Protection against Brucella melitensis or Brucella abortus in mice with immunoglobulin G (IgG), IgA, and IgM monoclonal antibodies specific for a common epitope shared by the Brucella A and M smooth lipopolysaccharides.

Mice passively immunized prior to a challenge infection with immunoglobulin G (IgG) and IgM monoclonal antibodies (MAbs) specific for a common epitope of both A- and M-dominant strains had viable Brucella abortus 544 or Brucella melitensis H38 counts in the spleen reduced to the same extent as did mice passively immunized with MAbs specific for either the A or the M epitope. The IgA MAb was not effective.