Isolation of three Brucella abortus cell-wall antigens protective in murine experimental brucellosis

Abstract

The insoluble fraction, SDS-I, obtained by boiling cell-walls of Brucella abortus in sodium dodecyl sulfate (SDS) was hydrolyzed by lysozyme. Three major bands of apparent molecular weight 37000 (I), 25000 (II), 15000 (III) were isolated by gel slicing after polyacrylamide gel electrophoresis in the presence of SDS. The three bands were injected subcutaneously to mice using Freund incomplete adjuvant and immunity was tested one month later by intraperitoneal administration of a virulent strain of B. abortus. Fifteen days after challenge, numbers of viable brucella within the spleens were determined. The isolated bands, I, II and III were able to protect mice at a level corresponding to the killed whole-cells Brucella melitensis H38 reference vaccine.