Nuclear antigens, as DNA, of DSB389 MAb and some other anti-desmin monoclonal antibodies.

The anti-desmin monoclonal antibodies (MAbs) DSB389, AC54, and DSB860 recognize intermediate filaments (IFs) and nuclear antigens that appear granular, locate around chromosomes, and are insoluble following 0.5% Triton X-100 and cetyltrimethylammonium bromide (CTAB) extraction. Nuclear antigens of the MAbs were searched for in an IFs-deficient clone of SW13 cells. Reactive materials specific to DSB389, AC54, and DSB860 MAbs were trapped at the top of the gel of SDS-agarose-PAGE. The reactivity of the materials disappeared after treatment with DNase I. The reactivity, or trapping of this material at the top of the gel, required previous heat treatment of the sample before application to the gel. The MAbs recognized both single-stranded and double-stranded DNA in ELISA. These results indicate that at least the main nuclear antigens of DSB389, DSB860 and AC54 MAbs are DNA.