Rational vaccine design requires understanding details of protective immunity against each virus. Yasuko Mori and associates from Japan have now identified CD4+ and H-2Kd restricted CD8+ T-cell epitopes essential for HHV-6B viral entry, opening new possibilities for vaccines and immunotherapy.
Yasuko Mori and colleagues were successful in humanizing two neutralizing monoclonal antibodies to HHV-6B. The chimeric antibodies performed well enough to show promise for therapeutic use.
Although foscarnet is widely used for HHV-6 encephalitis, it has never been specifically approved for HHV-6. Japan’s Ministry of Health, Labor and Welfare was the first to approve foscarnet (Foscavir) for the treatment of HHV-6 encephalitis.
A Japanese trial of foscarnet prophylaxis in cord blood transplant patients was successful in reducing severity and mortality as well as suppressing high viral loads, but it failed to prevent encephalitis. The authors note that the blood brain barrier must be inflamed to allow effective penetration of the drug into the central nervous system and speculate that the prophylaxis may have protected the meninges.
Investigators at Johns Hopkins have determined that emetine, an older drug used to treat dysentery as well as to induce vomiting, is also effective against cytomegalovirus (CMV/HHV-5). Not only was emetine effective at an extremely low dose, it demonstrated a synergistic effect when combined with ganciclovir in a mouse model of CMV infection and it worked at a much earlier stage of viral replication than the drugs currently in use.
A group from the University Medical Center in the Netherlands has shown that new gene editing technology can be used to impair viral replication and clear latent herpesvirus infections. The group used a CRISPR-Cas system to target viral genetic elements that completely eliminated CMV and HSV1 replication. They were also able to clear latent EBV from transformed human tumor cells.
Chimerix “SUPPRESS” trial to be largest study ever conducted for treatment of HHV-6 infection
A set of novel compounds synthesized by Microbiotix, Inc. have shown increased activity against a broad spectrum of human herpesviruses, including HHV-6.
Data from a recent report may increasingly argue in favor of using the antiviral known as CMX001 for treatment of HHV-6 infection.