Multiple Human Papillomavirus Types Replicate in 3A Trophoblasts

Human papillomavirus (HPV) are more prevalent in spontaneous abortions than elect abortions and preferentially infect the trophoblasts. Related to this, HPV type 16 has been shown to productively replicate in 3A trophoblasts in tissue culture. Extending these earlier studies, the described study addresses the issue whether other genital HPV types (11, 18, and 31) can replicate in trophoblasts. In determining this, HPV-11, 18, or 31 genomic DNAs were lipofected into 3A trophoblasts in culture, thus finding all three HPV types could de novo DNA replicate in 3A trophoblasts (Southern blot) and sequentially express their early and late genes as RNA (RT-PCR) and as protein (immunohistochemistry for L1). HPV-transfected 3A lysates from all three HPV types were also shown to contain HPV infectious units by infection of normal skin raft cultures and by neutralization by specific antibody. Furthermore, microarray analysis revealed the gene expression profile of normal keratinocytes (NK) was closer to 3A trophoblasts than to normal fibroblasts. Moreover, the critical HPV transcription factors AP-1 and Sp1 were found to be more highly expressed in 3A cells than NK. These findings suggest trophoblasts, like squamous epithelium, are broadly permissive for HPV, and some similarities in the gene expression repertoire of these two cell types are consistent with this. Finally, these data support our previous results that demonstrate the relationship between HPV infection of the trophoblast and spontaneous abortions.