Studying Platelet-Hiv Interactions and Potential to Promote Viral Spread

Abstract HIV-infected individuals experience persistent inflammation, which is associated with increased platelet activation. There is growing evidence that platelets contribute to immune responses, through the release of inflammatory granules and complex formation with other cells including monocytes and CD4+ T-cells, both of which are susceptible to infection. Previous studies have found evidence that HIV is engulfed by platelets. However, such studies were primarily conducted in vitro. It is important to study consequences of HIV-platelet interactions, and to ascertain whether or not they occur in patients. We confirmed previous in vitro findings through co-culturing platelets from healthy donors, with HIV virions, and using electron microscopy identified virus-like particles inside platelets. Utilizing RNAscope in tandem with RT-PCR we created a timeline of virus-platelet associations and found viral genomic RNA remained associated with platelets for a prolonged period of time. Importantly, platelet-associated virus remained infectious, as platelets were able to spread infection to activated CD4+ T-cells in coculture experiments. Furthermore, we established a system to screen for HIV-positive platelets. We isolated platelets from cART-naïve viremic patients and performed super resolution microscopy and imagestream flow cytometry. This analysis revealed evidence of HIV-positive platelets in these infected individuals. In contrast, the amount of HIV-positive platelets was drastically, although not entirely, reduced following 3 months of cART treatment. Our findings suggest that platelet-virus interactions may be important in contributing to viral spread, and the development and maintenance of viral reservoirs.