| Abstract: | The role of cell-mediated immunity in hamsters during treponemal infection appears to involve the activated macrophage. To date, studies have been hindered by the inability to confirm that macrophages exhibit enhanced treponemicidal activity at the infection site. We show that lipopolysaccharide and thioglycollate-treated animals, when inoculated with Treponema pallidum subsp. pertenue, exhibit enhanced clearance of these organisms compared with controls. Macrophages from these infected groups display an enhanced respiratory burst, as detected by NBT reduction, as well as a marked increase in C3b receptor-mediated ingestion activity. Significant changes in these parameters indicate that alterations in macrophage activation are occurring in the infected compartment. Thus the stimulatory agents apparently modify the host's immune responses to promote subsequent reduction of treponemal infection. In addition, hamster peritoneal macrophages demonstrate enhanced activation behavior as a result of exposure to at least two signals, which may be prerequisite for processing this organism efficiently. |
