Variations in phagocytic particle surface area do not affect uptake efficiency. (A and E) The effects of varying small particle surface area upon uptake efficiency were quantified after coincubating cells with small and large particles. (A–H) Control (shScr) and Cdc42 (shCdc42)-depleted COS1 cells were challenged with a fixed MOI and 4.5-µm beads simultaneously, with 1.5-µm beads at low (A–D) or high (E–H) multiplicity, and uptake by the same cell of the two differently sized particles was quantified microscopically on a per-cell basis. The total number of small (C and G) and large (D and H) beads associated with each cell was used to determine multiplicity empirically. In the low multiplicity scenario (A–D), the large/small surface area ratio was ∼5, and in the high multiplicity scenario (E–H), the large/small surface area ratio was ∼1.3. Error bars represent SEM. ***, P < 0.001.