Browsing by Author "Al Qublan, Hamzeh"

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    Development and testing of recombinant B. abortus RB51 vaccine strains carrying M. tuberculosis protective antigens
    Al Qublan, Hamzeh (Virginia Tech, 2015-06-23)
    Tuberculosis, caused by Mycobacterium tuberculosis, is one of the most prevalent infectious diseases inflicting humankind. The World Health Organization estimates that one third of the world's population, approximately 2.2 billion people, is infected with TB with a mortality of 1.7 million people annually. Currently, the WHO estimates that each year more than 9 million people develop TB. Bacille Calmette-Guérin (BCG), an attenuated strain of M. bovis, is the only licensed TB vaccine in the world. Clinical studies have shown childhood vaccination with BCG to be protective against disseminating and meningeal forms of TB. However, the efficacy of BCG against pulmonary TB in adults has been variable and inconsistent (0-80%). The objective of this study is to develop and test the efficacy of the B. abortus vaccine strain RB51 as a platform for expression of M. tuberculosis antigens (Ag85B, ESAT6 and Rv2660c) and induction of a protective immune response against M. tuberculosis and B. abortus challenge in mice. Here we report the construction of two recombinant strains of B. abortus vaccine strain RB51 capable of expressing mycobacterial antigens Ag85B, ESAT6 and Rv2660c. Our studies show that expression of mycobacterial antigens in strain RB51 lead to induction of antigen-specific immune responses characterized by secretion of IgG2a antibodies as well as of IFN- and TNF-α. Mice immunized with a combination of two strains of RB51 in equal numbers, one carrying Rv2660c-ESAT6 and another carrying Ag85B, led to a 0.90 log reduction in CFU burden with significance nearly reaching borderline (p = 0.052). However, when mice were primed with the same strains of RB51 and boosted with proteins Ag85B and ESAT6, a significant level of protection (1 log reduction) compared to the PBS vaccinated group was achieved. The protection levels conferred by this vaccination strategy was similar to that conferred by BCG vaccine. In conclusion, we have shown that recombinant RB51 strains expressing mycobacterial protective antigens result in stimulation of antigen specific immune response without altering the vaccine efficacy in protecting against the more virulent strain of B. abortus 2308. These recombinant vaccines could potentially be used to protect against M. tuberculosis infection.
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    Immune Response of Calves Vaccinated with Brucella abortus S19 or RB51 and Revaccinated with RB51
    Dorneles, Elaine Maria S.; Lima, Graciela K.; Teixeira-Carvalho, Andrea; Araujo, Marcio S. S.; Martins-Filho, Olindo A.; Sriranganathan, Nammalwar; Al Qublan, Hamzeh; Heinemann, Marcos B.; Lage, Andrey P. (PLOS, 2015-09-09)
    Brucella abortus S19 and RB51 strains have been successfully used to control bovine brucellosis worldwide; however, currently, most of our understanding of the protective immune response induced by vaccination comes from studies in mice. The aim of this study was to characterize and compare the immune responses induced in cattle prime-immunized with B. abortus S19 or RB51 and revaccinated with RB51. Female calves, aged 4 to 8 months, were vaccinated with either vaccine S19 (0.6–1.2 x 1011 CFU) or RB51 (1.3 x 1010 CFU) on day 0, and revaccinated with RB51 (1.3 x 1010 CFU) on day 365 of the experiment. Characterization of the immune response was performed using serum and peripheral blood mononuclear cells. Blood samples were collected on days 0, 28, 210, 365, 393 and 575 post-immunization. Results showed that S19 and RB51 vaccination induced an immune response characterized by proliferation of CD4+ and CD8+ T-cells; IFN-ɣ and IL-17A production by CD4+ T-cells; cytotoxic CD8+ T-cells; IL-6 secretion; CD4+ and CD8+ memory cells; antibodies of IgG1 class; and expression of the phenotypes of activation in T-cells. However, the immune response stimulated by S19 compared to RB51 showed higher persistency of IFN-ɣ and CD4+ memory cells, induction of CD21+ memory cells and higher secretion of IL-6. After RB51 revaccination, the immune response was chiefly characterized by increase in IFN-ɣ expression, proliferation of antigen-specific CD4+ and CD8+ T-cells, cytotoxic CD8+ T-cells and decrease of IL-6 production in both groups. Nevertheless, a different polarization of the immune response, CD4+- or CD8+-dominant, was observed after the booster with RB51 for S19 and RB51 prime-vaccinated animals, respectively. Our results indicate that after prime vaccination both vaccine strains induce a strong and complex Th1 immune response, although after RB51 revaccination the differences between immune profiles induced by prime-vaccination become accentuated.
