| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1999: ¥1,800,000 (Direct Cost: ¥1,800,000)
|
|---|
| Research Abstract |
Equine herpesvirus-1 (EHV-1) has long been causally implicated in the occurrence of abortion, respiratory disease, neonatal deaths and neurological disorders in horses. Outbreaks of abortion due to EHV-1 have been observed almost every year and causes severe economic loss in the horse breeding industry. In attempts to prevent an abortion caused by EHV-1 infection, inactivated vaccine was applied to pregnant mares but with little efficacy. It was suggested that an importance for the role of cellular immunity in defense against EHV-1 infection, particularly abortion. We obtained an attenuated BK320 strain after serial 320 passages of virulent EHV-1 in bovine kidney cell cultures as a live modified vaccine strain. However, in horses inoculated experimentally with BK320, protection against challenge with virulent EHV-l was not elicited. We planed to construct recombinant EHV-1 to elicit cellular immunity effectively by adding DNA adjuvant (immunostimulatory oligonucleotide) and immune regulatory cytokines such as interleukin (IL) 2, IL-12 and interferon-gamma on genetically attenuated EHV-1 genome. First, we obtained a quadruple glycoprotein (gD,gE,gI and gp 2)-deleted virus mutant that could produce infectious virions only on cells expressing the four glycoproteins. Therefore, this mutant could not produce infectious virus under natural conditions and might not cause a latent infection in horse. Now, we have been screening the recombinant viruses carrying the DNA adjuvant or equine IL-2, IL-12 and interferon-gamma genes.
|
