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Elucidation of structural activity relationships of Lipid A-based | 59862
Immunological Disorders and Immunotherapy

Immunological Disorders and Immunotherapy
Open Access

ISSN: 2593-8509

Elucidation of structural activity relationships of Lipid A-based TLR4 mimetic adjuvants in a bacterial subunit vaccine


4th European Congress on VACCINES AND IMMUNOLOGY

October 04-05, 2021 Webinar

*Jerilyn R. Izaca, Matthew E. Shermana, Etsuro Nanishib,c, Timothy R. O‚??Mearab,c, David J. Variscoa, Jocelynn Duvalla, Richard D. Smitha, Alison J. Scotta, David J. Dowlingb, c and Robert. K. Ernsta

University of Maryland Baltimore, USA
Boston Children‚??s Hospital, USA
Harvard Medical School, USA

Scientific Tracks Abstracts: IDIT

Abstract :

Background: Immunoadjuvants are key components in vaccine formulations that enhance and shape immune responses to vaccines. We have previously demonstrated the ability to rapidly generate novel lipid A (LA) structures with potent adjuvant capabilities using Bacterial Enzymatic Combinatorial Chemistry (BECC). BECC utilizes expression or deletion of enzymes involved in the LA synthesis pathway for Gram-negative bacteria to purify TLR4 without further modifi cations. In this study, we evaluated 12 structurally different BECC molecules and tested their adjuvant capabilities in vitro and in in vivo models. All BECC molecules were tested for induction of NF-kb in immortalized murine and human cells and TNF-a, in pbmcs obtained from adult and elderly volunteers. To determine in vivo effi cacy, C57BL/6 mice were vaccinated with each adjuvant and the recombinant Y. Pestis F1-V antigen in a prime-boost model. We also tested these adjuvants in an Infl uenza H1N1 challenge model using hemagglutinin as the antigen in BALB/c mice. Survival and weight loss were used to assess protective effi cacy. Additionally, antibody levels and isotyping were measured to compare all adjuvant/ antigen combinations. Splenocytes were harvested in immunized mice and cytokine production was assessed via Luminex. Results and Conclusions: The most and least immunostimulatory molecules in vitro did not provide complete protection during challenge, demonstrating an optimal range of stimulation is needed for TLR4-mimetic adjuvants. Based on the splenocyte restimulation assay, different memory responses were produced depending on structure. The data from this study elucidates structure- activity mechanisms by evaluating adjuvant capability both in vitro and in vivo. Based on lipid A structure, we found signifi cant differences in antibody production, isotype generation, stimulation of pbmcs and in vitro cell lines, as well as protective effi cacy that was structure dependent. Future research includes investigating these adjuvants in humanized mice that have been genetically engineered to have the htlr4/hmd-2 pathway.

Biography :

Jerilyn R. Izac is currently working as a Microbiologist at National Institute of Standards and Technology (NIST), USA. She received her Post-Doctoral Degree from the University of Maryland Baltimore, USA. Her research mainly focusses on Microbiology and Immunology related areas.

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