Sindbis virus replication in vertebrate and mosquito cells: an interpretation.

This paper summarizes recent comparative studies of Sindbis virus (SV) replication in cultured Aedes albopictus (A. albo) or (A. aegypti (A. aeg) and BHK21 or chick embryo (CEF) cells. 1. Viral growth kinetics and yields are similar in A. albo cells at 28 degress C and in vertebrate cells at 37 degrees C. A. albo exhibit no CPE and yield persistenetly infected cultures. 2. SV grown in A. albo cells lacks sialic acid but is antigenically and in terms of particle/PFU or particle/HAU ratios equivalent to SV derived from vertebrate cells. The contrast to VSV in the latter respect is discussed. 3. SV from persistently infected A. albo or A. aeg cells is temperature-sensitive, thermolabile, and produces small plaques. Partial characterization of these mutants, of RNA associated with their replication, and their high reversion rate to ts+ upon serial undiluted passage in GHK21 cells are presented. 4. Hostdependent differences in the generation of defective-interfering (DI) SV particles and of low molecular weight viral RNA species have been observed upon undiluted serial passages in BHK21 and CEF. In contrast, serial passage in A. albo cells appears not to produce DI particles or small RNA species nor do these cells "recognize" as such DI particles from BHK21 cells. 5. Possible implications of these observations fro the natural life cycle of arthropod-borne togaviruses are discussed.