A technique for intensifying BCG sensitivity.

Sensitization to BCG (Bacille Calmette-Guérin) appears to be more effective when it is carried out at the site of a delayed hypersensitivity challenge reaction to DNCB (1-chloro, 2,4-dinitrobenzene) than when it is carried out at unchallenged sites in non-sensitized animals. The effectiveness of BCG sensitization was determined by measurement of the intensity of the PPD (Purified Protein Derivative of tuberculin) 24-hour skin test. Possible mechanisms for this phenomenon and its implications for cancer immunotherapy are considered.