While viral fusion proteins are highly desirable for subunit vaccine generation, their inherent metastable nature complicates implementation and development.  We have harnessed the structural rigidity that dityrosine bonding imparts as a means of surmounting these difficulties.  Dityrosine bonds are naturally occurring and are formed through multiple reaction mechanisms including photo-activation, chemical, and enzymatic catalyzation.  While most in vitro reaction mechanisms are too harsh for the maintenance of protein conformation, we have modulated the enzymatic reaction in order to target crosslinks to specific regions of fully-folded protein immunogens in order to maintain potently neutralizing conformational epitopes or preserve conformational integrity in otherwise unstable molecules.    By focusing Ab responses toward desired epitopes, dityrosine-stabilized immunogens elicit focused and more potently neutralizing Ab responses, and thus improve their performance as vaccine immunogens.

Learning Objectives:
1. Describe the inherent stability issues for viral fusion proteins that make them difficult to use as subunit vaccines

2. Describe the characteristics of dityrosine crosslinking in terms of bond length, length of reaction, bond characteristics, and when the bond is introduced

3. Describe the attributes that dityrosine bonding imparts on the RSV F protein

4. Describe the advantage of formulation of DT-preF on AdvaxSM

5. Describe the characteristics of Headless HA that make it well suited as a dityrosine bond substrate.