The Important Role of Lipid Raft-Mediated Attachment in the Infection of Cultured Cells by Coronavirus Infectious Bronchitis Virus Beaudette Strain

Guo, Huichen; Huang, Mei; Yuan, Quan; Wei, Yanquan; Gao, Yuan; Mao, Lejiao; Gu, Lingjun; Tan, Yong Wah; Zhong, Yanxin; Liu, Dingxiang; Sun, Shiqi

The co-translocation of IBV E protein with lipid rafts on the cellular membrane suggested that lipid rafts are involved in IBV infection. To investigate whether lipid rafts are involved in IBV release, cell supernatants and total lysates after IBV infection with or without MβCD treatment were collected to detect viral proteins with specific antibodies. As shown in Fig 3A, IBV N protein was detectable in whole cell lysates (WCL) until 12 hpi. Notably, the expression levels of IBV N protein in the WCL and the supernatants significantly decreased after MβCD treatment compared with the control, especially at 12-18 hpi in the WCL. Moreover, the ratio of IBV N protein in the WCL and supernatants was similar for treated and untreated infected cells. This result indicated that MβCD treatment did not influence the release of virions to the supernatant. Similarly, Mevastatin treatment also significantly and simultaneously decreased viral N protein levels both in the WCL and the supernatants. These results suggested that Mevastatin and MβCD affected IBV replication in the cytoplasm and reduced the number of viral particles released into the supernatant. Additionally, lipid raft disruption did not influence the release