Clinical Microbiology: Open Access

Evaluation of four antigen delivery systems for the induction of antigen-specific and protective cellular immune responses to major Mycobacterium tuberculosis-specific antigens

8^thGlobal Summit on Microbiology and Infectious Diseases

February 22-23, 2018 | Paris, France

Hussain A Safar

Kuwait University, Kuwait

Posters & Accepted Abstracts: Clin Microbiol

Abstract:

Introduction & Aim: The only vaccine for tuberculosis is BCG, but it has several limitations including no effect against adult pulmonary tuberculosis, interference with diagnostic efficacy of tuberculin and ability to cause disease in HIV-infected people. In the search for new vaccines, several Mycobacterium tuberculosis-specific antigens as potential vaccine candidates have been identified. However, the delivery of these antigens is an important issue. The aim of this study was to test four delivery systems, i.e. two chemical adjuvants, a non-pathogenic mycobacterium (Mycobacterium vaccae) and a DNA vaccine vector, for induction of protective and pathologic cellular immune responses to major Mycobacterium tuberculosis-specific antigens esxO, esxP, esxV esxW and PE35. Method: The target genes were cloned into expression plasmids to obtain recombinant (r) proteins, r-Mycobacterium vaccae and rDNA vaccines. Mice were immunized and boosted with: (1) r-proteins emulsified in two chemical adjuvants, (2) r-Mycobacterium vaccae and (3) r-DNA vaccines. Mice were sacrificed and the splenocytes were stimulated in vitro with peptides covering the sequence of immunizing proteins. The culture supernatants were assayed for the protective Th1 cytokine IFN-γ and the pathologic Th2 (IL-5), Treg (IL-10) and Th-17 (IL-17A) cytokines in ELISA. Result: The mice immunized with the proteins emulsified with a chemical adjuvant and rDNA vaccines showed positive responses to the peptide pools of ESXO, ESXV and PE35 in protective Th1 assays but not in pathologic Th2, Treg and Th17 assays. Conclusion: Appropriate delivery systems are required to induce protective cellular immune responses using the major Mycobacterium tuberculosis-specific antigens as vaccine candidates.

Biography :

Hussain A Safar is a PhD candidate at Kuwait University, Kuwait. His area of specialization is Medical Microbiology and specifically in Bacterial Immunology. He has participated in more than three conferences and won four best poster awards in the past two years.