Combined effects of a thymic peptide, thymopoietin and myasthenic patient sera in rat myotube culture.
We investigated in a rat myotube assay the combined effect of 26 myasthenic (MG) patient sera and a thymic peptide, thymopoietin (Tpo) which had previously been shown to bind Torpedo and human AChR and to compete with alpha-bungarotoxin (alpha-Bgt) binding. Cultures were first exposed to Tpo alone for 3 h (0.3, 7.5, 15 nM), then MG sera (5% final dilution) were added for an additional 18 h. Reduction in the amount of 125I-alpha-Bgt binding sites in the presence of various concentrations of Tpo were similar with control sera and in all the patients with low or undetectable anti-AChR Ab (11 cases). In cultures exposed to Tpo and sera with high anti-AChR Ab titre (15 cases), Tpo and anti-AChR Ab have an additive capacity to reduce the number of alpha-Bgt binding sites. The results are compatible with the hypothesis that anti-AChR Ab and Tpo could impair neuromuscular transmission by complementary mechanisms.
Eymard
B
B
Centre Chirurgical Marie Lannelongue, CNRS URA-1159, Le Plessis-Robinson, France.
Aimé
C
C
Cottin
C
C
Morel
E
E
Goldstein
G
G
Bach
J F
JF
Berrih-Aknin
S
S
D000110:Acetylcholinesterase / Q000276:immunology; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D002038:Bungarotoxins / Q000378:metabolism; D002478:Cells, Cultured; D005260:Female; D005453:Fluorescence; D006801:Humans; D007457:Iodine Radioisotopes; D008024:Ligands; D009132:Muscles / Q000166:cytology / Q000187:drug effects*; D009157:Myasthenia Gravis / Q000097:blood*; D011247:Pregnancy; D011869:Radioligand Assay; D051381:Rats; D013934:Thymectomy; D013946:Thymopoietins / Q000378:metabolism / Q000494:pharmacology*
D002038:Bungarotoxins; D007457:Iodine Radioisotopes; D008024:Ligands; D013946:Thymopoietins; D000110:Acetylcholinesterase