Interactions between rheumatoid factor and native gamma-G-globulins studied in the ultracentrifuge.

Interactions between a rheumatoid factor preparation and native human (normal and myeloma) and animal γG-globulins have been studied in the ultracentrifuge. Using pooled normal γG-globulin or a myeloma γG-globulin, the extent of reaction has been shown to be dependent upon the reactant concentration employed, a four-fold excess, by weight, of γG-globulin over rheumatoid factor being required to ensure maximum production of 22S complex. All native myeloma γG-globulins tested reacted to give a 22S complex, the majority showing similar reactivity to the normal γG-globulin control. A small proportion, however, showed significantly different reactivities. Of the animal γG-globulins tested, only rhesus monkey γG-globulin showed reactivity similar to human γG-globulin. The other species showed decreased reactivity. The importance of these findings is discussed.