Abstract
BACKGROUND: The concept of antibody dependent enhancement (ADE) of dengue virus (DENV) infection is a cornerstone of our current understanding of dengue pathogenesis, although some questions as to the mechanism remain, particularly in regards to the behavior of low and high passage virus isolates. This study utilized two low passage DENV 4 isolates and a laboratory adapted DENV 4 isolate to investigate the potential of low passage isolates to undergo ADE. RESULTS: Little or no ADE of infection was observed on day 2 post infection with low passage isolates, while high enhancement of infection was seen with the laboratory adapted virus. However, both of the low passage isolates showed high levels of infection (60-100%) by day 5 post infection. CONCLUSIONS: These results show that low passage DENV 4 viruses undergo ADE mediated infection, but that the process is significantly temporally delayed as compared to laboratory adapted DENV 4.