PRELIMINARY FINDINGS OF AN IN-VITRO HUMAN SPLEEN MONONUCLEAR CELL-CULTURE SYSTEM FOR PRIMARY ISOLATES OF HIV TYPE-1

Acute HIV-1 infection is often manifested with a high level of viremia , The cell types and tissues/organs that contribute to the virus load are thought to be of central and peripheral lymphoreticular origin, Th e establishment and permissiveness of organ-based cell culture systems from spleen with laboratory strains or primary isolates of HIV-1 have not been reported, We studied unseparated splenic mononuclear cells ( SMCs) and adherent cells derived from human spleen and liver in compar ison with blood monocyte-derived macrophages (MDMs), Unstimulated, SMC s were highly permissive to primary lymphotropic HIV-1 and dual/macrop hage-tropic isolates (which are able to replicate in both MDMs and PBM Cs). Furthermore, SMCs were found to replicate virus to high titer in a rapid log-phase manner and exhibited a prolonged stationary phase of virus production, unlike PBMCs, which required conventional activatio n with mitogens and exhibited a much shorter period of virus productio n, Interestingly, the SMCs maintained themselves as a mixed phenotype of nested lymphocytes with complex and well-differentiated macrophage( s) for extended periods of time, In addition, splenic macrophages read ily purified by adherence were highly permissive to a dual/macrophage- tropic primary isolate, HIV-1(ADA), intermediate with two laboratory s trains, HIV-1(RF) and HIV-1(HXB3), and least permissive to the lymphot ropic primary isolate HIV-1(Mr452) and two other laboratory strains, H IV-1(CC) and HIV-1(MN). The replication of HIV-1(ADA) as measured by e xtracellular p24 was sustained for up to 7 weeks and similar to the re plication patterns observed with adherent hepatic macrophages and bloo d-derived MDMs, This study demonstrates that exogenous stimulation is not required for infection of these cells; either adherence-isolated a nd/or mixed lymphoid populations can be studied together, and viable s tocks can be readily prepared and cryopreserved, In addition, these ce lls could be used for isolating new and/or other variants of HIV-1. Th us, the use of the SMC primary in vitro cell culture system for future studies involving HIV-1 is warranted.