THE CYTOTOXIC HLA-DQ3 REACTIVE HUMAN HYBRIDOMA ANTIBODY-4166 THAT MAYDISTINGUISH DQ7+8 FROM DQ9

The human cytotoxic hybridoma antibody 4166 (IgM[x]) was generated by fusing an in vitro EBV-transformed B-LCL from a multiparous woman with the mouse-human heteromyeloma fusion partner CB-F7. In microcytotoxic ity and IIF tests with B-LCLs as target cells, the mAb 4166 was specif ic for DQ3 (= DQ7+8+9). However, when used for DQ typing of class-II-p ositive PBMCs, 4166 could be rendered functionally specific for DQ7+8 and did not react with DQ9(+) PBMCs. Binding of mAb 4166 to DQ8-positi ve cells was efficiently blocked by several allotype-specific mAbs rec ognizing DQ8. Other HLA class-II-specific mAbs were unable to inhibit. With the use of mAb 4166, it is possible to discriminate DQ7+8 from D Q9 in serologic DQ typing.