An unbiased peptide-wide discovery approach to select Mycobacterium tuberculosis antigens that target CD8+ T cell response during infection.
Accruing data strongly support the possible role of CD8+ T cells in immunity against tuberculosis (TB). Multivalent vaccines against Mycobacterium tuberculosis (Mtb) that incorporate CD8+ T cell antigens with those that elicit CD4+ T cells are therefore highly desirable. To screen for potential CD8+ T cell antigens that are produced by Mtb during infection, we isolated pathogen-derived peptides that bound to MHC Class I molecules expressed in adherent splenocytes obtained from Mtb-infected mice. Mass spectroscopy analysis revealed the following four nonamer peptides that had 100% homology with Mtb proteins: DGYVGAPAH (MT_0401), TTMPLFAD (MT_1164), RSGAATPVR (MT_2160.1) and LAAVVGVVL (MT_0078). The gene MT_0401 codes the protein 5'-phosphoribosylglycinamide transformylase 2 and the other three genes code for hypothetical proteins with unknown function. The NCBI/Blast analysis showed that among the four peptides DGYVGAPAH had the highest maximum alignment score and lowest E value (number of alignments expected by chance). Therefore, we assessed whether MT_0401 expressed in two genetic vaccine formulations was capable of stimulating CD8+ T cell response that is specific to DGYVGAPAH peptide. When mice were immunized with a recombinant plasmid DNA and an E1/E3-deleted Adenovirus 5 expressing MT0401 protein, using both homologous and heterologous prime-boost protocols, they developed strong DGYVGAPAH-specific CD8+ T cell response as well as antibody and CD4+ specific T cell response to the full length MT0401 protein. Equally important was the observation that mice infected with Mtb developed DGYVGAPAH-specific CD8+ T cell responses in both spleen and lungs. These results demonstrate that Mtb antigens that are processed and presented via MHC Class I machinery can be readily identified by the described approach and may be useful candidate antigens to stimulate specific CD8+ T cell responses in vaccine development programs.
Global Infectious Disease Research Center, The Forsyth Institute, 245 First Street, Cambridge, MA 02142, USA; Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA 02115, USA.
Mark J
MJ
Cayabyab
Lizeng
L
Qin
Suely S
SS
Kashino
Angelo
A
Izzo
Antonio
A
Campos-Neto
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D008168:Lung / Q000276:immunology; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D013154:Spleen / Q000276:immunology; D014376:Tuberculosis / Q000276:immunology* / Q000382:microbiology*; D032581:Tuberculosis Vaccines / Q000008:administration & dosage / Q000276:immunology* / Q000302:isolation & purification; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology / Q000302:isolation & purification
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D010455:Peptides; D032581:Tuberculosis Vaccines; D014614:Vaccines, Synthetic; C072681:Mycobacterium tuberculosis antigens
CD8 associated antigen; Immunogenicity; MT0401; Tuberculosis