Integrins have no role in EHV-1 or EHV-4 entry into equine cells. PBMC (a) NBL-6 (b) or FHK (c) cells were incubated with anti-α4β7 MAb DATK32 or α4β1 MAb P4C2 for 1 h at RT, followed by incubation with Alexa fluor 488-labeled goat anti-mouse IgG for 1 h at RT. As controls, cells were incubated with irrelevant MAbs of the same IgG isotype. Integrin expression was determined by flow cytometry. (d) PBMC were preincubated with either α4β7 MAb DATK32 or α4β1 MAb P4C2 for 1 h at 4°C, followed by infection with recombinant viruses at an MOI of 5 for 2 h at 37°C. At 48 h pi, cells were washed and the percentage of infected cells was determined by flow cytometry. The rate of infection of parental viruses was set to 100%. All data represent the mean ± SD of three independent experiments.