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Title: T-cell activation in pulmonary lymph nodes of mice exposed to ozone

Journal Article · · Environ. Res.; (United States)
OSTI ID:6997358

Groups of Cd-1 female mice were exposed to ozone at 0.3, 0.5, and 0.7 ppm, 20 hr per day, 7 days per week for 1-28 days. The effect of ozone exposure on lymphoid cells was determined by studying mediastinal lymph nodes at various times of exposure. It was found that lymphocyte numbers underwent a dose-dependent, four-phased change:cellular depletion (Days 1-2), followed by rapid hyperplasia (Days 3-4), incremental cell number reduction (Days 5-7), and a subsequent subacute phase of elevated lymphocyte numbers (Days 8-28). Using tritiated thymidine it was determined that cells underwent a rapid burst of division by Day 3 of exposure and that mitosis subsequently declined to near baseline values by 2 weeks of exposure. Autoradiographic analysis of histologic sections revealed that the paracortical T-cell areas of the nodes were particularly involved. In addition to the increase in thymidine uptake, several morphologic changes were evident in affected cells. By comparison, the B cells from ozone-exposed animals were virtually unaffected with respect to cell division or morphological alterations. Prior treatment of ozone-exposed animals with a monoclonal antibody that is cytotoxic for T cells eliminated the hyperplastic response. Immunologic aspects of T-cell reactivity were studied. T-cell responsiveness to mitogenic stimulation with concanavalin A showed little alteration during the first days of exposure; however, by Day 14 an increase in reactivity was observed. This change indicated that functional lymphocyte stimulation occurred during ozone exposure.

Research Organization:
General Motors Research Labs., Warren, MI
OSTI ID:
6997358
Journal Information:
Environ. Res.; (United States), Vol. 38:2
Country of Publication:
United States
Language:
English