Protective vaccine efficacy of the complete form of PPE39 protein from Mycobacterium tuberculosis Beijing/K strain in mice

The aim of this study was to evaluate the protective efficacy of MTBK_24820, a complete form of PPE39 protein derived from a predominant Beijing/K strain of Mycobacterium tuberculosis in South Korea. Mice were immunized with MTKB_24820, M. bovis Bacilli Calmette-Guerin, or adjuvant prior to a high-dosed Beijing/K strain aerosol infection. After 4 and 9 weeks, bacterial loads were determined and histopathologic and immunologic features in the lungs and spleens of the M. tb -infected mice were analyzed. Putative immunogenic T-cell epitopes were examined using synthetic overlapping peptides. Successful immunization of MTBK_24820 in mice was confirmed by increased IgG responses (P 10 reduction in lungs in colony forming units and fewer lung inflammation lesions were observed in MTBK_24820-immunized mice compared with control mice. Moreover, MTBK_24820 immunization elicited significantly higher numbers of CD4 + T cells producing protective cytokines, such as IFN-γ and IL-17, in lungs and spleens (P + multifunctional T cells producing IFN-γ, TNF-α, and/or IL-17 (P in vivo may be informative for vaccine development, particularly in regions where the M. tb Beijing/K-strain is frequently isolated from TB patients.