In vivo aggregation of hFcγRI induces PSA. (A-B) Indicated mice were injected with 200 μg of anti-hFcγRI.1 blocking mAb or anti-hFcγRI.2 nonblocking mAb (A) or with the indicated amounts of anti-hFcγRI.2 nonblocking mAb (B), and central temperatures were monitored (n ≥ 3). The same curve corresponding to 200 μg of anti-hFcγRI.2 nonblocking mAb injected in hFcγRI^tg 5KO mice is represented in experiments shown in panels A and B, which were performed together. Note: anti-hFcγRI.1 mAb is an antagonistic blocking antibody and anti-hFcγRI.2 mAb an agonistic nonblocking antibody. (C-D) 5KO and/or hFcγRI^tg 5KO mice were pretreated with indicated reagents and injected with preformed mouse IC made of mouse polyclonal anti-GPI serum and GPI, and central temperatures were monitored (C, n ≥ 4; D, n ≥ 3). Data are representative of at least 2 independent experiments and are represented as means ± SEM (for panel D, between the untreated and the anti-FcγRIV + anti-hFcγRI.1–treated groups).