rBCG induces strong antigen-specific T cell responses in rhesus macaques in a prime-boost setting with an adenovirus 35 tuberculosis vaccine vector

• Published in: PloS one Vol. 3; no. 11; p. e3790
• Main Authors: Magalhaes, Isabelle, Sizemore, Donata R, Ahmed, Raija K, Mueller, Stefanie, Wehlin, Lena, Scanga, Charles, Weichold, Frank, Schirru, Giulia, Pau, Maria Grazia, Goudsmit, Jaap, Kühlmann-Berenzon, Sharon, Spångberg, Mats, Andersson, Jan, Gaines, Hans, Thorstensson, Rigmor, Skeiky, Yasir A W, Sadoff, Jerry, Maeurer, Markus
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 21.11.2008; Public Library of Science (PLoS)
• Subjects: Adenoviridae - genetics; Adenoviruses; Animals; Antigens; Antigens, Bacterial - genetics; Bacillus Calmette-Guerin vaccine; Bacterial Toxins - genetics; BCG; BCG Vaccine - administration & dosage; BCG Vaccine - genetics; Blood; Blood cells; CD4 antigen; Cell proliferation; Combined vaccines; Cytokines; Disease control; Drug delivery systems; Female; Fusion protein; Genetic Vectors; Hemolysin Proteins - genetics; Hepatitis; Immune response; Immune response (cell-mediated); Immunity, Cellular; Immunization, Secondary; Immunology; Immunology/Immune Response; Immunology/Immunity to Infections; Infections; Infectious Diseases; Infectious Diseases/Bacterial Infections; Infectious Diseases/Respiratory Infections; Interferon; Interferon-gamma - biosynthesis; Interleukin 2; Leishmania major; Lymphocyte Activation; Lymphocytes; Lymphocytes T; Macaca mulatta; Medicin och hälsovetenskap; Monkeys & apes; Peripheral blood mononuclear cells; Plasmodium falciparum; Proteins; Recombinant proteins; Replicating; Replication; T cells; T-Lymphocytes - immunology; Tuberculosis; Tuberculosis vaccines; Tuberculosis Vaccines - genetics; Tumor necrosis factor; Tumor necrosis factor-α; Vaccination; Vaccines; Vaccines, Synthetic - administration & dosage; Vaccines, Synthetic - genetics; United States > US; Maryland; Sweden
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0003790

BCG vaccination, combined with adenoviral-delivered boosts, represents a reasonable strategy to augment, broaden and prolong immune protection against tuberculosis (TB). We tested BCG (SSI1331) (in 6 animals, delivered intradermally) and a recombinant (rBCG) AFRO-1 expressing perfringolysin (in 6 animals) followed by two boosts (delivered intramuscullary) with non-replicating adenovirus 35 (rAd35) expressing a fusion protein composed of Ag85A, Ag85B and TB10.4, for the capacity to induce antigen-specific cellular immune responses in rhesus macaques (Macaca mulatta). Control animals received diluent (3 animals). Cellular immune responses were analyzed longitudinally (12 blood draws for each animal) using intracellular cytokine staining (TNF-alpha, IL-2 and IFN-gamma), T cell proliferation was measured in CD4(+), CD8alpha/beta(+), and CD8alpha/alpha(+) T cell subsets and IFN-gamma production was tested in 7 day PBMC cultures (whole blood cell assay, WBA) using Ag85A, Ag85B, TB10.4 recombinant proteins, PPD or BCG as stimuli. Animals primed with AFRO-1 showed i) increased Ag85B-specific IFN-gamma production in the WBA assay (median >400 pg/ml for 6 animals) one week after the first boost with adenoviral-delivered TB-antigens as compared to animals primed with BCG (<200 pg/ml), ii) stronger T cell proliferation in the CD8alpha/alpha(+) T cell subset (proliferative index 17%) as compared to BCG-primed animals (proliferative index 5% in CD8alpha/alpha(+) T cells). Polyfunctional T cells, defined by IFN-gamma, TNF-alpha and IL-2 production were detected in 2/6 animals primed with AFRO-1 directed against Ag85A/b and TB10.4; 4/6 animals primed with BCG showed a Ag85A/b responses, yet only a single animal exhibited Ag85A/b and TB10.4 reactivity. AFRO-1 induces qualitatively and quantitatively different cellular immune responses as compared with BCG in rhesus macaques. Increased IFN-gamma-responses and antigen-specific T cell proliferation in the CD8alpha/alpha+ T cell subset represents a valuable marker for vaccine-take in BCG-based TB vaccine trials.