Fig. 7. Inhibition of chemokine biological activity by gG. (A) Chemokine-induced calcium flux. The indicated amount of purified BHV-1 gG.His was pre-incubated with 75 ng of CXCL1 before addition to Indo-1-loaded U937 cells. Similarly, purified BHV-5 gG. His was pre-incubated with 75 ng of CCL3 before addition to Indo-1-loaded HeLa cells transfected with CCR5 and CXCR4. Intracellular calcium mobilization was measured by FACS analysis. (B) Chemokine-induced chemotaxis in a Transwell migration assay. The top panel shows the migration of human neutrophils in response to 100 ng/ml CXCL8 in the presence of supernatants, expressed as cell equivalents, from insect cells infected with a recombinant baculovirus expressing full-length EHV-1 gG. The middle panel shows chemotaxis of human neutrophils induced by 100 ng/ml CXCL1 in the presence of increasing doses of purified BHV-1 gG.His. The bottom panel shows migration of U937 cells in response to 100 ng/ml CCL3 in the presence of purified BHV-5 gG.His. Supernatants from AcNPV-infected insect cells or an irrelevant purified His-tagged VV protein (A40R.His) were used as negative controls. Leukocytes migrating in duplicate assays are expressed as the percentage (mean ± SD) of the total cells added or as the number of cells counted (mean ± SD) in four high powered fields.