The size of rosettes is determined by multiple serum components
| Serum Fraction . | Whole Serum . | conA Affinity (C) . | Anion Exchange (A) . | S-200 Gel Filtration (S) . | IgM Affinity (M) . | Fractions + IgM (M2) . | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| C1 . | C2 . | C1 + C2 . | A1 . | GF4 . | A1 + GF4 . | S1 . | S2 . | S3 . | S1 + S2 . | S1 + S3 . | S2 + S3 . | S1 + S2 + S3 . | M1 . | M1 + M2 . | C1 + M2 . | A1 + M2 . | S2 + S3 + M2 . | ||
| Average rosette size | 4.3 | 2.7 | 2.3 | 4.3 | 2.6 | 2.3 | 4.4 | 2.2 | 2.8 | 2.4 | 3.0 | 2.8 | 2.7 | 4.0 | 2.7 | 3.9 | 2.8 | 4.2 | 2.8 |
| + | + | + | + | + | + | + | + | + | + | + | + | + | |||||||
| Serum Fraction . | Whole Serum . | conA Affinity (C) . | Anion Exchange (A) . | S-200 Gel Filtration (S) . | IgM Affinity (M) . | Fractions + IgM (M2) . | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| C1 . | C2 . | C1 + C2 . | A1 . | GF4 . | A1 + GF4 . | S1 . | S2 . | S3 . | S1 + S2 . | S1 + S3 . | S2 + S3 . | S1 + S2 + S3 . | M1 . | M1 + M2 . | C1 + M2 . | A1 + M2 . | S2 + S3 + M2 . | ||
| Average rosette size | 4.3 | 2.7 | 2.3 | 4.3 | 2.6 | 2.3 | 4.4 | 2.2 | 2.8 | 2.4 | 3.0 | 2.8 | 2.7 | 4.0 | 2.7 | 3.9 | 2.8 | 4.2 | 2.8 |
| + | + | + | + | + | + | + | + | + | + | + | + | + | |||||||
Average size of rosettes formed in the presence of the various fractions and combinations of fractions from the conA–Sepharose affinity (each at 10% vol/vol), Sepharose Q anion exchange (A1 at 15% vol/vol; GF at 10% vol/vol), S-200 gel filtration (each at 15% vol/vol), and IgM affinity (each at 15% vol/vol) columns. The rosetting assay was conducted as described in the legend to Figure 1, and the number of uninfected RBC in each of at least 100 rosettes was counted per sample. + denotes significant difference compared with the size of rosettes formed in whole serum (P = .05). C1, conA-unbound fraction; C2, conA-bound fraction; A1, anion exchange-unbound fraction; GF4, anion exchange-bound gradient fraction 4; S1, S-200 higher molecular mass fraction; S2, S-200 intermediate molecular mass fraction; S3, S-200 lower molecular mass fraction; M1, IgM affinity-unbound fraction; M2, IgM affinity-bound fraction (ie, IgM).