[Expression of class II HLA antigens on cryopreserved isolated mononuclear splenic cells]

The human spleen presents a rich source of class 2 HLA-positive mononuclear cells. After cryopreservation in liquid nitrogen and storage during 18 months these cells retain high viability and continue expressing class 2 HLA antigens on their membrane. Cryopreserved cells react specifically with antibodies to particular determinants of class 2 HLA-DR molecules. This permits their using as target-cells in serological reactions, and serves the basis for creation of banks of well-characterized "standard" class 2 HLA-positive cells with the known phenotype.