DIFFERENTIAL VIRAL REPLICATION FOLLOWING IN-VITRO RESPIRATORY SYNCYTIAL VIRUS INFECTION OF MATCHED PAEDIATRIC PRIMARY BRONCHIAL AND NASAL EPITHELIAL CELLS

¹D. O’Donoghue, ²G. Skibinski, ²L. Heaney, ³U. Power, ²M. Shields. ¹Royal Belfast Hospital for Sick Children, Belfast, UK, ²Respiratory Research Group, Queen’s University, Belfast, UK, ³Department of Immunobiology, Queen’s University, Belfast, UK

Background: Respiratory syncytial virus (RSV) is the most commonly isolated virus causing acute bronchiolitis. It typically presents with rhinorrhea, followed in a proportion of children by lower respiratory tract signs. An in-vitro study demonstrated no difference in infectivity to rhinovirus in upper and lower epithelial cells.¹ Viral replication following RSV infection has not previously been studied in matched paediatric primary bronchial epithelial cells (PBEC) and primary nasal epithelial cells (PNEC).

Aims: To compare viral replication following in-vitro infection of matched paediatric PBEC and PNEC.

Methods: PBEC and PNEC were obtained from paediatric subjects by non-bronchoscopic bronchial and nasal brushings following the induction of anaesthesia for elective surgical procedures. The matched PBEC and PNEC were cultured to passage three and were infected with a wild-type RSV A at a multiplicity of infection of 0.1 and also with mock infection. Cell lysates were collected in duplicate at regular post-infection time points up to 96 h post-infection and were used to measure viral replication. Viral replication was determined by serial dilutions to look for evidence of cytopathic effect and expressed as log 50% tissue culture infective doses (TCID₅₀)/ml. Repeated measures analysis of variance was used for statistical analysis of viral replication over the postinfection time course.

Results: Matched PBEC and PNEC were obtained and cultured from six paediatric subjects with a median age of 5.2 years (range 2–8 years). PNEC supported significantly greater wild-type RSV A replication than PBEC (p<0.01) over the experimental time course.

Conclusion: There is greater viral replication …