TABLE 1.
Comparison of copies of known P. falciparum host receptors per unit surface area on peripheral erythrocytes and cultured erythrocytesa
| Protein (reference[s]) | No. of copies/μm on erythrocyte type: |
||||
|---|---|---|---|---|---|
| pRBC | pLKO | GPA KD | GPB KD | GPC KD | |
| GPA (48, 50, 52) | 7.49 × 103 | 4.42 × 103 | 1.25 × 103 | 1.62 × 103 | 2.38 × 103 |
| GPB (48, 50, 52) | 1.87 × 103 | 1.11 × 103 | 3.11 × 102 | 4.05 × 102 | 5.95 × 102 |
| GPC (48, 50, 51) | 7.49 × 102 | 2.57 × 102 | 1.52 × 102 | 1.62 × 102 | 9.51 × 101 |
| BSG (47, 50) | 2.25 × 101 | 6.26 × 101 | 8.72 × 101 | 2.21 × 101 | 6.52 × 101 |
| CR1 (50) | (1.50–8.98) × 100 | (0.31–1.84) × 100 | (0.41–2.43) × 100 | (0.38–2.31) × 100 | (0.52–3.13) × 100 |
| Band 3 (47) | 7.49 × 103 | 3.53 × 103 | 4.68 × 103 | 1.97 × 103 | 3.26 × 103 |
| Kx (47) | 7.49 × 100 | 8.81 × 100 | 1.05 × 101 | 7.04 × 100 | 8.36 × 100 |
| CD55 (47) | 1.50 × 102 | 1.59 × 102 | 1.49 × 102 | 9.47 × 101 | 1.42 × 102 |
| CD44 (46, 47) | 2.62 × 101 | 4.47 × 101 | 6.66 × 101 | 3.05 × 101 | 3.64 × 101 |
The reported numbers of copies of known P. falciparum host receptors on peripheral erythrocytes (pRBCs) were used to estimate the numbers of copies of host receptors on pLKO cRBCs based on the normalized signal/noise ratios from quantitative surface proteomics and the following reported surface areas for mature RBCs of 133.6 ± 3.0 μm2 and for reticulocytes of 142.4 ± 2.0 μm2 (45), which we assume to be representative of pLKO cRBCs. Since GPA and GPB peptides are indistinguishable by surface proteomics, estimation was based on the reported relative abundance of GPA and GPB on pRBCs. The densities of host receptors per unit surface area for GPA, GPB, and GPC are within 3-fold lower on pLKO cRBCs than on pRBCs.