COMPOSITION AND METHOD FOR OBTAINING SPECIFIC IMMUNISATION AGAINST ONE OR MORE ANTIGENS USING DIFFERENT RECOMBINANT VECTORS

摘要

A large number of recombinant of viral and bacterial systems has been engineered as vectors to express foreign genes for vaccination and/or gene therapy. A common problem is the immune response to the vector itself. The presence of anti-vector immune responses may preclude sufficient priming or delivery if pre-existing immune responses are present, or impair optimal "boosting" upon subsequent immunisation or delivery. The invention provides means and methods for vaccinating an animal or a human to obtain therein an immune response against at least one antigen, comprising different vaccine compositions for sequential administration to said animal or said human, each containing at least said antigen or a precursor thereof, wherein said vaccine compositions differ from each other by the presence therein of a different vector.