Figure 1.

Anti-PGT121 antibodies develop in pigtailed macaques following exposure to human antibodies. Five pigtailed macaques were administered PGT121 or a human IgG1 isotype control antibody intravenously (1mg/kg) prior to challenge with cell-free or cell-associated SHIV. Macaques NM04 and NM05 were administered human seminal plasma either intrarectally or both intravaginally and intrarectally prior to intrarectal challenge with SHIV. Viraemic animals were then infused with PGT121 with either WT or LALA Fc. Macaque anti-PGT121 ADA are shown in the blue line (left y-axis) while SHIV viral loads are shown in the red line (right y-axis). Black arrows indicate antibody administration while red arrows indicate SHIV challenge. The red text indicates failed therapy with PGT121 WT or LALA.