T-h-2 immunity and CD3+ CD45RBlow-activated T cells in mice immunized with recombinant bacillus Calmette-Guérin expressing HIV-1 principal neutralizing determinant epitope

Abstract

The genetic engineering of Mycobacterium bovis-bacillus Calmette-Guérin to express foreign epitopes is an attractive strategy in the field of epitope vaccines. We constructed an 'epitope-trap vector' with Mycobacterium tuberculosis chaperonin-10 as a carrier antigen and used it to express the HIV-1 principal neutralizing determinant epitope. We also identified a new chaperonin-10 promoter that was hyperexpressive compared with the heat shock protein-65 promoter. Splenocytes from recombinant bacillus Calmette-Guérin-immunized mice showed enhanced lymphocyte proliferation and interleukin-4 (but not interferon-γ) secretion. The recombinant bacillus Calmette-Guérin-immunized group also exhibited mild delayed-type hypersensitivity reaction and a high frequency of CD3+CD45RBlow-activated T cells, together with high titer of antiprincipal neutralizing determinant immunoglobulin G antibodies. Thus, this epitope delivery system induced strong epitope-specific T-h-2 polarization. © 2006 Federation of European Microbiological Societies Published by Blackwell Publishing Ltd. All rights reserved.