CD1D and plasma cell myeloma: Since CD1d tetramers are widely used for studying iNKT cells, we went on to compare loading properties of rat CD1d dimers derived from our own production in mouse myeloma cells and rat CD1d tetramers provided by the NIH tetramer core facility produced from CD1d monomers in human embryonic kidney derived 293T cells and with rat β2-microglobulin (Fig 4).