iBio’s patented lichenase booster molecule (LickM) is a modified thermostable variant of the lichenase protein from the thermophilic bacterium Clostridium thermocellum. LicKM may be effective in addressing issues with subunit vaccines which have a track record in protecting humans against deadly diseases but are often insufficiently stable and typically require the use of a strong adjuvant to boost their immunogenicity.

  • iBio’s patented LicKM protein fusions have been shown to be more soluble and expressed at higher levels than antigens alone.1
  • LicKM is a thermostable protein that can confer its thermostability on fusion proteins, allowing for easy and cost-effective recovery of target proteins following heat treatment.2
  • With three available insertion sites (N-terminus, C-terminus, and internal loop), LicKM allows the integration of three antigens (or multiple copies of the same antigen) within a single stable fusion protein as well as identification of the optimal insertion location.3


  • Increased Solubility
  • Increased Expression
  • Ease of Purification
  • Demonstrated effectiveness
  • Multiple antigen cloning sites
  • Robust immune response
  • Long-lasting immunity


Studies have shown that iBio’s LicKM functions both as a carrier of immunogenic epitopes for presentation to antigen-presenting cells during vaccination and as an adjuvant enhancing immunity. LicKM fusion proteins have been shown to strengthen the initial quantitative immune response to the antigen and to increase the duration of the immune response compared with the antigen alone.


  • Previously published peer-reviewed laboratory data demonstrated an iBio lichenase-based vaccine provided full-protection against aerosolized pneumonic plague in non-human primates.
  • Published data have demonstrated the value of the lichenase technology in vaccine candidates targeting both anthrax and yellow fever virus.

iBio is currently incorporating LicKM in its COVID-19 vaccine candidate IBIO-201. Fusing the SARS-CoV-2 spike protein antigens with iBio’s LicKM technology may be advantageous in achieving a robust and prolonged immune response against COVID-19, potentially reducing the challenges associated with adjuvants and stability associated with subunit vaccines.


  1. Massa al.. (2007) Anti-cancer activity of plant-produced HPV16 E7 vaccine. Vaccine25, 3018-3021
  2. Piruzian E.S., et al. (1998) The use of a thermostable β-glucanase gene from Clostridium thermocellum as a reporter gene in plants.  Gen. Genet., 257: 561-567
  3. Tottey S., et al. (2018) Plant-Produced Subunit Vaccine Candidates against Yellow Fever Induce Virus Neutralizing Antibodies and Confer Protection against Viral Challenge in Animal Models.  J. Trop. Med. Hyg. 98, p. 420–431