title: PLAQUE ASSAY PROCEDURE FOR COLORADO TICK FEVER VIRUS.
abstract: Deig, E. Frank (University of California, Berkeley), and H. M. S. Watkins. Plaque assay procedure for Colorado tick fever virus. J. Bacteriol. 88:42-47. 1964.-A reproducible plaque assay procedure is described for the quantitation of Colorado tick fever virus in a cell line established from embryonic hamster tissue. Under the best conditions, plaques approximately 4 mm in diameter were formed after incubation at 37 C of 4 to 6 days. Several environmental variables in the procedure were studied. Efficiency was increased markedly by combining the virus during adsorption with serum proteins, and by carrying out this step at 25 C rather than at 37 C. The overlay medium used contained metabolites which promoted cell viability for periods greater than 1 week, and allowed plaques to develop. Plaque formation was relatively insensitive to a variation in pH between 7.1 and 8.1 (with optimal concentrations of bicarbonate). However, plaque development was inhibited with medium containing greater than 0.22% bicarbonate (at optimal pH), or when the initial pH was less than 7.0.
mesh_terms: D000327:Adsorption; D000818:Animals; D001103:Arboviruses; D001681:Biological Assay; D002460:Cell Line; D003122:Colorado tick fever virus; D006224:Cricetinae; D012106:Research; D046509:Tissue Culture Techniques; D014776:Virus Cultivation
keywords: ARBOVIRUS; EXPERIMENTAL LAB STUDY; TISSUE CULTURE; VIRUS CULTIVATION