Characteristics of Sindbis virus temperature-sensitive mutants in cultured BHK-21 and Aedes albopictus (Mosquito) cells

Abstract

A number of the temperature-sensitive mutants of Sindbis virus originally isolated and characterized by Burge and Pfefferkorn (1966, 1968) were reexamined for their abilities to grow and complement one another in cultured BHK-21 and Aedes albopictus (mosquito) cells. The response of the mutants to conditions of high and low temperature was similar in cultured cells of both the vertebrate and invertebrate hosts. Complementation experiments in BHK-21 cells produced growth patterns similar to those described by Burge and Pfefferkorn for chicken embryo fibroblast cells (1966) and placed the mutants into six nonoverlapping complementation groups. When examined in the cultured mosquito cells, only three of the nine mutants used in this study demonstrated complementation under a variety of experimental conditions. Homologous interference experiments demonstrated that the unusual patterns of complementation obtained in the A. albopictus cells did not result from an inefficient infection of the invertebrate cells by the mutants.

Role of extracellular virus on the maintenance of the persistent infection induced in Aedes albopictus (mosquito) cells by Sindbis virus

“…3). The higher multiplicity of infection was used to be certain that all of the cells were infected, even though in a previous study we demonstrated that all of the cells in a mosquito culture could be infected by 50to 100-PFU multiplicities under the conditions used for infection in this study (12).…”

“…Research Unit, New Haven, Conn.) and were cultured in the medium of Mitsuhashi and Maramorosch (9) as described previously (12). BHK-21 cells were provided by Peter Faulkner (Queens University, Ontario, Canada) and were grown in Eagle medium (4) supplemented with 10% calf serum.…”

“…The heat-resistant strain of Sindbis virus, which serves as wild-type virus in this laboratory, as well as the temperature-sensitive mutant ts-20 were provided by Elmer Pfefferkorn (Dartmouth Medical School, Hanover, N.H.). Virus stocks were prepared and titrated in BHK cells as described previously (12).…”

“…Ability of antiserum-treated and untreated cells to exclude superinfecting Sindbis virus. We have previously demonstrated that the ability of a culture of infected mosquito cells to exclude a second superinfecting virion can be used as an indication of the percentage of the cells that were infected by the first virus (12). The exclusion of the superinfecting virion is complete when the culture is completely infected with the first virus.…”

“…The 'ability of the antibody-treated and untreated, persistently infected cells to exclude superinfecting Sindbis virus was tested by reinfecting the cultures with the Sindbis mutant ts-20. ts-20 is particularly suitable for an experiment of this type because of its low reversion index (12) and because our isolate of this mutant produces a plaque that is easily distinguishable, morphologically, from that produced by virus released from the persistently infected cells. The result of this experiment is shown in Table 1.…”