Vaccine with CTL and Th epitopes more effective against HPV-induced cervical tumors.(Brief Article)

2002 SEP 25 - (NewsRx.com & NewsRx.net) -- by Maria G. Essig, MS, ELS, senior medical writer - A vaccine containing cytolytic and helper T-lymphocyte epitopes of the human papillomavirus (HPV) elicited a stronger immune response than did a vaccine containing only the cytolytic T lymphocyte epitope, according to an international research team.

"Peptide-based vaccines aimed at the induction of effective T-cell responses against established cancers have so far only met with limited clinical success and clearly need to be improved," said Sander Zwaveling and colleagues at Leiden University in the Netherlands, Corixa Corp. (U.S.), and Coley Pharmaceutical (Germany).

In an HPV-induced cervical cancer model, the investigators compared immune responses with vaccines containing either HPV cytolytic T lymphocyte (CTL) plus helper T lymphocyte (Th) epitopes (long peptide vaccine) or the CTL epitope alone. The epitopes were derived from the E7 peptide of the HPV16 strain.

The E7-specific CD8+ response was significantly greater for the vaccine containing the CTL plus Th epitopes than for the vaccine with only the CTL epitope. The authors presented data to explain the greater response of the CTL plus Th vaccine (Established human papillomavirus type 16-expressing tumors are effectively eradicated following vaccination with long peptides. Journal of Immunology, 2002;169(1):350-358).

The immune response involved vaccine stimulation of E7-specific CD4+ helper T lymphocytes, which, by interacting with antigen-presenting cells, control the level of the CD8+ T cell response.

When the vaccine included a component that activated dendritic ...