[Monoclonal antibodies against the lipopolysaccharide of Salmonella typhi 9,12,VI:d. Analysis of passive protection in a mouse model of typhoid fever].

The current work was undertaken in order to assess the role of the monoclonal antibodies (Mabs) to lipopolysaccharide (LPS) of Salmonella typhi in the induction of passive protection against the challenge with the bacteria in a mice model. BALB/c mice were immunized with the whole bacteria, mice with high anti-LPS antibody titers were killed, the spleens were removed and splenocytes were fused with the mouse plasmocytoma SP2/0. Two IgM monoclonal antibodies against porins were developed. Each one of these Mabs recognized the polysaccharide region of LPS. Passive immunization with supernatant fluid of mice with one of these monoclonal antibodies did not protect against challenged with 20 LD50 and 100 LD50 of Salmonella typhi. The results suggest that LPS is not valuable immunogen for the induction of a protective status against typhoid fever.