The efficiency of bridging sheet recruitment determines HIV-1 R5 envelope sensitivity to soluble CD4 and macrophage tropism by O'Connell O, Repik A, Reeves JD, Gonzalez-Perez MP, Quitadamo B, Duenas-Decamp M, Peters P, Lin R, Anton ED, Zolla-Pazner S, Corti D, Wallace A, Wang S, Kong X, Lu S, Clapham PR