Molecular characterization and immunogentic properties of a group 3 membrane protein isolated from B. abortus infection

Abstract

This study was conducted to evaluate the immunogenicity and protective efficacy of B. abortus protein antigen. A gene that encode 0.85 kbp was isolated from B. abortus genome λgt11 expression library by probing with a Polled Human Abs (PHAbs) infected with B. abortus or B. melitensis. Sequence analysis of the cloned gene revealed the presence of an Open Reading Frame (ORF) of 259 amino acids encoding for a protein with calculated molecular weight of 23 kDa (Bp23). The predicted amino acid sequences of this gene shows 83% similarity with B. abortus outer membrane 26 kDa protein (Omp26) previously sequenced. The recombinant B. abortus protein was identified by human sera infected with either B. abortus or B. melitensis, but not healthy persons as shown by Western blotting. Therefore, the availability of this recombinant protein and the identification of the antigenic determinant recognized by human Ab will allow the evaluation of its potential protective activity for the development of subcellular vaccines against brucellosis. Moreover, the use of this recombinant protein in Western blotting allowed differentiation between vaccinated from naturally infected camels. Hyperimmune rabbit serum against Bp23 recombinant protein could detect naturally infected animals with different specificities, whereas represented in camels (100%), cows (54%) and sheep (33%), but not detected at all in brucellosis free camels. These data indicated that the new isolated Bp23 recombinant protein might be of value as a vaccine candidate for treatment of human brucellosis and as an antigen for serological diagnosis of brucellosis in different animals as well. © 2007 Asian Network for Scientific Information.