Effects on rat lung immunity by acute lung exposure to benzo(a)pyrene.

This study describes the effect of intratracheal instillation of benzo(a)pyrene (BaP) on immunological responses in the lung-associated lymph nodes, cervical lymph nodes, and spleen after deposition of 10(8) sheep red blood cells (SRBC) in the lung or peritoneal cavity of rats. An increased number of anti-SRBC antibody-forming cells was observed in the lung-associated lymph nodes when rats were immunized simultaneously with BaP installation. A suppression in the number of anti-SRBC antibody-forming cells occurred when SRBC were given intratracheally 4 or 7 days after BaP. The effects of the BaP appeared to be on the function of the cells in the lung-associated lymph nodes rather than due to changes in the exposed lung. BaP-induced changes in antigen handling or in regulatory populations of immune cells in the lung-associated lymph nodes may be responsible for the immune alterations observed.