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! I I I I I I I I I I I I I I I I I AUTHOR: THOMAS, WAYNE R., PATRICK G. HOLT, AND DAVID KEAST DATE: 1973 TITLE: CELLULAR IMMUNITY IN MICE CHRONICALLY EXPOSED TO FRESH CIGARETTE SMOKE. CITATION: ARCH ENVIRON HEALTH 27:372-375 (1973) STUDY DESIGN: Groups of C57 Black mice were exposed on weekdays to fresh cigarete smoke for 5, 15,25 and 35 weeks, The phytohemagglutinin (PHA) responsiveness of the lymph node, spleen and peripheral blood lymphocytes of individual mice was determined by a micromethod measuring the incorporation of 3H-6-hyymidine into DNA at various concentrations of PHA-P. RNDINGS/RESULTS: The PHA responsiveness of lymphocytes recovered from the blood and spleen of exposed mice exhibited similar changes throughout the experimental period. After 5 weeks of smoke exposure, the response was depressed in both organs. At weeks 15 and 25, a transitory recovery was noted. By the 35~h week of exposure, the peak response in both organs differed from that in age- matched controls. However, only the peak response in the blood was significantly depressed. The lymph node cells displayed an enhanced response to PHA after 5 week of smoke exposure, but after 15 weeks the lymphocytes responded to only high concentrations of PHA. The response after 35 weeks was again markedly depressed. CONCLUSIONS/COMMENTS: The ultimate result of 35 weeks of smoke exposure was a decrease in pHA responsiveness of lymphocytes, especially in the regional lymph nodes of the respiratory system. The similarity found in the behavior of lymphocytes from the blood and spleen reflects not only the circulatory nature of the PHA responsive cell, but also the systemic effect of prolonged exposure to cigarette smoke.