Protective role of antibodies induced by Brucella melitensis B115 against B. melitensis and Brucella abortus infections in mice

► The rough strain B. melitensis B115 induces antibodies to antigens other than O-PS. ► Antibodies induced by B115 protected against Brucella infections in mice. ► Antibodies induced by B115 could act as opsonins as well as antibodies to O-PS.