Original article Biomed & Pharmacother 1996;50:158-162 © Elsevier, Paris Purine ribonucleotide content in infected HIV-RT ÷ and HIV-RT- lymphoblastoid cell lines F Carlucci, A Tabucchi, F Rosi, R Pagani, R Leoncini, M Pizzichini, E Marinello* Institute of Biochemistry and Enzymology, University of Siena, Pian dei Mantellini 44, 53100 Sienna, Italy Summary - We have studied the purine nucleotide metabolism in the following cell lines: a), H9 (continuous human T-cell line) and H9/HTLV-III (H9 cell line, infected with RT ÷ HIV-I virus); b), A3.01 (human lymphoblastoid cell line CD4 +) and 8E51 (line A3.01 permanently transfected with RT-HIV-I virus). Purine metabolism was studied by evaluating the content of the most important ribonucleotides (AMP-GMP-IMP-NAD-ADP-GDP-ATP-GTP) and their ratios. We determined several differences between the cell lines before and after viral infection. All nucleotides except triphosphates were reduced in Hg/HTLV-III with respect to H9 cells; in 8E51, however, triphosphates were markedly reduced, while monophosphates increased with respect to A3.01 uninfected cells. Also the ratios exhibited different behaviors, for example the total adenine nucleotides total guanine nucleotides ratio (ZA/ZG) was enhanced in H9/HTLV-III cells with respect to H9 and unaltered in 8E51 with respect to A3.01 cells. We may conclude that the HIV-1 virus strongly influences the purine nucleotide metabolism of the host cells and that the changes are different when induced either by RT* or RT virus. - HIV-1 / cell cultures / purine nucleotides INTRODUCTION Purine nucleotides play an essential role in cellu- lar metabolism since they participate in the bio- chemical reactions which are responsible for the energetic state of the cell, and are important co- factors in major cellular macromolecular biosyn- theses. As a direct consequence of HIV-1 infection, the viral replication should involve variations in purine nucleotide metabolism in the host cells. These changes should affect the intracellular nu- cleotide content and the incorporation of labelled precursors, such as ~4C-formate into purines. The analysis of nucleotide content is a well- known approach to the study of purine nucleotide metabolism. Levels of the most important nu- cleotides (NAD, AMP, IMP, GMP, ADP, ATP, GDP, GTP) have already been described in nor- mal human lymphocytes [1, 13, 14, 19], together with the associated parameters: 1), the energy charge (EC) of adenylate and guanylate, indices of cell energy, viability and metabolic state; 2), (AMP + ADP)/ATP and (GMP + GDP)/GTP ratios, which indicate a shift of adenylates or guanylates towards ATP or GTP synthesis; 3), the total adenine nucleotides total guanine nucleotides (ZA/ZG) ratio, which repre- sents the preferential channelling of IMP towards adenylate or guanylate synthesis [17] and is in- versely related to cell proliferation [13]. The difficulty of analyzing nucleotide content and the related parameters in lynaphocytes from AIDS patients due to lymphopenia has limited the studies in this field [15, 16, 18, 25]. In previous studies we investigated the behavior of purine metabolism in lymphoblastoid cell lines infected with HIV-1 virus (H9/HTLV-III) with re- spect to its control (H9), pointing out important variations [26]. We demonstrated that purine nu- cleotide content was reduced in infected cells with the exception of triphosphates. Evaluation of * Correspondence and reprints.