A DNA Prime and MVA Boost Strategy Provides a Robust Immunity against Infectious Bronchitis Virus in Chickens

Saponin TQL1055 adjuvant-containing vaccine confers protection upon Mycobacterium tuberculosis challenge in mice

Tuberculosis (TB), caused by the intracellular pathogen Mycobacterium tuberculosis (Mtb), affects the lungs of infected individuals (pulmonary TB) but can also affect other sites (extrapulmonary TB). The only licensed vaccine Mycobacterium bovis bacillus Calmette-Guerin (BCG) protects infants and young children but exhibits variable efficacy in protecting against adult pulmonary TB. Poor compliance and prolonged treatment regimens associated with the use of chemotherapy has contributed to the development of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Mtb. Thus, there is an urgent need for the design of more effective vaccines against TB. The development of safe and novel adjuvants for human use is critical. In this study, we demonstrate that saponin-based TQL1055 adjuvant when formulated with a TLR4 agonist (PHAD) and Mtb specific immunodominant antigens (ESAT-6 and Ag85B) and delivered intramuscularly in mice, the SA-TB vaccine induced potent lung immune responses. Additionally, the SA-TB vaccine conferred significant protection against Mtb infection, comparable with levels induced by BCG. These findings support the development of a SA-TB vaccine comprising TQL1055, as a novel, safe and effective TB vaccine for potential use in humans.

Global Emergence of Infectious Bronchitis Virus Variants: Evolution, Immunity, and Vaccination Challenges

Infectious bronchitis is an acute, extremely contagious viral disease affecting chickens of all ages, leading to devastating economic losses in the poultry industry worldwide. Affected chickens show respiratory distress and/or nephritis, in addition to decrease of egg production and quality in layers. The avian coronavirus, infectious bronchitis virus (IBV), is a rapidly evolving virus due to the high frequency of mutations and recombination events that are common in coronaviruses. This leads to the continual emergence of novel genotypes that show variable or poor crossprotection. The immune response against IBV is complex. Passive, innate and adaptive humoral and cellular immunity play distinct roles in protection against IBV. Despite intensive vaccination using the currently available live-attenuated and inactivated IBV vaccines, IBV continues to circulate, evolve, and trigger outbreaks worldwide, indicating the urgent need to update the current vaccines to control the emerging variants. Different approaches for preparation of IBV vaccines, including DNA, subunit, peptides, virus-like particles, vectored and recombinant vaccines, have been tested in many studies to combat the disease. This review focuses on several key aspects related to IBV, including its clinical significance, the functional structure of the virus, the factors that contribute to its evolution and diversity, the types of immune responses against IBV, and the characteristics of both current and emerging IBV vaccines. The goal is to provide a comprehensive understanding of IBV and explore the emergence of variants, their dissemination around the world, and the challenges to define the efficient vaccination strategies.

Protective RNA nanovaccines against Mycobacterium avium subspecies hominissuis

The induction of an effective immune response is critical for the success of mRNA-based therapeutics. Here, we developed a nanoadjuvant system compromised of Quil-A and DOTAP (dioleoyl 3 trimethylammonium propane), hence named QTAP, for the efficient delivery of mRNA vaccine constructs into cells. Electron microscopy indicated that the complexation of mRNA with QTAP forms nanoparticles with an average size of 75 nm and which have ~90% encapsulation efficiency. The incorporation of pseudouridine-modified mRNA resulted in higher transfection efficiency and protein translation with low cytotoxicity than unmodified mRNA. When QTAP-mRNA or QTAP alone transfected macrophages, pro-inflammatory pathways (e.g., NLRP3, NF-kb, and MyD88) were upregulated, an indication of macrophage activation. In C57Bl/6 mice, QTAP nanovaccines encoding Ag85B and Hsp70 transcripts (QTAP-85B+H70) were able to elicit robust IgG antibody and IFN- ɣ, TNF-α, IL-2, and IL-17 cytokines responses. Following aerosol challenge with a clinical isolate of M. avium ss. hominissuis (M.ah), a significant reduction of mycobacterial counts was observed in lungs and spleens of only immunized animals at both 4- and 8-weeks post-challenge. As expected, reduced levels of M. ah were associated with diminished histological lesions and robust cell-mediated immunity. Interestingly, polyfunctional T-cells expressing IFN- ɣ, IL-2, and TNF- α were detected at 8 but not 4 weeks post-challenge. Overall, our analysis indicated that QTAP is a highly efficient transfection agent and could improve the immunogenicity of mRNA vaccines against pulmonary M. ah, an infection of significant public health importance, especially to the elderly and to those who are immune compromised.