The protein/DNA complexes in KSHV-positive PELs are primarily comprised of p65/p50 heterodimers and p50 homodimers.

To assess the components of the protein/DNA complexes, nuclear proteins extracted from latent cultures of BC1, BC2, and BC3 cells were incubated with antibodies to p50, p65, and c-rel before the addition of NF-κB–specific radiolabeled oligonucleotide. Compared with control samples in which no antibody was added (lanes 1, 5, and 9) addition of p50 antibody (lanes 2, 6, and 10) resulted in a complete shift of the lower complex and a large proportion of the upper complex in each cell line. Partial shifting of the upper complex was also seen on addition of p65 antibody, but no shifting of either complex was observed after addition of c-rel antibody.