Viable Borrelia burgdorferi Enhances Interleukin-10 Production and Suppresses Activation of Murine Macrophages Article (Web of Science)

abstract

  • ABSTRACT Although it is capable of eliciting strong innate and adaptive immune responses, Borrelia burgdorferi often evades immune clearance through largely unknown mechanisms. Our previous studies determined that infected interlukin-10 −/− (IL-10 −/− ) mice show significantly lower B. burgdorferi levels than wild-type (B6) mice and that IL-10 inhibits innate immune responses critical for controlling B. burgdorferi infection. To determine whether virulent B. burgdorferi preferentially enhances IL-10 production, we developed an in vitro coculture medium (RPMI.B) in which both B. burgdorferi and primary macrophages (Mφs) remain viable. B. burgdorferi grew at similar rates and was able to regulate expression of immunoreactive proteins with similar kinetics in RPMI.B and in traditional BSK medium; in contrast, B. burgdorferi cultured in conventional tissue culture medium (RPMI) rapidly lost viability. Coculture of viable B. burgdorferi in RPMI.B with Mφs resulted in more rapid and significant increases in IL-10 transcripts and secreted proteins than coculture with nonviable B. burgdorferi in RPMI, which corresponded with decreased production of proinflammatory cytokines. Addition of live B. burgdorferi to Mφs in RPMI.B also elicited substantially higher IL-10 levels than heat-killed bacteria elicited, confirming that increased IL-10 production was not inherent to coculture in RPMI.B. Transfer of supernatants from B. burgdorferi -stimulated Mφs into naïve Mφ cultures resulted in suppressed activation upon subsequent stimulation with different bacterial agonists, and this suppression was obviated by IL-10-specific antibody. In vivo analyses determined that murine skin samples exhibited substantial upregulation of IL-10 within 24 h of injection of B. burgdorferi . Together, these results suggest that viable B. burgdorferi can suppress early Mφ responses during infection by causing increased release of IL-10.

authors

publication date

  • 2008

webpage

published in

number of pages

  • 9

start page

  • 1153

end page

  • 1162

volume

  • 76

issue

  • 3