Molecular heterogeneity of human lymphoid (HL-A) alloantigens.

Soluble preparations of HL-A alloantigens were separated by gel filtration into components having either the "LA" series or the "4" series of alloantigenic determinants. This separation may indicate that several different structural cistrons within the HL-A (locus) control the expression of these two series of determinants. The alternative possibility, in which one structural cistron with multiple mutational sites controls the synthesis of a single molecule cannot be excluded.