"Original Sin" Immune Response Defeated
Flu vaccines have long been thwarted by what scientists call "original antigenic sin." According to a press release from Emory University, after encountering one viral strain and then a new one that is related to the first, the immune system may respond by making antibodies only against the first strain. The result in a less effective defense. Now, however, researchers at the Emory Vaccine Center have demonstrated that the "sin" reaction can be overcome either with a vaccine additive called an adjuvant, or by repeated immunization with the second viral strain.
The results of the study, led by Jin Hyang Kim of the Centers for Disease Control and Prevention and Joshy Jacob, associate professor of microbiology and immunology at Emory University School of Medicine, were published in the Proceedings of the National Academy of Sciences.
The authors maintain that their findings are especially important for the elderly and others with weaker immune systems. "Original antigenic sin is really a reflection of the agility of the influenza virus," he says. "OAS becomes a factor when the new circulating strain is a 'drifted' version of what came before. The old antibodies can't neutralize the new virus, and that helps the new virus survive."
The researchers say the best approach for older people with prior influenza virus exposure or vaccinations is the addition of an adjuvant to the vaccine.