Information gained from studies done on both the immune response and vaccine development to related betacoronaviruses can help us gain insight on the immunopathology of SARS-CoV-2 and guide the devlopment of a vaccine. 

Vaccine Development for SARS-CoV-2 Based on Knowledge Gained from SARS-CoV and MERS-CoV

Protein-Based Vaccines in Clinical Trials for COVID-19

Nanomaterials have emerged as promising tools to amplify or suppress host's immune response. By acting as adjuvants added to vaccines for COVID-19, engineered nanomaterials can aid subjects with impaired immune system, such as the elderly, and reduce the amount of vaccine protein production and injection. 


Intranasal delivery of polymer-encapsulated antigen triggers a strong immune response, and the success of vaccination depends on the appropriate type of polymer in combination with the antigen. Similarly, researchers have developed lipid and lipid-based NPs as delivery platforms for mRNAs or siRNAs to enable the synthesis of key viral proteins for vaccination (for example, Moderna’s mRNA-1273/NCT04283461 vaccine) or to inactivate critical viral target genes, respectively. 


Considering the possibility of random viral mutations that may alter the antigen shape, functionalizing nanomaterials with a wide number of molecules at the same time to target the virus, or motifs that are specific for pathogens, will increase the efficiency of vaccines and their ability to prevent viral infection.


There are ongoing screenings and classifications of various nanomaterials based on their immunomodulatory properties and cytotoxicity levels. Developing an adjuvant for clinical use requires Phase III randomized trials, which could take several years.


Nanomaterial-based Immune Modulation for SARS-CoV-2

These are two methods of processing and presenting antigens to human body.

Nanocarriers need to be degraded for encapsulated antigens to trigger cellular immune response, while the surface displayed antigens primarily lead to humoral immune response. 

encapsulated antigen vs surface displayed antigens

- La Jolla Institute for Immunology (LJI) 
- University of Cambridge/DIOSynVax
- Immunonomic Therapeutics/EpiVax/PharmaJet

current studies identifying epitopes

Protein-based vaccines inject coronavirus proteins directly into the body to stimulate an immune response. Alternatively, fragments of proteins or protein shells that mimic the coronavirus' outer coat is also being tested. 

Smith College

Carnegie Mellon University

Subunit vaccines use only the essential antigen or other purified protein subunits of the pathogen via a harmless vector that can best stimulate the immune system. The chance of developing an adverse reaction is significantly lower than in other vaccine types and they elicit a strong immune response. However, they often require adjuvants to stimulate an adequate response and it is difficult to identify the precise antigens that induce long-term immunity.

Subunit Vaccine

Callaway, E. (2020). The race for coronavirus vaccines: A graphical guide. Nature, 580(7805), 576-577. doi:10.1038/d41586-020-01221-y

https://www.nature.com/articles/d41586-020-01221-y

Learn Before

Related

Learn After