Cited by 1.3k
Tel Aviv University
Publishes on Virology and Viral Diseases, Viral Infections and Immunology Research, Hepatitis C virus research. 5 papers and 1.4k citations.
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When tested on RK(13) cell cultures, strains of rubella virus could be differentiated by their ability to form small or large plaques. Large plaques were produced by the HPV-77 and Cendehill strains, and also by a laboratory stock strain (West Point), after only 14 passages in RK(13) culture. Five wild-type rubella viruses, isolated and passaged only a few times in African green monkey kidney tissue culture, grew well in RK(13) cell culture, but they were sensitive to agar inhibitors and, therefore, formed small plaques. On the other hand, RA27/3, an attenuated strain grown in WI-38 human fibroblast cells, developed low titers in RK(13) cells and also produced small plaques. We concluded that the morphological differences between small-plaque and large-plaque viruses depended on their sensitivity to agar inhibitors and on the pH of the medium during plaque formation.
A case of reinfection with the wild rubella virus in the 8th gestational week is reported. The patient had preexisting hemagglutination inhibition antibodies of low titer following immunization with rubella vaccine. Reinfection was accompanied by clinical symptoms and the presence of rubella-specific immunoglobulin M (IgM) of high titer. Following termination of pregnancy no rubella virus could be isolated from the fetal tissues and the fetal blood contained no specific IgM antibodies. These results should encourage the use of cordocentesis before decision on interruption of pregnancy.
Human embryonic intestine in organ culture was found to support the multiplication of polioviruses for periods up to 4 months. The character of attenuated Type 3 strains following cultivation in this system was found to change from rct/40− to rct/40+, while Type 1 attenuated viruses remained rct/40− even after prolonged multiplication (up to 73 days in the same system). The growth rate of virulent H-24 strain was much higher than that of attenuated WM-3 virus in the intestinal explants. Similarly, an rct/40+ guanidine-re-sistant mutant of WM-3 virus, both singly and when mixed with the original rct/40− guanidine-sensitive strain, was more infectious and multiplied to higher riters in the explants. These results appear to be similar to the observed behavior of Type 3 virus strains in the human intestinal tract, and offer an explanation for the tendency to lose markers associated with attenuation.