Cloning, Expression and Immunological Characterization of P30 protein of Mycoplasma pneumoniae

Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India; Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India; International Center for Genetic Engineering and Biotechnology, New Delhi, India

^* To whom correspondence should be addressed. Email: ramach{at}aiims.ac.in. pawanm{at}icgeb.res.in.

	Abstract

Mycoplasma pneumoniae, a self-replicating cell wall deficient prokaryote has a differentiated terminal organelle that is essential for cytadherence and gliding motility. P30, an important protein associated with the terminal organelle is required for cytadherence and virulence of M. pneumoniae. P30 is a transmembrane protein with an intracytoplasmic N-terminal and exposed C- terminal. In the present study, we amplified and sequenced the full length p30 gene of Mycoplasma pneumoniae directly from eighteen Indian asthmatic patients. Sequence diversity was observed in p30 gene from sixteen clinical samples when compared with M-129 strain. We also successfully expressed a fragment of p30 gene (P30-B) that includes the complete C-terminal proline-rich amino acid sequences in different E. coli expression system. The MBP-P30B fusion protein was recognized by M. pneumoniae infected patient sera in immunoblot and the protein was immunogenic in mice. We further analyzed the reactivity of MBP-P30B fusion protein with patient sera in an ELISA and compared it with the commercial kit (Serion ELISA Classic kit). The sensitivity and specificity of in-house ELISA was 78.57% and 89.47% respectively. This study suggests that P30 protein can be used as an antigen for immunodiagnosis for M. pneumoniae infection along with other adhesin proteins.