Production of recombinant fusion protein rPstS1-HspX and application in serodiagnosis of tuberculosis

Abstract

Objective To express and purify rPstS1-HspX (rPH)fusion protein of Mycobacterium tuberculosis H37Rv and evaluate its application in serodiagnosis of tuberculosis.Methods The expression of rPH fusion protein was induced with isopropyl-βthiogalactopyranoside (IPTG).Then the fusion protein was purified by nickel afiinity chromatography,and the immunoreactivity of purified rPH was evaluated by Western blot.Finally,the purified fusion protein was used as antigens to screen the sera from the patients with pulmonary TB ( n =94),as well as other pulmonary disease ( n =52),and clinically healthy controls ( n =48) by ELISA.Results The expressed 51 000 rPH fusion protein mainly existed in soluble form.After nickel affnity chromatography,the purity of rPH reached 92％ (0.62 ng/mL).Specific immunoreactivity of purified rPH to positive serum from tuberculosis patients was confirmed by Western blot.The results of ELISA showed that the sensitivity and specificity of rPH were 77.6％ (73/94) and 92.0％ (92/100),respectively.Conclusions The rPH fusion protein is successfully expressed and purified.Ptuified rPH fusion protein,which can provide a satisfactory sensitivity and specificity in serodiagnosis of tuberculosis,may become effective antigen in ELISA.Conclusions The rPH fusion protein is successfully expressed and purified.Ptuified rPH fusion protein,which can provide a satisfactory sensitivity and specificity in serodiagnosis of tuberculosis,may become effective antigen in ELISA. Key words: Mycobacterium tuberculosis; rPstS1-HspX fusion protein; Serodiagnosis