Immune responses induced by BCG recombinant for human papillomavirus L1 and E7 proteins

Recombinant bacille Calmette-Guerin (BCG) based vaccine delivery systems co uld potentially share the safety and effectiveness of BCG. We therefore pre pared recombinant BCG vaccines which expressed the L1 late protein of the h uman papillomavirus (HPV) 6b or the E7 early protein of the HPV 16. The two recombinants were evaluated as immunogens in C57BL/6J and BALB/c mice, and compared with a conventional protein/adjuvant system using E7 or L1 mixed with Quil-A adjuvant. rBCG6bL1 and rBCG16E7 primed specific immune response s, represented by DTH, T-proliferation and antibody, and rBCG16E7 induced c ytotoxic immune response to E7 protein. The magnitude of the observed respo nses were less than those elicited by protein/adjuvant vaccine. As recombin ant BCG vaccines expressing HPV6bL1 or HPV16E7 persist at low levels in the immunised host, they may be beneficial to prime or retain memory responses to antigens, but are unlikely to be useful as a single component vaccine s trategy. (C) 2000 Elsevier science Ltd. All rights reserved.