CD80 and eye disorder: Since the complete deletion of ICP22 increases CD80 and CD8 expression in corneas of infected mice, leading to increased eye disease (15), the current study was designed to define the amino acid region of ICP22 required for binding to the CD80 promoter, generate a recombinant virus lacking these ICP22 amino acids, and determine whether the effect of this truncated virus on HSV-1 infectivity is similar to that of the ICP22-null virus in vitro and in vivo.