The Tyrosine-Containing Sequence Within the FcγRIIB Cytoplasmic Domain Is Required for the Inhibition of Phagocytosis by the Chimeric Receptor I-IIA-IIA
| . | PI . | MFI . | |
|---|---|---|---|
| α-FcγRI . | α-FcγRII . | ||
| Experiment 1 | |||
| I-IIA-IIA | 68 | 85 | — |
| I-IIA-IIA + B2 | 25 | 75 | 64 |
| I-IIA-IIA + B2-YF | 55 | 79 | 61 |
| I-IIA-IIA + B2ΔYSLL | 59 | 88 | 66 |
| Experiment 2 | |||
| I-IIA-IIA | 127 | 290 | — |
| I-IIA-IIA + B2 | 76 | 214 | 65 |
| I-IIA-IIA + B2-YF | 138 | 240 | 80 |
| I-IIA-IIA + B2ΔYSLL | 138 | 308 | 84 |
| Experiment 3 | |||
| I-IIA-IIA | 91 | 302 | — |
| I-IIA-IIA + B2 | 41 | 223 | -150 |
| I-IIA-IIA + B2-YF | 65 | 240 | -150 |
| I-IIA-IIA + B2ΔYSLL | 77 | 309 | -150 |
| Experiment 4 | |||
| I-IIA-IIA | 169 | 297 | — |
| I-IIA-IIA + B2 | 80 | 270 | 326 |
| I-IIA-IIA + B2-YF | 207 | 275 | 283 |
| I-IIA-IIA + B2ΔYSLL | 199 | 259 | 290 |
| . | PI . | MFI . | |
|---|---|---|---|
| α-FcγRI . | α-FcγRII . | ||
| Experiment 1 | |||
| I-IIA-IIA | 68 | 85 | — |
| I-IIA-IIA + B2 | 25 | 75 | 64 |
| I-IIA-IIA + B2-YF | 55 | 79 | 61 |
| I-IIA-IIA + B2ΔYSLL | 59 | 88 | 66 |
| Experiment 2 | |||
| I-IIA-IIA | 127 | 290 | — |
| I-IIA-IIA + B2 | 76 | 214 | 65 |
| I-IIA-IIA + B2-YF | 138 | 240 | 80 |
| I-IIA-IIA + B2ΔYSLL | 138 | 308 | 84 |
| Experiment 3 | |||
| I-IIA-IIA | 91 | 302 | — |
| I-IIA-IIA + B2 | 41 | 223 | -150 |
| I-IIA-IIA + B2-YF | 65 | 240 | -150 |
| I-IIA-IIA + B2ΔYSLL | 77 | 309 | -150 |
| Experiment 4 | |||
| I-IIA-IIA | 169 | 297 | — |
| I-IIA-IIA + B2 | 80 | 270 | 326 |
| I-IIA-IIA + B2-YF | 207 | 275 | 283 |
| I-IIA-IIA + B2ΔYSLL | 199 | 259 | 290 |
Four representative experiments are shown. The PI of I-IIA-IIA–mediated phagocytosis was determined in the absence or presence of FcγRIIB2 or its mutants. Within each experiment, expression of WT FcγRIIB and mutant FcγRIIB was similar and FcγRIIB mutants did not reduce the expression of I-IIA-IIA. B2, FcγRIIB2; B2-YF, FcγRIIB2 in which the tyrosine in the YSLL cytoplasmic region has been changed to phenylalanine; B2ΔYSLL, FcγRIIB2 in which the cytoplasmic YSLL sequence has been deleted. Different preparations of MoAbs were used in experiment 1 (anti-FcγRI) and experiment 4 (anti-FcγRII). α-FcγRI, anti-FcγRI (recognizes I-IIA-IIA); α-FcγRII, anti-FcγRII (recognizes FcγRIIB).
Not done.