The incorporation of a heterologous S gene has resulted in altered tropism in vitro.

(A, B, E, F) Ex vivo TOCs, (C) CK cells and (D) Vero cells were inoculated with 10⁴ PFU or CD₅₀ equivalent dose of either (A-D) M41-K, Beau-R or M41K-Beau(S) or (E-F) of M41-K, 4/91 or M41K-4/91(S). (A, C, D, E) Supernatant was collected at 24-hour intervals and titrated on (A, C, D) CK cells or (E) in ex vivo TOCs. (B, F) The percentage ciliary activity was assessed at 24-hour intervals. Note: TOCs were inoculated in replicates of 10, and mock infected TOCs were inoculated with media only. (A–F) Each data point represents the average titre from three independent experiments with error bars representing SEM. Statistical differences, * p<0.05 and ** p<0.05 were assessed by Two-Way ANOVA followed by Tukey’s test for multiple comparisons. (B, F) Statistical differences identified were between all viruses and mock from 24 to 96 hpi; no differences were identified between the viruses. (A, C, D) Only statistical differences between M41K-Beau(S) and M41-K are displayed. Additional statistical differences are as follows: (C) M41-K vs Beau-R, 24 hpi and (D) M41-K vs Beau-R, 24–96 hpi.