4 component system: The MHC II Receptor (MHC2R) Family
| P04439 | HLA class I histocompatibility antigen, A alpha chain |
|---|---|
| P01889 | HLA class I histocompatibility antigen, B alpha chain |
| P10321 | HLA class I histocompatibility antigen, C alpha chain |
| P13747 | HLA class I histocompatibility antigen, alpha chain E |