Figure 3.

TRIM72 regulates CR-mediated phagocytosis in AMs. (A) Representative images of low versus high phagocytic indexes showing primary AMs containing green fluorescent beads (left); representative images showing low and high % phagocytic AMs. Arrows, low phagocytic index AMs; arrowheads, high phagocytic index AMs. (B) Representative flow cytometry detection of phagocytizing cells in no beads control, WT + beads, and TRIM72^KO + beads AMs. Bar defines bead-containing cell population (%) and mean fluorescence intensity (MFI). (C) Statistics of average phagocytic index and % phagocytic AMs in WT and TRIM72^KO AMs; n = 5 for both groups, *P < 0.05. (D) Statistics of flow cytometry MFI and % FITC⁺ cells in WT and TRIM72^KO AMs; n = 3 for both groups, *P < 0.05. (E) Western blot detection of TRIM72 overexpression (T72^OE) after lentivirus L309C infection of murine alveolar macrophage cells (MH-S) with control and TRIM72 containing vectors (left); ACTB was detected as a loading control. Quantification of opsonized sheep red blood cell (sRBC) phagocytosis by MH-S cells (right) in the presence of IgG (Fcγ receptor [FcγR]–mediated phagocytosis) or IgM (CR-mediated phagocytosis); n = 6 for each group, *P < 0.05 and **P < 0.005 compared with WT control. Data are presented as mean (±SE). Con = control; TRIM72^KO = TRIM72 knockout; TRIM72^OE = TRIM72 overexpression.