A protein-based SARS-CoV-2 vaccine (IMAGE) Boston Children's Hospital Caption Shown at far left, the vaccine consists of a portion of the spike protein’s receptor-binding domain (RBD), shown in dark blue, attached to a single domain antibody-fragment that recognizes class II major histocompatibility complex (MHC) proteins, shown as orange ovals. These conjugates home to antigen-presenting cells (APCs), which then process and display the RBD to T and B cells. This leads to a robust immune response, eliciting both T cells and high titers of neutralizing antibodies that are protective across SARS-CoV-2 variants. Credit Novalia Pishesha, Boston Children’s Hospital Usage Restrictions Please credit as indicated. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.