Herpes Vaccine Looks Promising, Researchers Say
May 4, 2000 -- Preliminary tests of a vaccine to fight the herpes simplex
virus are showing that the vaccine can prevent illness and death in mice with
herpes, according to scientists at the recent Conference on Vaccine Research in
Researcher Ken S. Rosenthal, PhD, tells WebMD that the information being
gleaned about viral infection and protection may eventually lead to effective
prevention and treatment for diseases from malaria to cancer.
The CDC estimates that 25% of the U.S. adult population is already infected
with genital herpes, and 600,000 new cases will be diagnosed this year. While
herpes is not fatal in adult humans, the painful, incurable disease disrupts
lives, affecting the social and sexual behavior of people who are infected.
Herpes can be passed unwittingly to sexual partners even when sores are not
present, and can cause blindness if the eyes are infected. Over half of the
infants who contract herpes from their mothers before delivery or during
childbirth will die or develop serious complications.
The vaccine, being developed with CEL-SCI Corp, "is working and it looks
promising," says Rosenthal, a professor of microbiology and immunology at
Northeastern Ohio Universities College of Medicine. He tells WebMD that some
hard information on the research should be available within the next few
"We've demonstrated that we can take different epitopes, which are
molecular structures recognized by the immune system, and make them into
vaccines that will immunize animals," Rosenthal tells WebMD. What's most
exciting, he says, is that the researchers have discovered a way to direct the
type of immune response that is caused. This is important because some
diseases are controlled better by T-cells while others can be fought off more
effectively by antibodies, he says.
While both immune responses are important, they serve different purposes.
T-cells work locally, at the site of infection, to attack an invading virus or
bacteria. Antibodies, on the other hand, circulate in the blood, catching
stragglers and preventing them from establishing a foothold. After an initial
infection is controlled, says Rosenthal, what you want is a "memory
response" in the body, to recognize and fight off the same invader if it's
ever seen again. This "memory response" is what we call immunity.
"We've been able to analyze the immune response that's generated in the
mice, and ... we've found that it's the T-cell response, rather than the
antibody response, that is essential for protection" against herpes,
Rosenthal tells WebMD.
In herpes infection, the preliminary, T-cell response is inadequate, and
there is no memory response.
"The herpes virus can escape antibody control," Rosenthal says. It
moves directly from cell to cell without being recognized and eradicated.
That's why having circulating herpes antibodies does not mean you've
successfully fought off infection and are now immune, but rather that you've
got the disease and are subject to repeated outbreaks. And that's why eliciting
the T-cell response is key to the success of a herpes vaccine, Rosenthal says.
According to Rosenthal, future studies will take a three-pronged approach:
"We are looking at the vaccine for prevention, for treatment -- giving it
to someone with herpes to reduce the frequency and severity of occurrences --
and as an added component in another vaccine, to boost the T-cell
Potentially, he says, this technology could be applied to any disease where
the epitopes are known. He tells WebMD that early testing has already begun of
vaccine systems for protection against malaria, HIV, heart disease, and