The migration of bronchoalveolar macrophages into hilar lymph nodes.

The migration of bronchoalveolar macrophages ( BAMs ) into hilar lymph nodes ( HLNs ) was investigated in order to assess their potential importance in pulmonary immune responses. 51Chromium- or 111Indium-labeled broncholaveolar cells ( BACs ) or purified BAMs were inoculated into the tracheas of syngeneic guinea pigs, and the number of cells that reached HLN at 24-72 hours was estimated by 1) measuring the cell-associated radioactivity in HLN and 2) counting the radiolabeled cells in autoradiographic preparations. It was determined that 400-2900 BAM/10(7) inoculated BACs or BAMs reached the HLNs within a 3-day period. From this data, it was calculated that in a normal animal as many as 8700 BAMs might reach HLNs daily. These migratory phagocytes are potentially important in facilitating the systemic spread of macrophage-resistant intracellular organisms from the lung. Furthermore, following phagocytosis and killing of microorganisms in the alveolus, BAMs might migrate to HLNs and present antigen to stimulate a primary immune response.