Binding of monoclonal anti-myelin-associated glycoprotein antibodies to human foetal peripheral neurons in culture

Adeno-associated virus and lentivirus vectors mediate efficient and sustained transduction of cultured mouse and human dorsal root ganglia sensory neurons

Peripheral nervous system (PNS) sensory neurons are directly involved in the pathophysiology of numerous inherited and acquired neurological conditions. Therefore, efficient and stable gene delivery to these postmitotic cells has significant therapeutic potential. Among contemporary vector systems capable of neuronal transduction, only those based on herpes simplex virus have been extensively evaluated in PNS neurons. We therefore investigated the transduction performance of recombinant adeno-associated virus type 2 (AAV) and VSV-G-pseudotyped lentivirus vectors derived from human immunodeficiency virus (HIV-1) in newborn mouse and fetal human dorsal root ganglia (DRG) sensory neurons. In dissociated mouse DRG cultures both vectors achieved efficient transduction of sensory neurons at low multiplicities of infection (MOIs) and sustained transgene expression within a 28-day culture period. Interestingly, the lentivirus vector selectively transduced neurons in murine cultures, in contrast to human cultures, in which Schwann and fibroblast-like cells were also transduced. Recombinant AAV transduced all three cell types in both mouse and human cultures. After direct microinjection of murine DRG explants, maximal transduction efficiencies of 20 and 200 transducing units per neuronal transductant were achieved with AAV and lentivirus vectors, respectively. Most importantly, both vectors achieved efficient and sustained transduction of human sensory neurons in dissociated cultures, thereby directly demonstrating the exciting potential of these vectors for gene therapy applications in the PNS.

Complement-mediated demyelination in patients with IgM monoclonal gammopathy and polyneuropathy

We investigated the role of complement in the pathogenesis of the demyelinating polyneuropathy that occurs in some patients with IgM monoclonal gammopathy. Seven patients with chronic sensorimotor polyneuropathy and IgM monoclonal gammopathy were examined. In six patients, the monoclonal protein recognized an epitope shared by myelin-associated glycoprotein and two peripheral-nerve glycolipids, whereas in one patient, IgM bound to an unidentified myelin antigen. Direct and indirect immunofluorescence and immunoperoxidase assays showed colocalization along the myelin sheaths of peripheral-nerve fibers of monoclonal protein with complement components C1q, C3d, and C5. In addition, terminal-complement complex that was not associated with S protein was detected in myelin sheaths. It appeared that alterations in myelin geometry caused by the separation of myelin lamellae corresponded to sites at which terminal-complement complex was deposited. We conclude that demyelination in polyneuropathy associated with IgM monoclonal gammopathy may be mediated by complement.