Detection of antibodies against wheat germ agglutinin bound glycoproteins on the islet-cell membrane.
An attempt was made to detect islet cell surface antibodies (ICSAb) using solubilized islet-cell glycoproteins as antigens. Isolated rat islets were labelled with 125I-wheat germ agglutinin (WGA) and solubilized by Nonidet P-40 with sonication. 125I-WGA-bound islet-cell proteins were incubated with test sera, and bound antibodies were precipitated with anti-human IgG or IgM immunobeads. Serum which had a bound percent beyond the mean plus 2SD of control sera was defined as antibody-positive. Results obtained by this method correlated well with those by the immunofluorescence method of detecting ICSAb. Prevalences of antibodies were 21/114 (18%) for IgG antibodies and 9/114 (8%) for IgM antibodies in patients with insulin-dependent diabetes mellitus (IDDM). The prevalence was highest for both IgG and IgM antibodies in patients within a year of the onset of disease (38 and 25%, respectively), and decreased thereafter. The prevalence of IgM antibodies was lower than that of IgG antibodies at all stages. In NIDDM patients, the prevalence of antibodies was 5/72 (7%) for both IgG and IgM antibodies. If these preliminary results are confirmed, this radioassay may be developed to detect antibodies against islet cell membrane proteins on a large scale.
Kitano
N
N
Department of Internal Medicine, Kyoto University School of Medicine, Japan.
Taminato
T
T
Ida
T
T
Seno
M
M
Seino
Y
Y
Matsukura
S
S
Kuno
S
S
Imura
H
H
D000818:Animals; D000906:Antibodies / Q000032:analysis*; D001798:Blood Proteins / Q000032:analysis; D005455:Fluorescent Antibody Technique; D007515:Islets of Langerhans / Q000032:analysis / Q000166:cytology*; D008562:Membrane Glycoproteins / Q000032:analysis / Q000276:immunology* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D014909:Wheat Germ Agglutinins / Q000276:immunology* / Q000378:metabolism
D000906:Antibodies; D001798:Blood Proteins; D008562:Membrane Glycoproteins; D014909:Wheat Germ Agglutinins