The use of Toxorhynchites splendens for identification and quantitation of serotypes contained in the tetravalent live attenuated dengue vaccine.

Assurance of identity and quantity is an indispensable part of quality control in the manufacture of vaccines. Dengue-1 PDK13, dengue-2 PDK53, dengue-3 PGMK30F3 and dengue-4 PDK48 in the live attenuated tetravalent dengue vaccine were assayed by identification and quantitation in a mosquito system (Toxorhynchites splendens). Each serotype of dengue virus was identified by dengue specific monoclonal antibodies in the indirect fluorescent antibody test. Virus content was estimated by calculating the 50% mosquito infectious dose (MID50). Differences from 0 to +/-0.5 log10 were observed between the original monovalent titer and that from the blend which showed no significant difference at 95% confidence limit (P < 0.05). This result indicates that there is no interference between dengue serotypes in mosquitoes infected by intrathoracic inoculation with the virus mixture. It can be also concluded that this mosquito system can be used as an effective measure for infectivity titration of each component in the tetravalent dengue vaccine.