The family of T1/35 kDa proteins are encoded by the '35K' virulence gene of many poxviruses and are secreted from virus-infected cells. These proteins bind
CC-chemokines with high affinity and are termed viral chemokine inhibitor (vCCI). Viral CCI from various poxviruses share multiple stretches of sequence identity and eight conserved cysteine residues (1). The vaccinia virus (strain Lister) vCCI cDNA encodes a 258 amino acid (aa) protein with a putative 17 aa signal peptide (2). Vaccinia virus (strain Lister) vCCI shows greater than 90% aa sequence identity with vCCI from other orthopoxviruses and approximately 40% aa sequence identity with the leporipoxvirus T-1 proteins. vCCI binds with high affinity to many human, mouse, and rat CC-chemokines (1, 3-5). It binds to the same surfaces of these chemokines that are involved in chemokine receptor interactions (4-7). Some CC-chemokines utilize common binding surfaces on vCCI, while others interact with distinct sites on vCCI (8). vCCI inhibits CC-chemokine induced monocyte chemotaxis in vitro but does not block cellular effects induced by CXCL5/ENA-78, CXCL8/IL-8, or CXCL10/IP-10 (3-5). In vivo, vCCI restricts the infiltration of  immune cells into sites of inflammation (3, 9, 10) and also the CC-chemokine induced migration of arterial vascular smooth muscle cells (11).