Author Of 1 Presentation
P0673 - Induction of human IL-10 and protection against murine EAE by a manufactured human gut derived microflora antigen (ID 734)
Abstract
Background
The intestinal microbiota and products are pivotal regulators of the immune system at local and systemic levels. We have shown that a purified form of polysaccharide-A (PSA) produced by the intestinal Gram-negative Bacteroides fragilis @ 100 μg once every three days conferred protection against the central nervous system (CNS) inflammatory demyelination induced in the experimental autoimmune encephalomyelitis (EAE) murine model of multiple sclerosis.
Objectives
To determine if a GMP manufactured PSA could induce immune protection against murine EAE and indicators of immune regulation by human PBMC in vitro.
Methods
PSA was prepared in a GMP commercial facility and compared by immune assay and NMR spectroscopy to the purified PSA previously reported to protect against EAE (Ochoa-Reparaz et. al. Mucosal Immunol 2010). Manufactured PSA was administered using the C57BL/6 model of EAE. A control (PBS) and two dose range (100 and 300μg) of PSA were administered per os once 3 days before and every 3 days post disease induction in ten-week-old female C57BL6 mice (n = 12 per group). Treatment was carried out q3 days for a 30-day period. The body weight changes, EAE clinical scores, and other disease parameters such as disease onset, cumulative scores, and severity scores were compared among groups.
Results
There was no evidence of clinical adverse events to oral treatment with PSA and moreover no effect on the body weight of mice. The treatment with PSA-100 was protective against EAE when compared to PBS control (Area under curve: p = 0.0218). The level of protection was not statistically improved by the oral administration of 300 mg PSA. Protection with PSA-100 was evidenced by the reduced overall severity of disease (p < 0.0001), mortality rate (5/12 mice in PBS-treated. vs. 0/12 in PSA-treated) cumulative EDSS scores (p = 0.0212), and severity indexes (p = 0.0196). The manufactured PSA was then used in a human PBMC stimulation study. Earlier studies indicated that PSA amplifies the conversion to human IL-10 secreting Foxp3 T regulatory cells (Burgess J. et. al Ann Clinical Translational Neurol 2017). Upon exposure to the manufactured PSA, in vitro isolated T cell/DC produced substantial increases in IL-10 production in both HC (p=0.0011) and untreated MS (p=0.0039) as measured by ELISA. Further, there was no PSA haplotype restriction to human IL-10 production as measured by ELISPOT using 20 healthy PBMC donors of known HLA haplotype.
Conclusions
These studies recapitulate our previous reports demonstrating a robust regulatory effect by a native gut commensal antigen isolated from B. fragilis with a commercially prepared biosimilar molecule. The manufactured PSA shared biochemical and immunologic properties consistent with native molecule. These studies suggest a novel class of oral therapy for treating CNS demyelinating disease in humans can be achieved via induction of immune regulation by a single microbial antigen derived from the gut microbiome