Meeting report: 30th International Conference on Antiviral Research, in Atlanta, GA, USA

Vere Hodge, R Anthony

In conclusion, transmitted polymorphisms can affect HIV disease progression. With low vRC and original non-adapted epitopes, the disease will progress more slowly. High vRC and adapted epitopes will aid rapid disease progression. Alternatively, these functions can oppose each other, the balance defining viral virulence. Although there are no approved antiviral therapies for flaviviruses, there are some vaccines, for example, yellow fever virus vaccine. This suggests that a vaccine for Zika virus may be possible -certainly, the medical need is high. Generally, inactivated vaccines and subunit vaccines have a better safety profile than live attenuated vaccines. However, the later may give lifetime immunity after a single dose, a feature that Pei-Yong considered critical for a successful Zika vaccine. He has considered two possible approaches to produce an attenuated vaccine with a good safety profile; to knockout a key viral enzyme or to delete sections of the three prime untranslated region (3 0 UTR). His target enzyme was methyltransferase, which enables the Zika virus to acquire a cap to protect the viral RNA. The active site was inactivated by changing two amino acids. In the 3 0 UTR approach, he compared vaccines with 10-, 20and two different 30-nucleotide deletions. Rather unexpectedly, the 10-nucleotide deletion (10-del ZIKV) seemed to be more attenuated than both a 20-or 30nucleotide deletion vaccines. This may be due to the 10del ZIKV being more susceptible to IFN than the other deletion vaccines -the reason for the differing IFN responses is not known. The 10-del ZIKA vaccine was the focus of the remainder of his ICAR presentation. The initial evaluation was done in a mouse model using type 1 IFN receptor-deficient A129 mice. To study the protective effect provided by vaccination in pregnant mice, C57BL/6 mice were used. Studies on male mice used A129 mice. Then safety and efficacy were confirmed in rhesus macaques.