[F3, a fractionated extract of Astragalus membranaceus, potentiates lymphokine-activated killer cell cytotoxicity generated by low-dose recombinant interleukin-2].
Success with rIL-2 immunotherapy of human cancer appears to depend on the administration of high doses which are frequently associated with excessive toxicity. Future use of rIL-2 will require certain modifications based on the use of lower doses of rIL-2 without significant loss of antitumor efficacy. The authors tested in vitro the possibility of potentiating the activity of rIL-2 in terms of LAK cell generation. The authors hypothesized that co-incubation of LAK cell precursors with a Chinese herbal extract (F3) of Astragalus membranaceus (an immune modulator currently under study in the authors' laboratory), along with a low concentration of rIL-2 would generate levels of LAK cell activity equivalent to those generated by high concentrations of rIL-2 alone. The authors found: (1) a 10-fold potentiation of rIL-2 activity manifested by tumor cell killing activity of 80% resulting from LAK cell generation with F3 plus 100 u/ml of rIL-2 versus 76% generated by 1000 u/ml of rIL-2 alone; (2) a significant reduction in the number of effector LAK cells required for equicytotoxic reaction following LAK cell generation with F3 plus rIL-2 compared to rIL-2 alone. The authors conclude that potentiation of antitumor activity mediated by rIL-2 in low concentrations is possible by the concomitant use of another immune modulator such as Astragalus membranaceus.
Chu
D
D
Cancer Institute and Hospital, Chinese Academy of Medical Sciences, Beijing.
Sun
Y
Y
Lin
J
J
Wong
W
W
Mavligit
G
G
D027885:Astragalus propinquus; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D006801:Humans; D007376:Interleukin-2 / Q000276:immunology*; D015979:Killer Cells, Lymphokine-Activated / Q000276:immunology*; D008545:Melanoma / Q000473:pathology; D014407:Tumor Cells, Cultured / Q000187:drug effects
D004365:Drugs, Chinese Herbal; D007376:Interleukin-2