POSTER Neurology, 2015
OBJECTIVE: To assess the presence of viral proteins in the CSF of patients with HTLV-1 associated myelopathy/ tropical spastic paraparesis (HAM/TSP) BACKGROUND: There has been increasing evidence for the role of microvesicles (MV) in CNS inflammation and viral disease. HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neuroinflammatory disease that affects a subset of virus-infected infected individuals. This disorder is immunopathologically mediated since virus -specific immune cells can be found in both the CSF and in the CNS of patients although HTLV-I virus has been difficult to isolate in CNS resident cells. The possibility of transfer of viral proteins via MV from viral reservoirs to uninfected cells in the absence of virus is an intriguing mechanism by which this can occur. Recently, HTLV-1 tax proteins have been shown in exosomes (EX) from HTLV-1 infected cell lines (Jaworksi et al 2014). Therefore, we examined if similar MV were present in the CNS of HAM/TSP patients. DESIGN/METHODS: HTLV-1 infected and uninfected cell line supernatants were used for isolation of EX and MV by a novel Nanotrap® (NT) technology. These NTs are hydrogel particles consisting of high affinity aromatic baits surrounded by a sieving shell. HTLV-I viral proteins were assessed by Western blot analysis. HTLV-I virions were detected by RT-qPCR. In addition, EXs were isolated using this EX-NT from CSF of HAM/TSP patients and MS patients as controls. RESULTS: Exosomes were successfully isolated specifically from HTLV-1 infected cell lines that contained HTLV-I tax protein but lacked HTLV-I virions. Moreover, CSF from HAM/TSP patients and not from MS, also demonstrated exosomes that were HTLV-I tax Western blot positive. CONCLUSIONS: These results suggest the possibility that HTLV-I protein present in virus-free CSF can be a potential source of antigen in an inflammatory neuropathological disease.