Fig. 2

PD-1 receptor occupancy by prolgolimab, nivolumab and pembrolizumab before and after 24-h resting. PBMCs were preincubated with prolgolimab, nivolumab and pembrolizumab, then unbound antibodies were washed off. One portion of the cells was stained with the antibody panel immediately (0h), while the remaining portion was stained after 24 h of the incubation (24 h) in the culture medium. The proportion of T-lymphocytes (CD45⁺/CD3⁺) stained with anti-PD-1 antibody (clone PD1.3.1.3) was normalized to the sample without the addition of therapeutic anti-PD-1 antibodies (prolgolimab, nivolumab and pembrolizumab). Data is shown mean ± SD of results with 3 donors. Statistical analyses were performed on samples after 24 h resting using the two-tailed paired Student’s t-tests.