HUMAN IMMUNODEFICIENCY VIRUS TYPE 1 RESISTANCE TO NUCLEOSIDE ANALOGUES AND REPLICATIVE CAPACITY IN PRIMARY HUMAN MACROPHAGES

Unité de Rercherche Antivirale, Inserm U552, Paris F-75018 France; Université Denis Diderot Paris 7, Paris F-75018 France.; Service de Pharmacologie et d'Immunologie DSV/DRM, CEA/Saclay, 91191 Gif sur Yvette cedex, France

^* To whom correspondence should be addressed. Email: clavel{at}bichat.inserm.fr.

	Abstract

Antiretroviral treatment failure is associated with the emergence of resistant HIV-1 populations which often express altered replicative capacity (RC). Resistance and replicative capacity (RC) of clinical HIV-1 strains, however, are generally assayed using activated PBMCs or tumor cell lines. Because of their high proliferation rate and concurrent high dNTP content, both resistance and RC alterations might be misestimated in these cell systems. We have evaluated resistance of HIV-1 clones expressing a variety of RT resistance mutations in primary human macrophages using a single cycle system. Our experiments indicate that d4T, ddI and 3TC are more potent in macrophages than in HeLa-derived P4 tumor cells. Mutant viruses bearing thymidine analogue mutations (TAMs) or the K65R mutation had similar resistance levels in the two cell types. Strikingly, however, the M184V mutant, although fully resistant to 3TC in P4 cells, maintained some susceptibility to 3TC in macrophages from 8 out of 11 donors. Using the same system, the impact of resistance mutations on HIV RC was minimal in activated PBMCs and in P4 cells. By contrast, mutant viruses exhibited strongly impaired RC relative to WT in macrophages, with the following RC order: WT > 2TAMs > 4TAMs = M184V > K65R. In undifferentiated monocytes, WT virus replication could be detected in 3 of 6 donors, but replication of all mutant viruses remained undetectable. Altogether our results confirm that NRTIs are powerful antiviral agents in differentiated macrophages, reveal that HIV resistance to some NRTIs may be less efficient in these cells and indicate that resistance-associated loss of RC is more pronounced in macrophages than in high-dNTP content cell systems.