HEP (2005) 168:385–423
©cSpringer-Verlag 2005
Effects on the Immune System
G.A. Cabral ()·A.Staab
Department of Microbiology and Immunology, Virginia Commonwealth University,
School of Medicine, 1101 E. Marshall St., Richmond VA, 23298-0678, USA
[email protected]
1Introduction.................................... 386
2 Cannabinoids and the Immune System ..................... 388
2.1 EarlyStudies.................................... 388
2.2 EffectsontheImmuneSystemUsingInVivoModels.............. 389
2.3 EffectsontheImmuneSystemUsingInVitroModels.............. 391
2.3.1EffectsonMixedCellPopulations ........................ 391
2.3.2 Effects on Mononuclear Cells, Macrophages, and Macrophage-Like Cells... 392
2.3.3EffectsonBLymphocytes............................. 394
2.3.4EffectsonTLymphocytes............................. 395
2.3.5EffectsonNaturalKillerCells .......................... 396
2.4 EffectsonCytokines ............................... 397
3 Cannabinoids and Infections........................... 399
3.1 InVitroInfections................................. 399
3.2 InVivoInfections ................................. 400
4 Effects of Marijuana and Cannabinoids on Human Health........... 402
4.1 Effects Related to Infections
OtherThanwiththeHumanImmunodeficiencyVirus ............. 402
4.2 Effects Related to Infection with Human Immunodeficiency Virus and AIDS. 403
5 Distribution of Cannabinoid Receptors in the Immune System ........ 405
5.1 NativeDistribution ................................ 405
5.2 DistributioninCellLines............................. 408
6 ModeofActionintheImmuneSystem...................... 408
6.1 ExogenousCannabinoids............................. 408
6.2 EndogenousCannabinoids(Endocannabinoids) ................ 410
7 CannabinoidsasImmuneTherapeuticAgents ................. 411
8 Summary and Conclusions............................ 414
References ........................................ 414
AbstractMarijuana and other exogenous cannabinoids alter immune function
and decrease host resistance to microbial infections in experimental animal mod-
els and in vitro. Two modes of action by which∆^9 -tetrahydrocannabinol (THC) and
other cannabinoids affect immune responses have been proposed. First, cannabi-
noids may signal through the cannabinoid receptors CB 1 and CB 2. Second, at sites