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    Multivalent Brucella vaccine for protection against mycobacterial infections and methods of using the same
    (United States Patent and Trademark Office, 2019-09-10)
    Provided herein is a multivalent Brucella vaccine expressing at least one heterologous M. tuberculosis antigen. The vaccines described herein serve as an environmentally safe bivalent vaccine for protection against Brucella and Mycobacterium infections simultaneously. In particular, a multivalent vaccine comprising a Brucella strain transformed with a vector that expresses at least one M. tuberculosis antigen, where the M. tuberculosis antigen(s) is codon optimized for the Brucella strain is provided. In some aspects, the Brucella strain is B. abortus strain RB51 leuB and the M. tuberculosis antigen is one or more of Ag85B, Rv2660c, and ESAT6.
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    Proteomic Analysis of Membrane Blebs of Brucella abortus 2308 and RB51 and Their Evaluation as an Acellular Vaccine
    Araiza-Villanueva, Minerva; Avila-Calderon, Eric Daniel; Flores-Romo, Leopoldo; Calderon-Amador, Juana; Sriranganathan, Nammalwar; Al Qublan, Hamzeh; Witonsky, Sharon G.; Aguilera-Arreola, Ma. Guadalupe; Ruiz-Palma, Maria del Socorro; Ruiz, Enrico A.; Suarez-Gueemes, Francisco; Gomez-Lunar, Zulema; Contreras-Rodriguez, Araceli (2019-11-29)
    Membrane blebs are released from Gram-negative bacteria, however, little is known about Brucella blebs. This work pursued two objectives, the first was to determine and identify the proteins in the membrane blebs by proteomics and in silico analysis. The second aim was to evaluate the use of membrane blebs of Brucella abortus 2308 and B. abortus RB51 as an acellular vaccine in vivo and in vitro. To achieve these aims, membrane blebs from B. abortus 2308 and RB51 were obtained and then analyzed by liquid chromatography coupled to mass spectrometry. Brucella membrane blebs were used as a "vaccine" to induce an immune response in BALB/c mice, using the strain B. abortus RB51 as a positive vaccine control. After subsequent challenge with B. abortus 2308, CFUs in spleens were determined; and immunoglobulins IgG1 and IgG2a were measured in murine serum by ELISA. Also, activation and costimulatory molecules induced by membrane blebs were analyzed in splenocytes by flow cytometry. Two hundred and twenty eight proteins were identified in 2308 membrane blebs and 171 in RB51 blebs, some of them are well-known Brucella immunogens such as SodC, Omp2b, Omp2a, Omp10, Omp16, and Omp19. Mice immunized with membrane blebs from rough or smooth B. abortus induced similar protective immune responses as well as the vaccine B. abortus RB51 after the challenge with virulent strain B. abortus 2308 (P < 0.05). The levels of IgG2a in mice vaccinated with 2308 membrane blebs were higher than those vaccinated with RB51 membrane blebs or B. abortus RB51 post-boosting. Moreover, mice immunized with 2308 blebs increased the percentage of activated B cells (CD19(+)CD69(+)) in vitro. Therefore, membrane blebs are potential candidates for the development of an acellular vaccine against brucellosis, especially those derived from the rough strains so that serological diagnostic is not affected.