Effects of NO2 on the response of baboon alveolar macrophages to migration inhibitory factor

Pulmonary alveolar macrophages (PAM) were obtained by lavage from baboons exposed for 6 mo to 2 ppm NO2 for 8 h/d, 5 d/wk, and the response of these cells to autologous migration inhibitory factor (MIF) was determined. PAM from two of three antigen-sensitized, NO2-exposed animals failed to respond to MIF derived from antigen-stimulated autologous lymphocytes. Similarly, PAM from three of the four NO2-exposed animals had diminished responsiveness to MIF obtained by phytohemagglutinin stimulation of their own lymphocytes. The altered responsiveness resulted from an effect on the macrophages and not on the lymphocytes used to prepare the MIF, as shown by the normal blastogenic responsiveness of the lymphocytes and the normal activity of the MIF thus produced on guinea pig peritoneal macrophages. These results demonstrate that inhalation of 2 ppm NO2 may have important subtle effects on pulmonary cells, which may result in altered immune capabilities within the lung.