Expression and immunological characterization of the major epitope of P1 adhesin protein of Mycoplasma pneumoniae and its clinical application research

Objective To study the application of P1 adhesin protein epitopes in diagnosis of Mycoplasma pneumoniae(Mp) infected patient. Methods The major epitope(P1-534) of P1 adhesin protein were predicted by ProPred and ANTIGENIC according to its primary structure. The high value fragment was cloned into a constructed recombinant vector. The gene was induced to express fusion protein in E. coli host strain BL21(DE3) and the fusion protein was identified by Western blot. BALB/c mice were immunized with purified protein to test its immunogenicity. Then the purified protein was used as antigen to test the serum of Mp infected patient by ELISA, and compared with the Mp whole cell antigen. Results The P1-534 protein was successfully expressed and purified. ELISA data showed that P1-534 protein could elicit high levels of IgG in immunized mice, the sensitivity and specificity of P1-534 were determined to be 85.00% and 97.67%, while the Mp whole cell antigen were 72.50% and 74.42%. Conclusion The results conformed that the recombinant epitope has certain immunogenicity,and its sensitivity and specificity are better than Mp whole cell antigen. P1-534 protein can be used as an antigen for immunodiagnosis of Mp infection. Key words: Mycoplasma pneumoniae;  Adhesin protein;  Antigen;  Expression;  Immunogenicity