<p><b>(A) The rapid method for MV titration is based on a single infection cycle.</b> Vero cells were inoculated with MV-Halle strain for 6 hours. Then, they were washed with PBS to eliminate residual virus. Medium supplemented or not with 0.1 mg/ml of the fusion inhibitory peptide (FIP) was then added. At 18 h.p.i., cells were analyzed by flow cytometry and similar titers were found in both cases (i.e. with and without FIP) (Compare “a” 7.86 Log IU/ml and “b” 7.92 Log IU/ml. As a control for FIP efficiency, its addition just before the virus inoculation completely prevented MV infection “c”. <b>(B) Validation of estimated virus cycle duration as reading time for titration.</b> Similar titers were obtained after inhibition of secondary infection by anti-measles serum. Vero cells were infected with MV-eGFP for 6 hours, then washed with PBS and further incubated in the presence “a” or absence “b” of a potent neutralizing antiserum. “c” - neutralization efficiency of the anti-serum upon addition to the virus inoculum prior to infection. Note for the highest inoculum volume, a small GFP background signal was detected due to the low amount of GFP embarked into the input virus particles.</p
