Gangliosides are sialylated glycosphingolipids present in plasma cell membranes. They are particularly concentrated in the nervous system. Gangliosides have been implicated as playing major roles in cellular interactions and signal transduction. Based on the oligosaccharide structures, gangliosides can be categorized into several major families, including ganglio-series and neolacto-series. While ganglio- series gangliosides are present in both the central nervous system (CNS) and peripheral nervous system (PNS), the neolacto-series gangliosides are present mainly in the PNS. The major neolacto- series gangliosides of human PNS are LM1 and Hex-LM1. Gangliosides have been implicated as antigens in various autoimmune neuropathies. For example, anti-GM1 antibodies are associated with motor neuropathy, anti-GD1a antibodies are associated with acute motor axonal neuropathy, anti-LM1 antibodies are associated with the Guillain-Barre syndrome (GBS) and anti-GQ1b antibodies are associated with Miller Fisher syndrome, a variant of GBS. The role of antibodies to neolacto-series gangliosides in autoimmune peripheral neuropathies and the localization and function of these gangliosides remain unknown. This is partly due to the lack of specific probes for these gangliosides. One reason for the lack of probes such as specific antibodies is that it is difficult to isolate large quantities of these gangliosides from peripheral nerves. Interestingly, LM1 ganglioside is also present in human red blood cells. We have used human blood to isolate and purify large quantities of LM1. The overall objective of this study is to develop high-affinity specific antibodies against neolacto-series gangliosides. We propose to achieve our objective in two specific aims.
In Specific Aim 1, we will develop mouse monoclonal antibodies using purified LM1 conjugated to keyhole limpet hemocyanin (KLH) as an immunogen.
In Specific Aim 2, we will generate polyclonal antibodies in New Zealand white rabbits by immunizing them with LM1 mixed with KLH and emulsified in Freund's adjuvant. Our study should lead to the development of high-affinity IgG antibodies to LM1 and Hex-LM1. The availability of polyclonal and a panel of monoclonal antibodies to the neolacto-series gangliosides will provide very powerful tools to elucidate their localization and biological function in the peripheral nerves. These antibodies will also be very useful to delineate their pathogenic potential in autoimmune diseases of the peripheral nervous system.
Specific reagents such as monoclonal antibodies to peripheral nervous system neolacto- series gangliosides are currently not available. Development of high-affinity antibodies to these important gangliosides would provide powerful tools to probe their physiological functions in health and disease.
