Cell-mediated immune responses to transplanted tumors in mice chronically exposed to cigarette smoke.

C57BL and BALB/c mice were exposed to fresh cigarette smoke for 7-8 minutes per day for varying periods up to 30 weeks before subcutaneous or intratracheal inoculation of viable tumor cells. The growth rates of subcutaneous tumors in the mice exposed to smoke were significantly higher than those of controls and more lung metastases were noted. Enhanced tumor growth rates in the respiratory tracts of smoke-exposed mice were evidenced by the markedly increased death rates in these animals after the intratracheal inoculation of tumor cells. Increased tumor growth rates in mice that inhaled smoke were assoicated with depressed tumor-specific cytotoxic responses in both spleens and regional lymph nodes. Short-term exposure (10 wk) of mice to cigarette smoke resulted in decreased tumor growth rates concomitant with enhanced cytotoxic responses.