To investigate the replication dynamics and cellular states of host cells with human T cell leukemia virus type 1 (HTLV-1) infection.

HTLV-1 positive cell line MT2 was co-cultured with HeLa cells for 4 to 36 hours to acquire the virus early infection model. Immunoblotting was used to detect HTLV-1 core protein p19, apoptosis-related proteins caspase-3/9 and autophagy-related protein LC3 at different time points. Real-time PCR was used to measure viral loads. Luciferase reporter gene assay was used to detect the enzymatic activities of caspase-3/7/9 and the transcriptional activities of 3′-LTR at different time points after co-culturing. Autophagosomes were analyzed by immunofluorescence after co-culturing. The HTLV-1 long terminal repeat reporter gene (pHTLV-1-LTR-luc) was transfected into HeLa cells by lipidosome 2000-mediated transfection and the luciferase activities at different time points were detected.

The HTLV-1 infection model was successfully constructed by co-culturing MT2 cells with HeLa cells in vitro. Viral load and transcriptional activity of the 3′-LTR gradually increased at 4 to 16 h after virus infection (P<0.01) and the viral load reached a steady state at 24 h. The expression of core protein p19 could be detected at 4 h after infection, decreased at 8 h and increased at 16 h, followed by reaching a steady state at 24 h. The enzymatic activity and cleaved protein of caspase-3/7/9 had no significant change at different time points after infection (P>0.05), but the proportion of LC3B/LC3A showed a gradual increasing trend with the persistent increase of autophagosomes (P<0.01).

Viral replication dynamics of HTLV-1 is closely related to autophagy in host cells.

Human T cell leukemia virus type 1; Replication dynamics; Apoptosis; Autophagy