retinoids ( retinol , retinal , retinoic acid , retinyl beta-glucuronide , and 13-cis retinoic acid ) and carotenoids ( beta-carotene and canthaxanthin ) were evaluated for their immunomodulatory effects on human peripheral blood t-lymphocyte subpopulations and natural killer ( nk ) cells .
C0035339
retinoids
C0040845
retinoic acid