Adjuvant effect of anti-idiotypic antibodies to Yersinia pestis lipopolysaccharide

Rabbit anti-idiotypic antibodies (anti-Id-ab) against Yersinia pestis lipop olysaccharide (I;PS) were obtained with monoclonal immunoglobulins. Their c omplementary character to the original antigen was confirmed by immunohisto chemical analysis and ELISA and gel precipitation tests. The anti-Id-ab wer e shown to possess all essential properties of Ab2 beta subtype. Both in-vi tro and in-vivo experiments demonstrated a pronounced adjuvant activity of anti-Id-ab without the toxic effect characteristic of I: pestis LPS. Combin ed immunisation with anti-Id-ab plus the FI capsular antigen led to a signi ficant increase in the protective immune response against experimental acut e challenge with virulent Y. pestis.