Abstract
Some biological, physicochemical and antigenic properties of the MI-110 strain of Getah virus (GV) were examined at the tenth passage level in Vero cell cultures. The virus produced CPE in a wide variety of cells, including eleven kinds of primary equine fetal cells. Especially, it multiplied to the highest titer (107.5 TCID50/0.2 ml) in primary equine fetal lung, BHK-2l, HmLu and Vero cell cultures. The MI-110 strain was sensitive to a high concentration of trypsin, an acid pH value of less than 5.0, an alkaline pH value of more than 10.0, and heating at more than 50°C, especially heating in IM MgCl2 at 50°C. Moreover, it was unstable at 20 or 37°C, but survived at l0°C for 3 months, at 4°C for 6 months, and at -20 or -80°C for more than 2 years. In the cross virus neutralization, hemagglutination inhibition and complement fixation (CF) tests, this strain was proved to be quite closely related to the AMM 2021, Haruna and Sakai strains of GV, whereas it was a little more closely related to Sagiyama virus. Besides, it had a rather weak antigenic relationship with Ross River, but not with Chikungunya virus, except in the CF test. From these results, it was concluded that four strains of GV, or the AMM 2021, Haruna, MI-110 and Sakai strains, belonged antigenically to the same virus, and that Sagiyama virus might probably be classified in a subtype of GV.
