PROS1 and COVID-19: Summing up, we have demonstrated that mAbs #11/9 were able to detect RBD fragment in ELISA experiment; the full-length denatured S protein in WB; the full-length native S protein on a cell surface; the full-length S protein in the lung tissues from the COVID19 patients; and, finally, it can neutralize SARS-CoV2 particles in vitro.