Plaque assay of rickettsiae in a mammalian cell line.

Plaque assay of African Horse-Sickness Virus in African Green Monkey Kidney Cell Line

Plaque formation by strains of spotted fever rickettsiae in monolayer cultures of various cell types.

Some strains of spotted fever rickettsiae could be distinguished by their ability or inability to form plaques in monolayer cultures of various mammalian and avian cell types.

Fever and Scrub Typhus Rickettsiae

The rickettsiae have always been difficult to study because convenient titration and isolation techniques have not been available for the study of these organisms. In recent reports (3, 5), however, we demonstrated the use of a sensitive plaque test for measuring concentrations of typhus and spotted fever rickettsiae. Studies were then initiated to determine whether this assay system is appropr...

Plaque assay and cloning of scrub typhus rickettsiae in irradiated L-929 cells.

It was demonstrated that gamma-irradiated L-929 cells support plaque formation by three strains of Rickettsia tsutsugamushi and representative species of the spotted fever and typhus group rickettsiae. Sensitivity of the plaque assay for detection of viable scrub typhus rickettsiae was similar to that achieved with intraperitoneal inoculation of random-bred mice. The concentration of irradiated...

Plaque assay for Rickettsia rickettsii.

A plaque technique for the assay of Rickettsia rickettsii is described. The method employs primary chick or green monkey kidney monolayer cell cultures with either an agarose or special Noble agar overlay. Plaques were counted in 6 days and resultant titers correlated well with ld(50) end points obtained by a standard assay in embryonated eggs. Identification of the plaque-forming organisms was...