IgM/IgG solid-phase antibody-capture assay with biotin/125I-streptavidin amplification: application to normal human sural nerve biopsies.
A highly sensitive and specific solid-phase antibody-capture assay was developed to measure IgM and IgG in endoneurial preparations of human sural nerve biopsies. Assay amplification was obtained by utilizing biotin-labeled anti-IgM or anti-IgG antibody and 125I-streptavidin, resulting in multiple streptavidin molecules binding per biotinylated antibody molecule. A minimal detectable dose of 0.16 +/- 0.08 ng (mean +/- SD; n = 7) for IgM and 0.03 +/- 0.02 ng (mean +/- SD; n = 5) for IgG was obtained in a 100 microliters sample. When this assay was applied to normal fascicular biopsies from human sural nerve, the percent of IgM and IgG, respectively, of the total endoneurial protein was 0.026 +/- 0.015% (n = 9) and 0.27 +/- 0.15% (n = 10; mean +/- SD). When these endoneurial concentrations of IgM and IgG were related to the plasma concentrations (mg IgM or IgG/mg total plasma protein), an IgM-blood-nerve barrier (BNB) index of 4.09 +/- 1.95 and an IgG-BNB index of 2.07 +/- 1.10 were obtained (X10(2); mean +/- SD). These values were also related to the albumin (Alb) concentration in the biopsies as a percent of total endoneurial protein (2.48 +/- 1.07%; mean +/- SD) and with the Alb-BNB index (5.40 +/- 2.53; X10(2); mean +/- SD; n = 10). Although these normal values will be expected to change with age, sex, nerve, and proximal-distal distance from nerve root, they should provide a basis for the comparison of BNB indices from patients with peripheral neuropathy.
Poduslo
J F
JF
Department of Neurology, Mayo Clinic, Rochester, MN 55905.
Curran
G L
GL
Brunden
K R
KR
Dyck
P J
PJ
D000328:Adult; D001426:Bacterial Proteins; D001706:Biopsy; D001710:Biotin; D002199:Capillary Permeability; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis*; D007150:Immunohistochemistry / Q000379:methods; D007457:Iodine Radioisotopes; D008297:Male; D011863:Radioimmunoassay / Q000379:methods*; D012709:Serum Albumin / Q000032:analysis; D013127:Spinal Nerves / Q000032:analysis*; D019809:Streptavidin; D013497:Sural Nerve / Q000032:analysis* / Q000098:blood supply
D001426:Bacterial Proteins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007457:Iodine Radioisotopes; D012709:Serum Albumin; D001710:Biotin; D019809:Streptavidin