Sulfur dioxide-induced lymphocyte defects in human peripheral blood cultures

Abstract

Human lymphocyte cultures were prepared from peripheral blood of healthy males by a standard technique utilizing phytohemagglutinin. Nine cultures were established in each of five experiments. One, designated control, was allowed to grow without interruption for 3 days. Each experimental culture received a single exposure to 100 cc of 5.7 ppm SO 2 in air by bubbling the gas through the culture medium at either 0, 1, 2, or 3 days of incubation. An additional four cultures received an identical amount of the same quality of air minus the SO 2 at each time interval. All cultures were harvested as smears and hypotonic spread preparations at 72 hours after treatment for 1 hour with colchicine and 3H-thymidine. Statistical analysis revealed significantly reduced cell growth (enlargement), DNA synthesis, and mitotic indices in the cultures exposed to sulfur dioxide at initiation of incubation compared to controls and air-treated cultures. In addition, chromosome abnormalities, mainly in the form of clumping, were observed in the SO 2-treated cultures. Lymphocyte damage as caused by sulfur dioxide exposure is offered as one explanation for the reduced immunological responses observed in laboratory animals after inhalation of the gas in vivo.