Tick Salivary Gland Extract Inhibits Killing of Borrelia afzelii Spirochetes by Mouse Macrophages

Salivary gland extract (SGE) from Ixodes ricinus ticks inhibited the killing of Borrelia afzelii spirochetes by murine macrophages. SGE also reduced the production of two major defense molecules of phagocytes, superoxide and nitric oxide. It is likely that the suppression of macrophage microbicidal mechanisms contributes to the inhibitory effect of tick saliva on the killing of B. afzelii spirochetes, thus facilitating the transmission of this important pathogen.