A New Determinant, Defined by PLT, Coded for in the HLA Region and Apparently Independent of the HLA‐D and DR Loci

Abstract
A PLT cell was raised between a responder cell which carried the HLA‐D and DR specificities Dw3, 8; DRw3, 8 and a stimulator cell which was most likely homozygous for HLA‐Dw3, DRw3. The PLT cell appeared to recognize a determinant (PL3A) which was (1) different from the officially recognized HLA‐D and DR determinants, (2) was associated with HLA‐Al, B8, Dw3 and DRw3, and (3) segregated in three informative families with HLA. Another responder‐stimulator combination could be selected to raise PLT cells which recognized the same determinant.