Antibodies to recombinant synaptotagmin and calcium channel subtypes in Lambert-Eaton myasthenic syndrome

J Neurol Sci. 1995 Nov;133(1-2):95-101. doi: 10.1016/0022-510x(95)00162-u.


Several proteins have been postulated as possible targets of immune attack in Lambert-Eaton myasthenic syndrome (LEMS). Heterogeneity of autoantibodies in sera from 20 LEMS patients was studied by comparing their reactivity to synaptotagmin, a synaptic vesicle protein, and voltage-gated calcium channels (VGCCs). Six patients' sera (1 with small cell lung carcinoma (SCLC)) contained antibodies specifically recognizing the recombinant synaptotagmin on immunoblots. Thirteen (11 with SCLC) and 16 (11 with SCLC and 1 with poorly differentiated cell carcinoma in the lung) patients' sera immunoprecipitated omega-conotoxin GVIA-labeled N-type and omega-conotoxin MVIIC-labeled Q-type VGCCs, respectively. Three of 6 synaptotagmin-positive sera had cross-reactivity with N and/or Q subtypes of VGCC; the remaining 3 showed no cross-reactivity with VGCCs. Results indicate that LEMS sera are heterogeneous in the spectrum of containing antibodies, and suggest that this heterogeneity reflects the immune response to various synaptic proteins including not only multiple VGCCs but also synaptosecretory complex proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Autoantibodies / blood*
  • Calcium Channels / immunology*
  • Calcium-Binding Proteins*
  • Carcinoma, Small Cell / immunology
  • Carcinoma, Small Cell / physiopathology
  • Cell Differentiation / immunology
  • Female
  • Humans
  • Immunoblotting
  • Ion Channel Gating
  • Lambert-Eaton Myasthenic Syndrome / immunology
  • Lambert-Eaton Myasthenic Syndrome / physiopathology*
  • Lung Neoplasms / immunology
  • Lung Neoplasms / physiopathology
  • Male
  • Membrane Glycoproteins / immunology*
  • Middle Aged
  • Nerve Tissue Proteins / immunology*
  • Paraneoplastic Syndromes / immunology
  • Paraneoplastic Syndromes / physiopathology
  • Precipitin Tests
  • Recombinant Proteins / immunology
  • Synaptotagmins


  • Autoantibodies
  • Calcium Channels
  • Calcium-Binding Proteins
  • Membrane Glycoproteins
  • Nerve Tissue Proteins
  • Recombinant Proteins
  • Synaptotagmins