PolyIC Immune Priming Protocols for Oysters
A short non-peer-reviewed scientific report
This report is a Methods Note. It has not been peer reviewed.
It is shared to make small scientific efforts, preliminary analyses, technical observations, and exploratory work openly available.
1 Overview
Poly(I:C) is a non-infectious elicitor and viral mimic in the form of synthetic double-stranded RNA (dsRNA). Poly(I:C) is a synthetic, double-stranded RNA molecule (polyribonucleotide) that has been widely used to induce a type I interferon (IFN) response in many species.
In oysters, it has been shown to produce a protective immune response (Lafont et al. 2023; Green and Montagnani 2013; Martins et al. 2020; Lorgeril et al. 2018).
2 Previous Protocols in the Roberts Lab
Matt George conducted previous work with PolyIC using injection methods in the lab. He ran tests comparing water bath vs. injection protocols, documented in his notebook (Parts 1, 2, and 3). In his tests, Matt used the following approach:
“10 diploid and 10 triploid oysters (naive) were added to an emersion bath containing 500 mL of seawater containing 10 µg/mL Poly(I:C), with a bubbler. Lafont et al. 2017 found that emersion at 38 µg/mL worked for 24 hrs, so we will see.”
Matt did not have follow-up documented in his notebook; Ariana Huffmyer will reach out to determine the results.
3 Water Bath/Emersion Protocols in the Literature
One study has used emersion protocols for PolyIC exposure in oysters. (Lafont et al. 2023) found that emersion in PolyIC provided equal protection to injection methods, which are more commonly used. Injection protocols require anesthesia followed by direct injection into oyster tissues. If a water bath with PolyIC works equally well, it represents a much simpler and less invasive protocol.
In one of their experiments, (Lafont et al. 2023) exposed 20 oysters to either 0.76 µg/mL or 0.38 µg/mL PolyIC in 100 mL of seawater for 2.5 hours. Oysters then recovered in seawater for 24 hours before being challenged with pathogens (OsHV-1 or heat-killed Vibrio) to test immune response over 8 days.
Results showed that survival was higher with PolyIC regardless of dose (~90% survival) compared to unprimed controls (~50% survival). This was comparable to survival observed with a high dose of injected PolyIC (~85% survival).
4 Suggested Protocol for Point Whitney
Based on Matt George’s preliminary tests and the (Lafont et al. 2023) study, the following emersion parameters are proposed for oysters at Point Whitney:
- Concentration: 0.38 µg/mL Poly(I:C) in seawater
- Duration: 2.5 hour emersion
Manufacturer’s instructions for mixing Poly(I:C) solutions should be reviewed before implementation, as this reagent has not been used previously in this lab context.
5 Suggested citation
Huffmyer, A. S., and S. B. Roberts. 2024. PolyIC Immune Priming Protocols for Oysters. Current Findings. Available at: https://robertslab.github.io/current-findings/reports/polyic-immune-priming-protocols/
6 Version history
| Version | Date | Notes |
|---|---|---|
| 0.1 | 2026-06-17 | Migrated from “PolyIC Immune Priming Protocols – Ariana S Huffmyer – Research Scientist, University of Washington.pdf” |