Keyhole limpet hemocyanin immunotherapy of murine bladder cancer.

The current treatment of choice for superficial bladder cancer, bacillus Calmette-Guérin, has significant adverse side effects. We have compared two alternative immunotherapies--crude keyhole limpet hemocyanin (KLH) and Immucothel, a KLH modified for clinical use (Biosyn)--in an intralesional mouse model of bladder cancer (MBT2). Crude KLH required either immunization before tumor transplant or frequent intralesional therapy after transplantation to be effective. In addition, Immucothel required pre-immunization to be effective, and increasing the frequency and dosage of post-transplant immunization was not effective without pre-immunization. Preliminary investigations into the KLH-induced anti-tumor mechanism(s) suggest that natural killer cell activity may be involved. Both crude KLH and Immucothel appear to be effective immunotherapies of use in the treatment of transitional cell carcinoma.