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. 2001 Nov 20;98(24):13826–13831. doi: 10.1073/pnas.241510698

Figure 4.

Figure 4

Flow cytometric analysis of scFv binding to apoptotic cells. (A) Staurosporine-treated Jurkat cells were gated according to forward and side scatter to exclude cell fragments and debris. (B) Cells were gated further into annexin V-positive and -negative populations. (C) Both annexin V-positive and -negative cells were analyzed to determine the extent of scFv binding and PI staining. Annexin V-positive cells (Left) are bound by D56R/S76R and R53G/I57T/D65G (germline), although some annexin V-positive cells fail to bind scFv. Two populations of scFv-bound cells can be distinguished based on PI staining. The mean fluorescence intensity was 1,583 for D56R/S76R, 246 for R53G/I57T/D65G, and 10 for 4VH/1VL. Minimal reactivity was observed with cells incubated with the 4VH/1VL control scFv or with the secondary reagent alone, demonstrating that D56R/S76R and R53G/I57T/D65G are specific for apoptotic cells. No binding to annexin V-negative cells was detected (Right).