a, b, Reactivity of 21 different pools of human normal immunoglobulin (HNIG) preparations (27 different vials) to mRBD and mSpike of SARS-CoV-2. MAb CR3022 was used as positive control, three different irrelevant human mAbs were used as negative control. c, d shows reactivity of historic samples from 50 HIV + individuals to mRBD and mSpike of SARS-CoV-2. Both HNIG and serum samples from HIV + donors were collected before the SARS-CoV-2 pandemic. Experiments were performed once. MAb CR3022 was used as positive control at a starting concentration of 100 ug/ml. Of note, the experiments in A and C as well as B and D were done at the same time and their positive controls are shared and displayed in both panels. Experiments were performed once.