Non-specific binding of normal human IgG, including F(ab')2 and Fc fragments, to embryonic rat brain neurons and human cortex synaptosomes.
Binding of normal human IgG to embryonic rat brain neurons was quantitated by flow cytometry. IgG binding was linear between 0.05 and 1.5 mg/ml; slight binding was detectable even at normal cerebrospinal fluid concentrations. Similar binding curves were obtained for purified Fc and F(ab')2 fragments from normal human IgG. Normal human IgG also bound to synaptosomes (resealed nerve terminals) from human cerebral cortex. However, competition assays utilizing 125I-IgG showed no evidence for specific binding. This study indicates that the specificity of putative anti-neuronal antibodies should be confirmed by competition assays as for other receptor-ligand binding.
Loeffler
D A
DA
Department of Medicine, Sinai Hospital, Detroit, MI 48235.
Brickman
C M
CM
LeWitt
P A
PA
Bannon
M J
MJ
KuKuruga
M A
MA
Cassin
B
B
Kapatos
G
G
D000818:Animals; D001921:Brain / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism; D005333:Fetus / Q000378:metabolism*; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000378:metabolism*; D007141:Immunoglobulin Fc Fragments / Q000378:metabolism; D007074:Immunoglobulin G / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D051381:Rats / Q000196:embryology; D013574:Synaptosomes / Q000378:metabolism*; D013997:Time Factors
D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G