Platelets function as an acute viral reservoir during HIV-1 infection by harboring virus and T-cell complex formation.

Platelets were recently found to harbor infectious HIV virions in infected individuals who are on antiretroviral treatment with poor CD4+ T-cell recovery. In this study, we screened platelets from recently infected individuals, before and after antiretroviral therapy, for the presence of virus and examined platelet activation, as well as CD4+ T-cell recovery. This was followed by in vitro studies assessing platelet-CD4+ T-cell complex formation as a contributing factor to viral transmission.

Monocytes complexed to platelets differentiate into functionally deficient dendritic cells.

In addition to their role in hemostasis, platelets store numerous immunoregulatory molecules such as CD40L, TGFβ, β2-microglobulin, and IL-1β and release them upon activation. Previous studies indicate that activated platelets form transient complexes with monocytes, especially in HIV infected individuals and induce a proinflammatory monocyte phenotype. Because monocytes can act as precursors of dendritic cells (DCs) during infection/inflammation as well as for generation of DC-based vaccine therapies, we evaluated the impact of activated platelets on monocyte differentiation into DCs.

Synthesis and Characterization of Cobalt(II) ,'-Diphenylazodioxide Complexes.

Removal of chloride from CoCl with TlPF in acetonitrile, followed by addition of excess nitrosobenzene, yielded the eight-coordinate cobalt(II) complex salt [Co{Ph(O)NN(O)Ph}](PF), shown by single-crystal X-ray analysis to have a distorted tetragonal geometry. The analogous treatment of the bipyridyl complex Co(bpy)Cl yielded the mixed-ligand cobalt(II) complex salt [Co(bpy){Ph(O)NN(O)Ph}](PF), whose single-crystal X-ray structure displays a trigonal prismatic geometry, similar to that of the iron(II) cation in the previously known complex salt [Fe{Ph(O)NN(O)Ph}](FeCl). The use of TlPF to generate solvated metal complex cations from chloride salts or chlorido complexes, followed by the addition of nitrosobenzene, is shown to be a useful synthetic strategy for the preparation of azodioxide complex cations with the noncoordinating, diamagnetic PF counteranion.