Molecular heterogeneity of plpE gene in Indian isolates of Pasteurella multocida and expression of recombinant PlpE in vaccine strain of P. multocida serotype B: 2

ABSTRACT

Outer membrane proteins of Pasteurella (P.) multocida have been known to be protective immunogens. Pasteurella lipoprotein E (PlpE) has been reported to be an important cross reactive outer membrane protein in P. multocida. The gene encoding the PlpE of P. multocida serotypes A 3, B 2 and D 1 was amplified from the genomic DNA. The amplified products were cloned and the nucleotide sequence was determined. Sequence analysis of the recombinant clones revealed a single open reading frame of 1,011 bp, 1,008 bp and 1,017 bp encoding a protein with a calculated molecular mass of 37.829 kDa, 37.389 kDa and 37.965 kDa for serotypes A 3, B 2 and D 1 respectively. The comparison of the plpE sequence in different capsular types revealed a high degree (>90%) of homology. Furthermore, the plpE gene of Haemorhhagic septicaemia causing serotype (B 2) was expressed in E. coli and recombinant PlpE was strongly immunostained by antiserum against whole cell antigen, indicating that the protein is expressed in vivo.