Biology subjects

Nagalingam, G.

Publications and source records attributed to Nagalingam, G..

3 recordsLinked to original sources

bioRxiv2020

Advax adjuvant formulations promote protective immunity against aerosol Mycobacterium tuberculosis in the absence of deleterious inflammation and reactogenicity

The development of safe and effective adjuvants is a critical goal of vaccine development programs. In this report, we defined the immunostimulatory profile and protective effect against aerosol Mycobacterium tuberculosis infection of vaccine formulations incorporating the semi-crystalline adjuvant {delta}-inulin (Advax). Advax formulated with CpG oligonucleotide and the QS-21 saponin (AdvaxCpQS) was the most effective combination, demonstrated by the capacity of CysVac2/AdvaxCpQS to significantly reduce the bacterial burden in the lungs of M. tuberculosis-infected mice. CysVac2/AdvaxCpQS protection was associated with rapid influx of neutrophils, macrophages and monocytes to the site of vaccination and the induction of antigen-specific IFN-{gamma}+/IL-2+/TNF+ polyfunctional CD4+ T cells in the lung. When compared to the highly potent adjuvant combination of monophosphoryl lipid A and dimethyldioctadecylammonium bromide (MPL/DDA), AdvaxCpQS imparted a similar level of protective efficacy yet without the profound stimulation of inflammatory cytokines and vaccination site ulceration observed with MPL/DDA. Addition of DDA to CysVac2/ AdvaxCpQS further improved the protective effect of the vaccine, which correlated with increased polyfunctional CD4+ T cells in the lung but with no increase in vaccine reactogenicity. The data demonstrate that Advax formulations can decouple protective tuberculosis immunity from reactogenicity, making them ideal candidates for human application. HighlightsO_LIAdvax adjuvant formulations improve pulmonary protection against aerosol Mycobacterium tuberculosis infection C_LIO_LIDifferent combinations of adjuvant components markedly influence the level of protection observed C_LIO_LIProtection is associated with the rapid influx of myeloid cells to the site of vaccination and the induction of antigen-specific polyfunctional CD4+ T cells in the lung. C_LIO_LIAdvax formulations abrogate vaccine-site ulceration and inflammatory cytokine production C_LI

immunology↗

bioRxiv2020

Mucosal vaccination with CysVac2/Advax induces Th17 lung-resident CD4+ T cells and interleukin-17-dependant protection against Mycobacterium tuberculosis infection

The development of effective vaccines against bacterial lung infections requires the induction of protective, pathogen-specific immune responses without deleterious inflammation within the pulmonary environment. Here, we made use of a polysaccharide-adjuvanted vaccine approach to elicit resident pulmonary T cells to protect against aerosol Mycobacterium tuberculosis infection. Intratracheal administration of the multistage fusion protein CysVac2 and the delta-inulin adjuvant Advax (formulated with a TLR9 agonist) provided superior protection against aerosol M. tuberculosis infection in mice, compared to parenteral delivery. Surprisingly, removal of the TLR9 agonist did not impact vaccine protection despite a reduction in cytokine-secreting T cell subsets, particularly CD4+ IFN-{gamma}+IL-2+TNF+ multifunctional T cells. CysVac2/Advax-mediated protection was associated with the induction of lung-resident, antigen-specific memory CD4+ T cells that expressed IL-17 and ROR{gamma}t, the master transcriptional regulator of Th17 differentiation. IL-17 was identified as a key mediator of vaccine efficacy, with blocking of IL-17 during M. tuberculosis challenge reducing phagocyte influx, suppressing priming of pathogen-specific CD4+ T cells in local lymph nodes and ablating vaccine-induced protection. These findings suggest that tuberculosis vaccines such as CysVac2/Advax that are capable of eliciting Th17 lung-resident memory T cells are promising candidates for progression to human trials. ImportanceMycobacterium tuberculosis, the causative agent of tuberculosis (TB), kills more individuals each year than any other single pathogen. The only approved vaccine, BCG, administered intradermally, is unreliable in protecting against pulmonary TB, therefore a more effective vaccine is critical for global control of the disease. Vaccination in the lung would be a rational way of inducing a local memory immune response to TB, however vaccine platforms would need to deliver antigens to delicate mucosal surfaces without inducing deleterious inflammatory responses. We developed a safe mucosal vaccine which induced protection against TB lung infection in mice by inducing high levels of lung-resident T cells expressing the cytokine IL-17. Removal of IL-17 limited the influx of phagocytic cells to the lung and completely ablated protection afforded by the vaccine. This study provides new insights into mechanisms of protection against M. tuberculosis and provides a promising candidate to protect against TB in humans.

immunology↗

bioRxiv2018

Discovery of antimicrobial compounds from Lendenfeldia, Ircinia and Dysidea sponges using bioassay guided fractionation of marine extracts

Multidrug resistant bacteria have emerged as a threat to public health all over the world. At the same time, the discovery of new bioactive small molecules with antimicrobial activity and suitable pharmacological properties has waned. Herein we report the screening of marine extracts to identify novel compounds with antimicrobial activity. Bioassay guided fractionation has enabled the discovery and identification of a family of simple amines with promising activity against methicillin resistant Staphylococcus aureus (MRSA). To confirm the natural product structures proposed, these compounds and analogues have been prepared synthetically. Several of the synthetic analogues showed promising bioactivity against the medically important pathogens MRSA (MICs to 12.5 {micro}M), Mycobacterium tuberculosis (MICs to 0.02 {micro}M), uropathogenic Escherichia coli (MIC 6.2 {micro}M) and Pseudomonas aeruginosa (MIC 3.1 {micro}M). Cross-referencing antimicrobial activity and toxicity show that these synthetic compounds display a favourable therapeutic index for their target pathogens.

developmental biology↗