IL10 and Lyme disease: Primary MØs derived from mouse lines known to develop either severe (C3H/HeN; C3H) or mild (C57BL/6; B6) Lyme disease during Bb infection showed that B6 MØs display a significantly greater IL-10 response to OspA lipoprotein than C3H MØs, and that addition of physiologic levels of IL-10 to OspA-stimulated C3H MØs reduced their production of proinflammatory cytokines to levels observed in B6 MØs, suggesting these differences in IL-10 production might influence the severity of Lyme disease [37,38].