Glucan-Chitin Particles Enhance Th17 Response and Improve Protective Efficacy of a Multivalent Antigen (rCpa1) against Pulmonary Coccidioides posadasii Infection

Abstract

Developing an effective and safe recombinant vaccine requires microbe-specific antigens combined with an adjuvant/delivery system to strengthen protective immunity. In this study, we designed and expressed a multivalent, recombinant polypeptide antigen (rCpa1) that consists of three previously identified antigens (i.e., Ag2/Pra, Cs-Ag and Pmp1) and 5 pathogen-derived peptides with high affinity for human MHC II molecules. The purified rCpa1 was encapsulated into four types of yeast cell-wall particles containing various compositions of β-glucan, mannan and chitin or mixed with an oligonucleotide (ODN) containing 2 methylated dinucleotide CpG motifs. This multivalent antigen encapsulated into glucan-chitin particles (GCP-rCpa1) showed a significantly elevated reduction of fungal burden for human HLA-DR4 transgenic mice compared to the other tested adjuvant-rCpa1 formulations. Among the tested adjuvants GCPs and GPs were both capable of stimulating a mixed Th1 and Th17 response. Mice vaccinated with GCP-rCpa1 showed elevated IL-17 production in T-cell recall assays and early lung infiltration of activated Th1 and Th17 cells compared to GP-rCpa1-vaccinated mice. Both C57BL/6 and HLA-DR4 transgenic mice that were vaccinated with GCP-rCpa1 vaccine increased surivial compared to the mice received GCPs alone. Concurringly, GCP-rCpa1 vaccine stimulated enhanced infiltration of macrophages to engulf and process the vaccine for antigen presentation in the injection sites compared to GP-rCpa1 injection. This is the first attempt to systematically characterize the presentation of a multivalent coccidioidomycosis vaccine encapsulated with selected adjuvants which enhance protective cellular immune response to infection.

Antigen discovery unveils resident memory and migratory cell roles in antifungal resistance

“…10 μg of Bl-Eng2 was loaded into GCPs and mice were vaccinated SC or IN three times, two weeks apart as described (Hung et al, 2018), unless otherwise indicated. In some experiments, mice were vaccinated twice either SC with 10 μg Bl-Eng2 formulated in CFA or IFA, or IN with 10 μg Bl-Eng2 in 10% Adjuplex (Empirion, LLC, Columbus OH), two weeks apart.…”

Proper Care and Feeding of Coccidioides: A Laboratorian's Guide to Cultivating the Dimorphic Stages of C. immitis and C. posadasii

“…Current Protocols in Microbiology respectively. These results demonstrate that CD1 mice are more resistant to infection with Coccidioides compared to other mouse strains, such as BALB/c or C57BL/6 (Cox, Kennell, Boncyk, & Murphy, 1988;Hung, Zhang, et al, 2018;Magee & Cox, 1995).…”

“…Commonly used and cited laboratory strains are C. posadasii C735 and Silveira (NR-48944) and C. immitis RS (NR-48942) and 2006 (NR-48934). We also recommend the attenuated strain C. posadasii cts2/ ard1/ cts3 , which can be handled in a biosafety level 2 (BSL-2) environment and has been extensively characterized in vitro and in vivo (Hung, del Pilar Jimenez-Alzate, et al, 2014;Hung, Zhang, et al, 2018;Hung, Castro-Lopez, & Cole, 2014;Hung, Gonzalez, Wuthrich, Klein, & Cole, 2011;Mead, Roe, et al, 2020;Mead, Teixeira, Galgiani, & Barker, 2019;Xue et al, 2009). Isolates arrive as a 1-ml glycerol stock that should be stored at -80°C until use.…”

A novel vaccine platform using glucan particles for induction of protective responses againstFrancisella tularensisand other pathogens

“…Identification of immunologically relevant epitopes aids the development of recombinant peptides/polypeptides that can be encapsulated within GPs for generating antigen‐specific protective immunity. For example, recombinant chimeric poly‐epitope antigen (rCpa1), consisting of a combination of three different antigens and five MHC‐II binding pathogen‐derived peptides, was designed for a C. posadasii vaccine . When administered together with a TLR ‐ 9 agonist [DNA containing unmethylated cytosine–phosphate–guanine oligonucleotides (CpG‐ODN)], a non‐protective immune response was induced in a humanized human leucocyte antigen (HLA)‐DR4 transgenic mouse model.…”