Induction of Pro- and Anti-Inflammatory Cytokines byBorrelia burgdorferiLipoproteins in Monocytes Is Mediated by CD14

Abstract

We previously showed that heat-killed Borrelia burgdorferi spirochetes and lipidated outer surface protein A (L-OspA) stimulated the in vitro production of interleukin-10 (IL-10) in peripheral blood mononuclear cells (PBMC) from uninfected humans and rhesus monkeys (G. Giambartolomei et al., Infect. Immun. 66:2691–2697, 1998). Here we demonstrate that uninfected human peripheral blood monocytes, but not B or T cells, are the cells that transcribe the IL-10 cytokine gene in response to heat-killed B. burgdorferi. B. burgdorferi similarly induced an upregulation of the IL-1β and IL-6 cytokine genes in monocytes and the production of IL-10 and IL-6 in culture supernatants of the human monocytic cell line THP-1. Purified L-OspA (but not unlipidated OspA [U-OspA] or U-OspC) also stimulated the production of both cytokines in THP-1 cells in a dose-dependent fashion, suggesting that acylation of the OspA protein molecule is required for the production of both anti- and pro-inflammatory cytokines in naive monocytes. A lipohexapeptide that contained the tripalmitoyl-modified cysteine motif (Pam3Cys-Hex) of B. burgdorferi lipoproteins but with an arbitrary peptide sequence had the same effect. Monoclonal antibodies (MAbs) MY4 and 60bca, both of which bind to CD14 and are known to block lipopolysaccharide (LPS)-mediated cytokine production, were able to block L-OspA-mediated IL-10 and IL-6 cytokine production. In contrast, MAb 26ic, which also binds to CD14 but does not block LPS function, failed to inhibit L-OspA-mediated cytokine production. These data suggest that activation of monocytes and production of both anti- and pro-inflammatory cytokines induced by lipoproteins proceeds via the CD14 receptor. LPS binding protein was not required for OspA-induced cytokine production. Our results demonstrate that pro- and anti-inflammatory cytokines induced by B. burgdorferilipoproteins in PBMC are produced by monocytes and that lipoprotein and LPS signaling pathways share at least the initial signaling event that involves the CD14 receptor.

Borrelia burgdorferiStimulates the Production of Interleukin-10 in Peripheral Blood Mononuclear Cells from Uninfected Humans and Rhesus Monkeys

“…High levels of the IL-10 cytokine were induced by lipidated OspA in uninfected human PBMC. This effect was dose dependent (16). Polymyxin B treatment did not abrogate this IL-10 production, regardless of whether the latter was induced by L-OspA or heat-killed spirochetes.…”

CD14 expression and Kupffer cell dysfunction in non‐alcoholic steatohepatitis: Superparamagnetic iron oxide‐magnetic resonance image and pathologic correlation

“…14 These cells express CD14, which is a receptor for a complex consisting of LPS and LPS-binding protein, on the surface of macrophages. [15][16][17] CD14 plays an important role in endotoxin signaling, and can mediate the effects of endotoxin as well as other receptors (i.e. CD11b/CD18 and toll-like receptor 4).…”

Dual Role of Interleukin-10 in Murine Lyme Disease: Regulation of Arthritis Severity and Host Defense

“…Recently, Giambartolomei et al have shown that heat-killed B. burgdorferi and OspA can stimulate IL-10 production in peripheral blood mononuclear cells from humans and rhesus monkeys in vitro (24). The main source of IL-10 in B. burgdorferi-stimulated human peripheral blood mononuclear cells was subsequently identified as the monocyte (23). Furthermore, we have shown that addition of physiologic amounts of IL-10 to macrophage cultures suppresses the production of OspA-induced TNF, nitric oxide, and IL-6 ( Fig.…”