IgG anti-Galnac-GD1a antibodies bind to neuromuscular junctions of rat hemidiaphragm

Introduction: We investigated the localization of a ganglioside, N‐acetylgalactosaminyl GD1a (GalNAc‐GD1a), in peripheral nerves with an IgG anti–GalNAc‐GD1a antibody, which was produced in rabbits immunized with GalNAc‐GD1a. Methods: Teased fibers from ventral and dorsal roots and hemidiaphragm sections of rats were assessed using fluorescent double‐ and triple‐labeling methods. Results: The nodal and paranodal regions of teased fibers from ventral roots were immunostained with IgG anti–GalNAc‐GD1a antibodies. After collagenase treatment, no staining was seen with IgG anti–GalNAc‐GD1a or anti‐NF200 antibodies, whereas α‐bungarotoxin selectively stained nerve terminals. In cross‐sectional and longitudinal sections of rat hemidiaphragm, IgG anti–GalNAc‐GD1a antibodies overlapped with α‐BuTx and anti‐NF200 antibodies, indicating that GalNAc‐GD1a is localized to the nerve terminal. IgG anti–GalNAc‐GD1a antibody staining also overlapped with that of AChR clusters and syntaxin‐positive presynaptic nerve terminals. Conclusion: GalNAc‐GD1 is localized in both pre‐ and postsynaptic nerve terminals of neuromuscular junctions. Muscle Nerve 46: 705–710, 2012