Oral DNA Vaccines Depend On Macrophages For Hepatitis B Immune Response.(Brief Article)

2001 DEC 12 - (NewsRx.com & NewsRx.net) -- by Sonia Nichols, senior medical writer - Oral DNA vaccines against hepatitis B virus (HBV) depend on professional antigen-presenting cells in order to produce an immune response, investigators have learned.

However, these same vaccines evoke a different immune response when administered intramuscularly, signaling routes of administration are a significant component of effective protection when HBV DNA vaccines are used.

In an earlier study performed by B.J. Zheng and coworkers, University of Hong Kong, oral DNA vaccine comprising Salmonella typhi plasmid DNA containing hepatitis B surface antigen (HBsAg) induced a strong T cell response and a weak antibody response, "suggesting a significant involvement by professional antigen-presenting cells (APCs)," Zheng and colleagues noted.

A more recent study reported by Zheng and associates in the journal Vaccine indicated peritoneal macrophages infected with the oral DNA vaccine would generate strong lymphocyte proliferation, despite low antigen levels. Not only was there significant proliferation, but the new cells produced considerable amounts of interferon gamma and generated HBV-specific cytotoxicity against any cells unfortunate enough to be harboring the antigen.

When subsequently infused into murine models, the infected macrophages caused an immune response similar to the vigorous reaction seen before, producing a strong Th1 reaction, boosting ...