Class | Serum concentration (mg ml−1) | Mass (kDa) | Light chains | Heavy chains | Chain structure |
|---|---|---|---|---|---|
IgG | 12 | 150 | κ or λ | γ | κ2γ2 or λ2γ2 |
IgA | 3 | 18 | κ or λ | α | (κ2α2)n or (λ2α2)n |
IgM | 1 | 950 | κ or λ | μ | (κ2μ2)5 or (λ2μ2)5 |
IgD | 0.1 | 175 | κ or λ | δ | κ2δ2 or λ2δ2 |
IgE | 0.001 | 200 | κ or λ | ε | κ2ε2 or λ2ε2 |
Note: n = 1, 2, or 3. IgM and oligomers of IgA also contain J chains that connect immunoglobulin molecules. IgA in secretions has an additional component. | |||||