%0 Journal Article %A Chaitra, M. G. %A Shaila, M. S. %A Nayak, R. %T Evaluation of T-cell responses to peptides with MHC class I-binding motifs derived from PE_PGRS 33 protein of Mycobacterium tuberculosis %D 2007 %J Journal of Medical Microbiology, %V 56 %N 4 %P 466-474 %@ 1473-5644 %R https://doi.org/10.1099/jmm.0.46928-0 %K MHC, major histocompatibility complex %K IFN-γ, gamma interferon %K IL, interleukin %K BCG, bacille Calmette–Guérin %K ELISPOT, enzyme-linked immunosorbent spot assay %K LDH, lactate dehydrogenase %K PPD, protein-purified derivative %K TB, tuberculosis %I Microbiology Society, %X The PE and PPE proteins of Mycobacterium tuberculosis form a source of antigenic variation among different strains of M. tuberculosis. One of the PE_PGRS proteins, Rv1818c, plays a role in the pathogenesis of mycobacterial infection and specifically influences host-cell responses to tuberculosis infection. Although little is known about these two classes of protein, an immunoinformatics approach has indicated the possibility of their participation in eliciting a major histocompatibility complex (MHC) class I-mediated immune response against tuberculosis, as peptides derived from Rv1818c are predicted to bind to MHC class I molecules with high affinity. In the present work, a DNA vaccine was constructed encoding the full-length Rv1818c protein of M. tuberculosis and its immunogenicity was analysed in BALB/c mice. Immunization with Rv1818c DNA induced a strong CD8+ cytotoxic lymphocyte and Th1-type response, with high levels of gamma interferon (IFN-γ) and low levels of interleukin-4. Two nonameric peptides (Peptide6–14 and Peptide385–393) from Rv1818c were identified by their ability to induce the production of IFN-γ by CD8+ T cells in mice immunized with Rv1818c DNA. An epitope-specific response was demonstrated by the lysis of peptide-pulsed antigen-presenting cells, release of cytotoxic granules and IFN-γ production. These peptides bound with high affinity to MHC H-2Kd and showed low dissociation rates of peptide–MHC complexes. These results could form the basis for testing the identified T-cell epitopes of PE_PGRS proteins in the induction of protective immunity against M. tuberculosis challenge in the mouse model. %U https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.46928-0