Keyhole limpet hemocyanin: an effective adjunct against melanoma in vivo

BACKGROUND: We have previously demonstrated the potent in vitro antiproliferative effects of keyhole limpet hemocyanin (KLH) against melanoma. Our prior studies directed us to hypothesize that KLH would be effective in vivo against melanoma, alone and in combination with conventional immunotherapy. METHODS: Mice were inoculated with 2 x 10(7) HTB68 cells and randomized to 6 groups. Treatment groups consisted of control, KLH 200 microg, alpha interferon (AIFN) 1000 IU, interleukin-2 (IL-2) 5000 IU, KLH + AIFN, and KLH + IL-2. RESULTS: KLH + IL-2 exhibited the greatest reduction in tumor volume (30%) as compared to control (P = .014), followed by KLH + AIFN (28%, P = .031). Singly treated animals had less tumor inhibition: IL-2 (30%, P = .022), KLH (18%, not significant), and AIFN (16%, not significant). CONCLUSIONS: KLH augments the effects of AIFN, one of the standard immunotherapeutic agents against melanoma in vivo. Further in vivo and early clinical studies into the effects of KLH as both a single and combined agent are warranted.