1 research outputs found
Identification of an N-terminal 27 kDa fragment of Mycoplasma pneumoniae P116 protein as specific immunogen in M. pneumoniae infections
<p>Abstract</p> <p>Background</p> <p><it>Mycoplasma pneumoniae </it>is an important cause of respiratory tract infection and is increasingly being associated with other diseases such as asthma and extra-pulmonary complications. Considerable cross-reactivity is known to exist between the whole cell antigens used in the commercial serological testing assays. Identification of specific antigens is important to eliminate the risk of cross-reactions among different related organisms. Adherence of <it>M. pneumoniae </it>to human epithelial cells is mediated through a well defined apical organelle to which a number of proteins such as P1, P30, P116 and HMW1-3 have been localized, and are being investigated for adhesion, gliding and immunodiagnostic purposes.</p> <p>Methods</p> <p>A 609 bp fragment P116<sub>(N-27), </sub>corresponding to the N-terminal region of <it>M. pneumoniae </it>P116 gene was cloned and expressed. A C-terminal fragment P1<sub>(C-40), </sub>of P1 protein of <it>M. pneumoniae </it>was also expressed. Three IgM ELISA assays based on P116<sub>(N-27), </sub>P1<sub>(C-40) </sub>and (P116 <sub>(N-27) </sub>+ P1<sub>(C-40)</sub>) proteins were optimized and a detailed analysis comparing the reactivity of these proteins with a commercial kit was carried out. Comparative statistical analysis of these assays was performed with the SPSS version 15.0.</p> <p>Results</p> <p>The expressed P116<sub>(N-27) </sub>protein was well recognized by the patient sera and was immunogenic in rabbit. P1<sub>(C-40) </sub>of <it>M. pneumoniae </it>was also immunogenic in rabbit. In comparison to the reference kit, which is reported to be 100% sensitive and 75% specific, ELISA assay based on purified P116<sub>(N-27), </sub>P1<sub>(C-40) </sub>and (P116<sub>(N-27) </sub>+ P1<sub>(C-40)</sub>) proteins showed 90.3%, 87.1% and 96.8% sensitivity and 87.0%, 87.1% and 90.3% specificity respectively. The p value for all the three assays was found to be < 0.001, and there was a good correlation and association between them.</p> <p>Conclusion</p> <p>This study shows that an N-terminal fragment of P116 protein holds a promise for serodiagnosis of <it>M. pneumoniae </it>infection. The IgM ELISA assays based on the recombinant proteins seem to be suitable for the use in serodiagnosis of acute <it>M. pneumoniae </it>infections. The use of short recombinant fragments of P116 and P1 proteins as specific antigens may eliminate the risk of cross-reactions and help to develop a specific and sensitive immunodiagnostic assay for <it>M. pneumoniae </it>detection.</p