All smooth strains of bear two lipopolysaccharide (LPS) antigens in a ratio that defines the classification of strains in serovars, A (A≥M), M (M>A) and A.M (A = M). Anti-LPS-A monoclonal antibodies (MAb-A) were previously shown to convey protection to mice against (A) strain 544, as shown by lower spleen counts than in controls at days 7 and 21 after challenge. Anti-LPS-M monoclonal antibodies (MAb-M) were obtained and tested for M-specificity with LPS from reference strains by ELISA, by agglutination of LPS-coated latex particles, and by inhibition of this agglutination. Antigens A and M of three strains were quantified by a homologous LPS-latex and MAb agglutination inhibition assay. Protection conferred by MAb-A and MAb-M against three strains, 544 (A), 292 (M) and H38 (M), was tested at equivalent challenge and MAb doses: intravenous challenge was adjusted to give similar infection at day 7;MAb doses were adjusted to the same specific ELISA titre. Under these conditions, MAb-A and MAb-M conferred both early and late protection, as shown at days 7 and 21, against the strains that bore the homologous major antigen, , strain 544 on one hand and strains H38 and 292 on the other. In contrast, MAb directed against the minor antigen of the challenge strain conferred significant protection at day 7 only with strains 544 and H38 and no or inconsistent protection against strain 292, which expressed the lowest amount of minor antigen. Thus, early and late antibody-mediated immune mechanisms depend on amounts of surface LPS antigens accessible to specific antibodies. Therefore, to protect against the various strains of , an LPS-based vaccine should induce high litres of specific antibodies against both A and M antigens.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error