Immunolocalization of VirB11 protein in the Anaplasma marginale outer membrane and its reaction with bovine immune sera

Abstract

Type IV secretion system is composed by a group of proteins associated with substrate transfer between bacteria and eukaryotic organisms. VirB11 is a protein of this system and, in A. marginale it induces partial protection in cattle immunized with external membrane fragments of the rickettsia. The objectives of this study were: to determine the conservation rate of VirB11 among different Mexican isolates and to corroborate its cellular localization on the outer membrane of A. marginale. Nucleotide and amino acid sequence alignment of virB11 from nine Mexican isolates showed 100 % identity. Bovine sera from both naturally and experimentally infected cattle reacted against a multiple antigenic peptide (MAP-VirB11) designed based on a B-type epitope present in VirB11. In addition, MAP-VirB11-rabbit immune sera reacted with native VirB11 by ELISA and western blot in rickettsial extracts and on the surface of bovine infected erythrocytes by indirect immunofluorescence and the localization of VirB11 protein was determined on the outer surface of A. marginale initial bodies.

Keywords

• anaplasma marginale
• type 4 secretion system
• multiple antigenic peptide
• map
• virb11