon repeated treatment with CBD (Ignatowska-Jankowska et al., 2009).
GPR55 receptors are expressed by human macrophages. Stimulation of GPR55 in human macrophages can enhance lipid accumulation, block cholesterol efflux, and exhibit pro-inflammatory and pro-atherogenic properties. CBD can counteract these effects through blocking GPR55, proposing that CBD may be used as a therapeutic potential (Lanuti et al., 2015).
In the mouse collagen model of arthritis, inflammation was suppressed by CBD in a dose-dependent manner (Malfait et al., 2000).