Biology subjects

Deora, R.

Publications and source records attributed to Deora, R..

3 recordsLinked to original sources

bioRxiv2022

Prime-pull immunization of mice with a BcfA-adjuvanted vaccine elicits mucosal immunity and prevents SARS CoV-2 infection and pathology

Vaccines against SARS-CoV-2 that induce mucosal immunity capable of preventing infection and disease remain urgently needed. We show that intramuscular priming of mice with an alum and BcfA-adjuvanted Spike subunit vaccine, followed by a BcfA-adjuvanted mucosal booster, generated Th17 polarized tissue resident CD4+ T cells, and mucosal and serum antibodies. The serum antibodies efficiently neutralized SARS-CoV-2 and its Delta variant, suggesting cross-protection against a recent variant of concern (VOC). Immunization with this heterologous vaccine prevented weight loss following challenge with mouse-adapted SARS-CoV-2 and reduced viral replication in the nose and lungs. Histopathology showed a strong leukocyte and polymorphonuclear (PMN) cell infiltrate without epithelial damage in mice immunized with BcfA-containing vaccines. In contrast, viral load was not reduced in the upper respiratory tract of IL-17 knockout mice immunized with the same formulation, suggesting that the Th17 polarized T cell responses are critical for protection. We show that vaccines adjuvanted with alum and BcfA, delivered through a heterologous prime-pull regimen, protect against SARS-CoV-2 infection without causing enhanced respiratory disease. SIGNIFICANCEThere remains a need for SARS CoV-2 booster vaccines that generate mucosal immunity and prevent transmission. We show that systemic priming followed by a mucosal booster with a BcfA-adjuvanted subunit vaccine generates neutralizing antibodies and Th17 polarized systemic and tissue-resident immune responses that provide sterilizing immunity against wildtype SARS CoV-2, and a variant of concern. Importantly, in contrast to alum alone, the addition of BcfA prevents respiratory pathology. These results suggest that a BcfA-adjuvanted mucosal booster may elicit mucosal immunity in individuals previously immunized systemically with approved vaccines. This foundational study in mice sets the stage for testing our vaccine regimen in larger animal models as a booster vaccine.

immunology↗

bioRxiv2022

Bps polysaccharide of Bordetella pertussis resists antimicrobial peptides by functioning as a dual surface shield and decoy and converts Escherichia coli into a respiratory pathogen.

Infections and disease caused by the obligate human pathogen Bordetella pertussis (Bp) are increasing, despite widespread vaccinations. The current acellular pertussis vaccines remain ineffective against nasopharyngeal colonization, carriage, and transmission. In this work, we tested the hypothesis that Bordetella polysaccharide (Bps), a member of the poly-{beta}-1,6-A-acetyl-D-glucosamine (PNAG/PGA) family of polysaccharides promotes respiratory tract colonization of Bp by resisting killing by antimicrobial peptides (AMPs). Genetic deletion of the bpsA-D locus, as well as treatment with the specific glycoside hydrolase Dispersin B, increased susceptibility to AMP-mediated killing. Bps was found to be both cell surface-associated and secreted during laboratory growth and mouse infections. Addition of bacterial supernatants containing Bps and purified Bps increased B. pertussis resistance to AMPs. By utilizing ELISA, immunoblot and flow cytometry assays, we show that Bps functions as a dual surface shield and decoy by inhibiting AMP binding. Co-inoculation of C57BL/6J mice with a Bps-proficient strain enhanced respiratory tract survival of the Bps-deficient strain. In combination, the presented results highlight the critical role of Bps as a central driver of B. pertussis pathogenesis. Heterologous production of Bps in a non-pathogenic E. coli K12 strain increased AMP resistance in vitro, and augmented bacterial survival and pathology in the mouse respiratory tract. Therefore, by conferring virulence traits across bacterial genera, Bps transforms a primarily intestinal and urinary tract bacterium into a respiratory pathogen. These studies can serve as a foundation for other PNAG/PGA polysaccharides and for the development of an effective Bp vaccine that includes Bps. Author summaryPertussis or whooping cough, caused by the obligate human pathogen Bordetella pertussis (Bp), is resurging in many countries. Currently, the mechanism by which B. pertussis subverts and resists host immunity is poorly known. In this manuscript, we examined the role of the B. pertussis polysaccharide Bps in promoting resistance to antimicrobial peptides (AMPs), a critical component of host immune defense. We show that the presence of Bps on the bacterial cell surface enhanced AMP resistance. Bps was secreted both during bacterial growth and during mouse infections. We further found that Bps functioned both as a surface shield and decoy, thereby inhibiting AMP binding. Simultaneous infection of mice with Bps-proficient and Bps- deficient strains resulted in greater survival of the Bps-deficient strain in the mouse respiratory tract. Finally, production of Bps in a non-pathogenic E. coli strain increased AMP resistance in vitro, and increased bacterial survival and heightened pathology in the mouse respiratory tract. Our study provides new insights into how B. pertussis has evolved to survive in the mammalian respiratory tract. Additionally, these studies underscore the potential of a single virulence factor to convert a non-pathogenic bacterium into a respiratory tract pathogen.

microbiology↗

bioRxiv2019

Bordetella Colonization Factor A (BcfA) elicits protective immunity against Bordetella bronchiseptica in the absence of an additional adjuvant

Bordetella bronchiseptica (B. bronchiseptica) is an etiologic agent of respiratory diseases in animals and humans. Despite widespread use of veterinary B. bronchiseptica vaccines, there is limited information on their composition, relative efficacy, and the immune responses they elicit. Furthermore, human B. bronchiseptica vaccines are not available. We leveraged the dual antigenic and adjuvant functions of BcfA to develop acellular B. bronchiseptica vaccines in the absence of an additional adjuvant. Balb/c mice immunized with BcfA alone or a trivalent vaccine containing BcfA and the Bordetella antigens FHA and Prn were equally protected against challenge with a prototype B. bronchiseptica strain. The trivalent vaccine protected mice significantly better than the canine vaccine Bronchicine(R) and provided protection against a B. bronchiseptica strain isolated from a dog with kennel cough. Th1/17-polarized immune responses correlate with long-lasting protection against Bordetellae and other respiratory pathogens. Notably, BcfA strongly attenuated the Th2 responses elicited by FHA/Prn, resulting in Th1/17-skewed responses in inherently Th2-skewed Balb/c mice. Thus, BcfA functions as both an antigen and an adjuvant, providing protection as a single component vaccine. BcfA-adjuvanted vaccines may improve the efficacy and durability of vaccines against Bordetellae and other pathogens.

immunology↗