GrttnC polyantigen expression in HEK293 cells. HEK293 cells were co-transfected for 48 h with the indicated plasmids and pcDNA3.1Zeo/CAT. HIV-1 p24 antigen was quantified in cell lysates as the measure of GrttnC polyantigen content and normalised using CAT expression. Each data point is the mean of 6 replicated transfections ± SD. A: Plasmids expressing GrttnC with and without PCV-1 whole genome or Pcap or PcapR DNA sequence. pTHCap minus insert served as the vector control. B: Plasmids expressing GrttnC and containing Pcap elements from either PCV-1 (pTHPcapgrttnC, pTHCgrttnC and pTHCRgrttnC), PCV-2 (pTHC2grttnC and pTHC2RgrttnC) or BFDV-AFG-ZA (pTHCB3grttnC, pTHCLEgrttnC and pTHCLE3grttnC). * p < 0.01; **p < 0.05.