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In vitro modeling of the HIV‐macrophage reservoir
Author(s) -
Brown Amanda,
Zhang Hao,
Lopez Peter,
Pardo Carlos A.,
Gartner Suzanne
Publication year - 2006
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1189/jlb.0206126
Subject(s) - biology , green fluorescent protein , population , virology , provirus , flow cytometry , microbiology and biotechnology , gene , immune system , immunology , genetics , demography , genome , sociology
Macrophages are recognized as a putative reservoir for HIV‐1, but whether HIV can establish latent infection in this cell type is not known. An in vitro model using long‐term cultured primary human monocyte‐derived macrophages (MDM) infected with an M‐tropic, enhanced green fluorescent protein (EGFP) tagged reporter virus was developed to test the hypothesis that HIV can establish a latent infection of this cell type. The EGFP‐IRES‐Nef cassette allowed detection of early gene transcription. The expression of GFP+ MDM was followed with time and the GFP‐ population was purified and analyzed for evidence of latent infection. Interestingly, in MDM cultures propagated for over two months, distinct subpopulations of infected GFP+ cells were observed and quantitated. In particular, infected MDM that displayed a high level of transcription, characterized as the GFP hi group, yet produced low levels of the late viral gene product, p24, increased with time and represented 10% of the GFP+ population in long‐term cultures. The high level production of early genes such as Nef, a protein that can facilitate viral immune escape, but low level of structural proteins such as p24 in the GFP hi population suggests that a subset of infected MDM can exhibit an alternative mode of replication. The GFP‐ MDM population obtained by a two‐step purification protocol using flow cytometry and laser ablation contained integrated provirus as assessed by Alu‐LTR real‐time PCR analyses. A subset of these, were replication competent as shown by their ability to express GFP and/or p24 antigen after reactivation with IL‐4.