Cultivation of mosquito cell lines in serum-free media and their effects on dengue virus replication.

Seven mosquito cell lines from five species (Aedes aegypti, Ae. albopictus, Ae. pseudoscutellaris, Culex tarsalis, and Toxorhynchites amboinensis) were adapted to three kinds of serum-free media (SEM), which were composed of equal volumes of tryptose phosphate broth and of either Leibovitz (L15) medium, Eagle's minimum essential medium, or Medium 199 with Hanks' salts. Population growth rates of the cells cultivated in the SMFs were generally slower than those of original cell cultures maintained in conventional media containing bovine sera. A karyological study showed a significant shift to heteroploidy in two of the four cell lines examined. Four SMF-adapted sublines were compared with parental cultures for replication of dengue viruses. Ae. aegypti RML-12, Ae. albopictus C6/36, Ae. pseudoscutellaris AP-61, and Tx. amboinensis TRA-171 demonstrated different levels of alteration in virus replication ranging from lower titers (as in Ae. albopictus C6/36) to comparable or higher titers (as in Ae. aegypti RML-12) when they were simultaneously inoculated with four dengue serotypes.