Unintegrated viral DNA as a marker for human immunodeficiency virus 1 infection in vivo and in vitro

The unintegrated viral DNA found in human immunodeficiency virus (HIV) infection includes linear and circular forms. The circular unintegrated viral DNA (CUVD) could be of either 1-long terminal repeat (LTR) or 2-LTR form. Inverse primers from nef (upstream) and gag (downstream) gene sequences of HIV-1 genome were designed to span the LTR circle junction. CUVD was assayed in unstimulated, quiescent persistently infected cell lines 8E5, HIIIB, and GB8, as well as in peripheral blood lymphocytes (PBLs) of HIV-1-infected patients by nested PCR in a cross sectional study. CUVD in the infected cell lines (in vitro) was predominantly of 2-LTR form in 8E5 and GB8 cells, while in HIIIB cells, there was besides 1-LTR and 2-LTR an additional, intermediate form. In vivo, CUVD was predominantly of 1-LTR form. The possibility of using CUVD, an early phenomenon in the virus replication, as an additional postpenetration, preintegration marker of HIV infection is discussed.