ERVW-1 and infection: To put these Env-EL9 variants arising in HLA-B*14-expressing individuals into the context of variation within this epitope overall, the frequency of Env-EL9 variants in B- and C-clade infection in all subjects (https://www.hiv.lanl.gov) is 50% and 34%, respectively, the most frequent variants being K558R (29% and 9% in B- and C-clade sequences, respectively) and K588Q (8% and 16%, respectively).