460 Resistance of HIV Infection in Resting Memory CD4+CD62L- T-lymphocytes In Vitro to Drugs Used in HAART Gondois-Rey*, Fernandez, Biancotto, Bettendrofer, Vigne, Hirsch INSERM, Marseille, France
Background: The persistence of HIV in resting memory CD4 T-lymphocytes presents one of the major obstacle in the virus eradication. These cells form a reservoir of HIV that persists in infected individuals in spite of an early application of HAART and a successful control of plasma viremia. We previously demonstrated in ex vivo infected human lymphoid tissue, that the CD62L- subset constitutes the major population of the HIV-infected HLA-DR- resting memory CD4 T-cells. Therefore, we sought to analyze the efficiency of HIV inhibitors commonly used in HAART in this particular cell subset.
Methods: The cell cultures enriched for CD62L-CD4 T-lymphocytes were derived from PBMC of healthy donors after repeated phytohemagglutinin-activation. The IC50 of several nucleosidic (NRTI) and non-nucleosidic (NNRTI) inhibitors of reverse transcriptase (RT) were determined for HIV infection of these cells in a resting and in an activated state. The efficiency of HIV-protease inhibitors (PI) was determined for the virus produced in the presence of drug by the cultures of resting or activated memory T-cells previously exposed to HIV.
Results: The IC50 of NRTI inhibitors were 6- to 8-fold higher in resting memory CD62L-CD4 T-lymphocytes than in activated CD62L+ cells. NNRTI inhibitors were equally efficient in both cells types. The efficiency of PI inhibitors in resting memory CD4 T-lymphocytes was lower or equal in comparison with activated cells.
Conclusions: The efficiency of NRTI and protease inhibitors is linked to activation state of CD4 T-lymphocytes. The higher IC50 observed for HIV inhibitors in resting memory CD62L-CD4 T-cells than in activated CD62L+ T-cells might be related to generally lower levels of metabolism in resting cells. The relative resistance of resting memory CD62L-CD4 T-lymphocytes to NRTI and PI inhibitors in vitro is compatible with a residual replication and a continuous spread of the virus in the reservoir of HIV infection during suppressive HAART. Our cell culture system represents a useful model for testing inhibitors efficient in resting memory CD4 T-lymphocytes.
