Nasal vaccination using live bacterial vectors

Live recombinant bacteria represent an attractive means to induce both muco sal and systemic immune responses against heterologous antigens. Several mo dels have now been developed and shown to be highly efficient following int ranasal immunization. In this review, we describe the two main classes of l ive recombinant bacteria: generally recognized as safe bacteria and attenua ted strains derived from pathogenic bacteria. Among the latter, we have dif ferentiated the bacteria, which do not usually colonize the respiratory tra ct from those that are especially adapted to respiratory tissues. The strat egies of expression of the heterologous antigens, the invasiveness and the immunogenicity of the recombinant bacteria are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.