Research Article
Jie Xue, Nai-Wei Kuo, Megan S
Abstract
vMIP-II (viral macrophage inflammatory protein-II) is a chemokine analog expressed by human herpesvirus-8 that has the unique ability to bind multiple human chemokine receptors, including CCR5 and CXCR4, representative receptors of two major chemokine subfamilies. This broad binding ability gives vMIP-II powerful anti-inflammatory properties, which have been demonstrated in vitro and in vivo. In addition, vMIP-II is of great interest due to its ability to inhibit HIV infection by both major HIV strains: R5 (strains that enter the host cell using CCR5 as a co-receptor), and X4 (strains that use CXCR4). We have made a vMIP-II variant, “5P12-vMIP-II” in which the N-terminal amino acids of vMIP-II have been replaced by 10 amino acids that have been shown to greatly enhance the anti-HIV potency of the chemokine RANTES for R5 HIV strains. This 5P12-vMIP-II is shown by NMR to be fully folded and similar in structure to wild type vMIP-II. Both vMIP-II and 5P12-vMIP-II showed the ability to inhibit multiple strains of HIV, including several R5 strains and an X4 strain. While the 5P12 N-terminus did not improve the potency of the protein, our results suggest that vMIP-II does not bind CCR5 in the same way as human chemokines. Rather, vMIP-II has sacrificed some binding ability to particular chemokine receptors in order to obtain the ability to bind a broader array of receptors.