To gauge whether breadth developed within the window of evaluation, cross-neutralizing activity of a single plasma sample from subject 185F (23-months) and subject 205F (20-months) was measured against heterologous 0-month subtype C Envs from six other subjects in the same cohort (Fig. 2) . Consistent with previous studies of early subtype C infection [15, 16] , Nab in 185F and 205F was mostly strain-specific. However, each of these plasma samples neutralized 2 of the 6 heterologous Envs with an IC50 of greater than 1:100, and in two cases approaching 1:1000. Interestingly, 205F plasma potently neutralized the 185F Env (red dot on right point plot), but the reciprocal was not observed (green dot on left point plot). Thus, Nab in these plasma samples was directed against predominantly strain-specific targets, but were also capable of recognizing some common epitopes by approximately two years after infection.