Induction of CD4(+) T cell-dependent CD8(+) type 1 responses in humans by a malaria DNA vaccine
R Wang, J Epstein, F M Baraceros, E J Gorak, Y Charoenvit, D J Carucci, R C Hedstrom, N Rahardjo, T Gay, P Hobart, R Stout, T R Jones, T L Richie, S E Parker, D L Doolan, J Norman, S L Hoffman, R Wang, J Epstein, F M Baraceros, E J Gorak, Y Charoenvit, D J Carucci, R C Hedstrom, N Rahardjo, T Gay, P Hobart, R Stout, T R Jones, T L Richie, S E Parker, D L Doolan, J Norman, S L Hoffman
Abstract
We assessed immunogenicity of a malaria DNA vaccine administered by needle i.m. or needleless jet injection [i.m. or i.m./intradermally (i.d.)] in 14 volunteers. Antigen-specific IFN-gamma responses were detected by enzyme-linked immunospot (ELISPOT) assays in all subjects to multiple 9- to 23-aa peptides containing class I and/or class II restricted epitopes, and were dependent on both CD8(+) and CD4(+) T cells. Overall, frequency of response was significantly greater after i.m. jet injection. CD8(+)-dependent cytotoxic T lymphocytes (CTL) were detected in 8/14 volunteers. Demonstration in humans of elicitation of the class I restricted IFN-gamma responses we believe necessary for protection against the liver stage of malaria parasites brings us closer to an effective malaria vaccine.
Figures
Source: PubMed