The Relation Between the Infectivity and the Hemagglutinin of Murine Encephalomyelitis Virus (GDVII)

Abstract

The usefulness of the hemagglutination test as a measure of viral concentration depends upon the constancy of the quantitative relationship between infectious virus and hemagglutinin. As additional viruses are found capable of inducing agglutination of red cells, it becomes necessary to determine whether the reaction is due wholly or in part to the virus itself, and to ascertain how inhibitory influences may affect the virus-hemagglutinin ratio. Observations reported to date on the GDVII strain of murine encephalomyelitis (1, 2) indicate that the agglutination of human red cells which occurs at 4 C, HA(4), with infected mouse-brain preparations is due to the virus per se. In the course of experiments already reported (3), however, it became clear that this problem needed further investigation. When infected mouse brain was treated with trypsin, agglutination of human cells occurred at 20 C, HA(20), although the untreated virus failed to cause hemagglutination at this temperature.