Signaling pathways involved in foreign antigen expression by a recombinant vaccinia virus (89.38)

Abstract

Abstract BACKGROUND: Vaccinia virus (VV) was used as a live vaccine to eradicate smallpox and has in recent years received considerable attention for the development of live vaccine vectors due to its broad host range and ability to express a variety of foreign antigens, which can induce humoral and cellular immunity against virus infections. However, little is known about the cellular signaling pathways involved in the foreign antigen expression by a recombinant VV. METHODS: Using a recombinant EGFP-VV, we studied four cellular signaling pathways, PI3K, p38 MAPK, JNK, and ERK, by assessing EGFP production in infected human peripheral blood monocytes and monocyte-derived dendritic cells (MDDCs). RESULTS: EGFP expression was inhibited significantly in both monocytes and MDDCs infected with EGFP-VV by blocking the PI3K, p38 MAKP, and JNK pathways by specific inhibitors LY294002, SB203580, and SP600125, respectively. PI3K was the most critical pathway involved in antigen expression by VV-infected cells, whereby LY294002 (25 uM) exhibited 90.1% decrease of EGFP expression compared to non-inhibitor-treated control (DMSO). Whereas, at the same concentration (25 uM), SB203580 and SP600125 inhibited only 69.3% and 30.4% of EGFP expression, respectively. Inhibition of the ERK pathway by PD098059 did not alter EGFP expression. CONCLUSIONS: VV is able to infect APCs and efficiently express inserted gene(s) through cellular signaling pathways of PI3K, p38 MAPK, and JNK, but not ERK. ACKNOWLEDGMENTS: This work was supported by University of Washington CFAR (Award AI 27757), Hawaii Community Foundation (Award 20061466), UH INBRE, and HACTU grant from NIAID (A134853).