Nanoparticle Vaccine Candidate Offers New Hope Against Hepatitis C Virus

Investigators at Scripps Research have engineered the first stable, soluble versions of hepatitis C virus’ (HCV) challenging surface proteins and mounted them on self-assembling nanoparticles. The study authors, who published their findings in Nature Communications, noted that this is a breakthrough that may finally unlock a viable vaccine against a disease that has eluded researchers for decades.¹

HCV infects approximately 50 million individuals worldwide and is a leading cause of liver cirrhosis and hepatocellular carcinoma, according to the World Health Organization (WHO). Although direct-acting antiviral (DAA) drugs achieve sustained virological response rates above 95%, their high cost, limited global access, and inability to prevent reinfection have left a critical gap in the fight against HCV.^2-4

Despite 3 decades of effort, no approved HCV vaccine exists, largely because the 2 proteins that coat the viral surface, E1 and E2, misfold or fall apart when removed from the virus, making them nearly impossible to deploy in traditional vaccine formats.^5,6

Engineering Stability: What Investigators Found

The team, led by Jiang Zhu, PhD, a professor in the Department of Integrative Structural and Computational Biology, used cryo-electron microscopy (cryo-EM) structural data to engineer a soluble, stabilized version of the HCV-1 E1E2 complex, a design milestone that researchers have pursued for more than 20 years.⁷

The researchers trimmed unstable, flexible regions of the proteins, including a putative fusion peptide in E1, and introduced molecular scaffolds that locked E1 and E2 into their native orientation. The resulting construct maintained authentic structural features, including strong binding to the broadly neutralizing antibody (bNAb) AR4A, which recognizes a conserved region on the viral surface.^1,7

“Normally, these glycoproteins are extremely fragile,” Zhu said in a press release. “In the redesigned version, they became rock solid while keeping the same shape the immune system requires to recognize them.”⁷

Mounting the Antigen: The SApNP Platform

After stabilizing the E1E2 complex, the team displayed 60 copies of the protein on Zhu’s proprietary self-assembling protein nanoparticle (SApNP) platform, a modular system that clusters multiple antigen copies in a virus-like arrangement to amplify immune recognition.^1,7

Variations of the SApNP system have previously been applied to HIV; influenza viruses; Ebola viruses, including Sudan ebolavirus; and Marburg virus, demonstrating the platform’s versatility across structurally diverse pathogens.^1,7

When tested in mouse models, HCV nanoparticle vaccine candidates with wild-type or modified glycans, including glycan-trimmed constructs designed to expose additional neutralizing epitopes, triggered immune responses targeting the viral surface.¹

Why This Matters for Pharmacists

As frontline health care providers and vaccine administrators, pharmacists stand at a pivotal intersection of patient counseling and public health.

Immunity through successful DAA treatment is insufficient to prevent reinfection in individuals with ongoing risky behaviors. High-risk groups such as people who inject drugs have shown 18-month reinfection rates of up to 17 per 100 person-years after treatment. A preventive vaccine would represent a fundamentally different tool, one that could interrupt transmission regardless of risk factors and reduce the global disease burden at scale.^4,5

In addition to a single vaccine candidate, the Scripps team noted that the stabilized E1E2 proteins also provide a reproducible template for the development of antibody-based therapeutics, opening potential new avenues in HCV treatment research.^1,7

What Comes Next

The current study data demonstrate proof of concept in animal models. Future work will focus on refining the vaccine candidates to enhance the strength and breadth of immune responses, as well as evaluating protection in more rigorous preclinical studies.^1,7

HCV vaccine development has historically lagged in part due to limited economic incentives and the complexity of producing stable antigens. The ability to reliably manufacture the E1E2 heterodimer in its native form may lower a key barrier to broader research investment and eventual clinical translation. While a licensed HCV vaccine remains years away, the structural engineering advances described in this study represent a meaningful step forward.⁵

REFERENCES

1. He L, Lee YZ, Zhang YN, et al. Native-like soluble E1E2 glycoprotein heterodimers on self-assembling protein nanoparticles for hepatitis C virus vaccine design. Nat Commun. Published online February 11, 2026. doi:10.1038/s41467-026-69418-9

2. World Health Organization. Global Hepatitis Report 2024: Action for Access in Low- and Middle-Income Countries. WHO; 2024. Accessed March 11, 2026. https://www.who.int/publications/i/item/9789240091672

3. Garbuglia A, Pauciullo S, Zulian V, Del Porto P. Update on hepatitis C vaccine: results and challenges. Viruses. 2024;16(8):1337. doi:10.3390/v16081337

4. Cox AL. Challenges and promise of a hepatitis C virus vaccine. Cold Spring Harb Perspect Med. 2020;10(2):a036947. doi:10.1101/cshperspect.a036947

5. Bailey JR, Barnes E, Cox AL. Approaches, progress, and challenges to hepatitis C vaccine development. Gastroenterology. 2019;156(2):418-430. doi:10.1053/j.gastro.2018.08.060

6. Cox AL, El-Sayed M, Kao JH, et al. Progress towards elimination goals for viral hepatitis. Nat Rev Gastroenterol Hepatol. 2020;17(9):533-542. doi:10.1038/s41575-020-0332-6

7. Nanoparticle vaccine approach takes on a new target: hepatitis C virus. News release. Scripps Research Institute. March 3, 2026. Accessed March 11, 2026. https://www.eurekalert.org/news-releases/1118626