Human papillomavirus type 31 uses a caveolin 1- and dynamin 2-mediated entry pathway for infection of human keratinocytes

Authors:
Smith JL, Campos SK, Ozbun MA
In:
Source: J Virol
Publication Date: (2007)
Issue: 81(18): 9922-31
Research Area:
Cancer Research/Cell Biology
Dermatology/Tissue Engineering
Cells used in publication:
HaCaT
Species: human
Tissue Origin: dermal
Platform:
Nucleofector® I/II/2b
Abstract
Papillomaviruses are species specific and epitheliotropic DNA viruses that cause tumors in their natural hosts. Certain infections with genital human papillomavirus (HPV) types are causally related to cervical cancer development. Most papillomaviruses are thought to infect cells via a clathrin-dependent pathway; yet no studies have determined the entry route in permissive host epithelial cells. Employing fluorescently labeled and native virions, we tested the effects of dominant negative and biochemical inhibitors of cellular endocytosis pathways. Infections of human keratinocytes, a natural host cell type for HPVs, were assessed visually and by infectious entry assays. We found that HPV type 31 (HPV31) entry and initiation of early infection events requires both caveolin 1 and dynamin 2 and occurs independently of clathrin-mediated endocytosis. Treatment with chlorpromazine and filipin had opposing effects on HPV31 and HPV16 infection. HPV31 entry was remarkably slow, with a half time of approximately 14h, whereas the entry half-time of HPV16 was 4h. Consistent with a caveolae-mediated entry pathway for HPV31, the virions associated with detergent-resistant lipid rafts. During a 16-hour microscopic tracking of HPV31 and HPV16 virions, no colocalization of the two viral types was observed. These data suggest that HPV31 and HPV16 virions use distinct routes for host epithelial cell entry.