Heat-inactivated serum is diluted 1:50–1:800 (depending on the expected potency of the serum) in phenol-free MEM supplemented with glutamax, 5% FBS, and Penicillin/Streptomycin and serially diluted in a 3-fold series (50 µL final volume). RSV-Renilla Luciferase virus was then diluted...