Evaluation of the C6/36 Aedes albopiatus Cell Line as a Substrate for Dengue Virus Growth

BACKGROUND ~ Difficulty is often encountered in attempting to raise infectivity titers of newly isolated dengue virus strains by repeated passage in either LLCMk2 cells or suckling mouse brain (SMB)o Recently, a new mosquito cell line, the C6/'36 Aedes az'bopiatus ce111ine (1), was developed with the express goal of increased sensitivity and yield specifically for dengue viruses. This line was del:ived by cloning A" aZbopiatus (Singh) cells in media containing antiChikungunya antibody in order to circumvent problems with chronic chikungunya virus infection encountered in other mosquito cell lines. A clone of cells (clone 6) which produced the highest yield of dengue viruses compared to other clones was then selected; this clone was then recloned and the most sensitive sub-clone (C6/36) selected to start the line 0 The C6/36 cell line is reported to sho~7 a cytopathic response to dengue virus infection~ and may permit virus yields sufficiently high to allow for virus identification by the plaque I.'eductj.on neutralization (PRNT) methodo We elected to test the line using suck1irLg mouse brain seeds of prototype dengue-l~ -2, -3, and -4 viruseso To investj.gate if the line was also sensitive to virus with passage histories other t:han suckling mouse brain, we also test;ed a D2 mosquito passage seed and a deng\;!e type 2 LLC-Mk2 tissue culture seedo