Efficacy of inactivated vaccine containing cyto-hemagglutinin against epidemic hemorrhagic fever in rabbits.

Using the Z-10 strain of epidemic hemorrhagic fever virus (EHFV) as seed, and the primary cell of Meriones unguiculatus kidney tissue as incubation cell, a propiolactone inactivated epidemic hemorrhagic fever (EHF) vaccine was prepared, according to a similar procedure required for the production of biological products such as the Japanese B encephalitis vaccine. Besides the EHFV antigen detected by ELISA or reversed passive hemagglutination test (RPHA) as were used for the formalin inactivated vaccine, higher titres (1:128-1:1024) of EHFV hemagglutinin antigen was also detected in this EHFV vaccine. Immunization with twice intramuscular injection of this vaccine produced high titred (1:20-1:160) neutralizing antibody and low titred (1:10-1:20) hemagglutination antibody, in addition to the immunofluorescence (IF) and reversed passive hemagglutination inhibition (RPHI) antibodies. These results indicated an apparent difference in the immunogenicity between the beta-propiolactone and formalin inactivated EHF vaccines. With the approval of the Ministry of Health, human test is now underway in this laboratory.