Stability of DNA/anti-DNA complexes. III. Kinetic control of immune complex size.

The Farr assay and sucrose gradient ultracentrifugation were used to study the importance of kinetic factors on the size of antibody/DNA immune complexes prepared from SLE sera and dsDNA. We have found that significantly different numbers and sizes of antibody/DNA immune complexes can be formed by varying the time course of addition of a given amount of DNA to an SLE serum. For example, the introduction of additional DNA to a preincubated antibody-DNA system does not lead to reequilibration of that system with respect to the amount of DNA bound or the size of the complexes formed even after 1 hr at 37 degrees C. The potential implications of these observations with respect to the pathogenesis of SLE is discussed.