Determination of sensitivity of detection of KSHV sequences. Lane 1, 100-bp DNA ladder; lane 2, K562 cell line DNA; lane 3, HL-60 cell line DNA; lane 4, distilled water. Lanes 2 through 4 served as a negative controls. Lane 5, 10 ng of KS-1 cell line DNA which is estimated to contain 24,000 copies of KSHV sequences. Lanes 5 through 9 are serial 10-fold dilutions of KS-1 cell line DNA in K562 cell line DNA. The 160-bp band that represents the nest-primer product detected up to 2.4 copies of KSHV sequences.