EGHO-4 Viruses: Improved Methods and Strain Selection for Identification and Serodiagnosis

Abstract

Studies are reported that have shown that the tube neutralization identification test for ECHO-4 viruses is unreliable and that the most reliable identification method at present is the complement fixation test. It has been demonstrated that immunization of guinea pigs and monkeys with ECHO-4 virus grown in Detroit-504 human fibroblast- like cells produces an antiserum free of antibody which will react with Rhesus monkey kidney cell culture antigens, thereby eliminating cell culture cross-reactions and yielding a highly specific diagnostic reaction even with virus antigens of low antigenicity. The ability of ECHO-4 antibodies to readily neutralize DuToit strain as reported by Barron and Karzon has been confirmed and our strain 5705 was found to have similar properties. As suggested by these investigators, DuToit-like strains should probably be employed to detect neutralizing antibodies in human patients'' sera.