A yeast-based vaccine candidate targeting a conserved influenza protein has protected mice against multiple influenza A strains, raising the possibility of a broader and longer-lasting alternative to conventional seasonal flu vaccines. Developed by researchers at the University of Michigan Engineering, the system uses genetically engineered baker’s yeast to manufacture virus-like particles, or VLPs, displaying the influenza M2 protein. The particles resemble viruses closely enough to stimulate immune recognition, but contain no viral genetic material and cannot cause infection.
The work addresses two persistent problems in influenza prevention: the speed and cost of vaccine production, and the virus’s ability to change its surface proteins. Most seasonal influenza vaccines are produced in chicken eggs, a manufacturing method that has been used for roughly eight decades. Although egg-based production remains effective, it can take months and may not adapt quickly when a newly circulating strain differs substantially from the viruses selected for the vaccine. Egg adaptation can also introduce mutations that alter vaccine antigens. A faster production platform could be particularly valuable when influenza undergoes a major genetic shift and begins spreading through human populations with little pre-existing immunity.
Current influenza vaccines primarily target hemagglutinin, or HA, the protruding surface glycoprotein that enables the virus to attach to and enter host cells. HA is highly immunogenic, meaning it readily provokes antibodies, but it also evolves rapidly through antigenic drift. Small mutations can change the regions recognized by antibodies, weakening protection and forcing health authorities to update vaccine formulations regularly. More dramatic reassortment events, known as antigenic shift, can produce viruses with substantially different HA proteins and create pandemic risks. A vaccine directed at a more stable viral component could retain activity across a wider range of influenza strains and remain effective for longer periods.
The Michigan team instead focused on M2, a much smaller influenza protein that performs an essential role during viral replication. M2 forms a proton channel in the viral envelope, helping regulate acidity as the virus enters a host cell and releases its genetic material. It also contributes to the assembly and release of newly formed virions. Unlike HA, the external portion of M2 is relatively conserved among many influenza A viruses. The researchers report that M2 has changed far less than HA over time and retains substantial sequence similarity across human, swine and avian influenza A strains. That conservation makes it an attractive target for a vaccine intended to provide heterosubtypic protection—immunity against several influenza subtypes rather than only a closely matched strain.
M2 has not traditionally been the leading vaccine target because it generally produces a weaker antibody response than HA. The researchers sought to overcome that limitation by presenting large amounts of M2 on the surface of VLPs. These structures imitate key physical characteristics of viruses, including their size and repetitive surface organization, which can improve antigen uptake and presentation by immune cells. However, VLPs are not complete viruses: they lack the genome required for replication. In principle, this combination offers the immunological advantages of virus-like architecture without the risks associated with live or replication-competent vaccine platforms.
To produce the particles, graduate researcher Trang Hoang modified the genome of Saccharomyces cerevisiae, the species commonly used in baker’s yeast, so that the cells would manufacture high levels of influenza M2. The engineered yeast was grown in a nutrient-rich liquid culture, creating a potentially scalable biological production system based on inexpensive and familiar fermentation technology. Hoang then used mild chemical treatment to remove the yeast’s rigid cell wall while preserving the plasma membrane. This step allowed M2-containing membrane material to bud outward and form virus-like particles. Centrifugation and purification procedures were subsequently used to separate the M2 VLPs from the yeast-derived material.
In preliminary animal experiments, the purified particles generated a strong M2-specific immune response. Eighteen mice received the vaccine, and serum samples collected afterward contained abundant antibodies that recognized M2 from five influenza strains. The researchers then challenged vaccinated animals with three different influenza strains. They observed complete protection from infection in the tested mice, an encouraging result suggesting that the vaccine can stimulate immunity that extends beyond a single viral subtype. The findings also indicate that displaying M2 in a VLP format may compensate for the protein’s relatively modest immunogenicity when presented alone.
The results remain an early proof of concept rather than evidence that annual influenza vaccination can be abandoned. Mouse immune systems do not fully reproduce the complexity of human influenza infection, and protection against infection in an experimental challenge does not automatically predict protection against severe disease in people. The researchers still need to determine how long the M2-induced immune response persists, whether the vaccine protects against a broader collection of influenza viruses, and which immune mechanisms are most important. Antibodies against M2 may limit viral spread, while T-cell responses could help recognize and eliminate infected cells; understanding the balance between these defenses will be important for optimizing the formulation. The team also plans to investigate vaccine designs for individuals whose immune systems respond weakly to vaccination.
The manufacturing platform could eventually expand beyond injectable vaccines. The technology has been licensed to a company developing yeast-based systems for oral vaccines, and the researchers envision engineered yeast strains that might one day be produced through fermentation and formulated for administration by mouth. Such a strategy would require extensive testing to establish dose control, stability, absorption and safety, but it illustrates the broader potential of yeast as a vaccine-production host. For now, the University of Michigan study provides a promising demonstration that a conserved influenza protein can be combined with yeast-derived VLP technology to produce a candidate vaccine rapidly and at potentially lower cost. The team will present the findings at the American Chemical Society’s Fall 2026 meeting in Chicago, where the work is expected to contribute to ongoing efforts to develop influenza vaccines capable of meeting both seasonal and pandemic threats.
Subject of Research: Yeast-derived virus-like particle vaccine targeting the conserved influenza A M2 protein
Article Title: Toward an affordable universal influenza vaccine: M2-based Virus-like Particles
News Publication Date: August 24, 2026
Web References: https://acs.digitellinc.com/live/37/session/593122; https://www.acs.org/events/fall.html; https://youtube.com/shorts/zEpgeHQpTOA
References: Research presented at ACS Fall 2026 by Trang Hoang and Fei Wen, University of Michigan Engineering
Image Credits: Fei Wen
Keywords: influenza vaccine, universal flu vaccine, M2 protein, virus-like particles, VLPs, baker’s yeast, Saccharomyces cerevisiae, vaccine development, influenza A, viral immunology, infectious diseases, fermentation technology
Tags: Addressing influenza virus surface protein mutationBroad-spectrum influenza protectionGenetically engineered baker’s yeast for vaccine productionInfluenza M2 protein as vaccine targetInfluenza vaccine development using synthetic biologyLong-lasting influenza immunityOvercoming limitations of egg-based vaccine productionPotential replacement for seasonal flu shotsRapid and cost-effective vaccine manufacturingVirus-like particles (VLPs) in flu vaccinesYeast-based universal flu vaccine
