Pathogenicity and effector functions of 34-3C Ig class-switch variants*
| Class . | Pathogenicity* . | C′† . | FcR‡ . | Pathogenesis . |
|---|---|---|---|---|
| pIgM§ | 25 μg | ++ | − | Hemagglutination |
| mIgM§ | — | − | − | — |
| pIgA§ | 25 μg | − | − | Hemagglutination |
| mIgA§ | — | − | − | — |
| IgG1 | 500 μg | − | + | Erythrophagocytosis |
| IgG2a | 25 μg | ++ | ++ | Erythrophagocytosis |
| IgG2b | 25 μg | ++ | ++ | Erythrophagocytosis |
| IgG3 | 100 μg | + | − | Erythrophagocytosis |
| Class . | Pathogenicity* . | C′† . | FcR‡ . | Pathogenesis . |
|---|---|---|---|---|
| pIgM§ | 25 μg | ++ | − | Hemagglutination |
| mIgM§ | — | − | − | — |
| pIgA§ | 25 μg | − | − | Hemagglutination |
| mIgA§ | — | − | − | — |
| IgG1 | 500 μg | − | + | Erythrophagocytosis |
| IgG2a | 25 μg | ++ | ++ | Erythrophagocytosis |
| IgG2b | 25 μg | ++ | ++ | Erythrophagocytosis |
| IgG3 | 100 μg | + | − | Erythrophagocytosis |
The quantity of mAb required for inducing anemia (defined as Ht values <40%) in BALB/c mice based on the results obtained in previous8 and the present studies.
The capacity of each Ig isotype to activate complement was judged by the extent of C3 deposition on circulating RBC in vivo based on the results obtained in previous8 and the present studies.
FcR involved in phagocytosis. Three different activating FcγR (FcγRI, FcγRIII, and FcγRIV) expressed on murine phagocytes display different specificities to IgG subclasses: FcγRI for IgG2a, FcγRIII for IgG1, IgG2a and IgG2b, and FcγRIV for IgG2a and IgG2b.16
pIgM and mIgM: polymeric and monomeric IgM. pIgA and mIgA: polymeric and monomeric IgA.