Use of anti-idiotypic antibodies as cell-surface receptor probes.
Anti-idiotypic antibodies have been raised against antibodies to retinol-binding protein (RBP) and to insulin. After absorption the anti-idiotypic antibodies recognized the antigen-combining sites of the antibodies used as the immunogen but of no other antibodies. Some of the anti-idiotypic antibodies raised against antibodies to RBP bound specifically to rat intestine epithelial cells, which have a physiological cell-surface receptor for RBP. The RBP receptor mediates the uptake of retinol from RBP to the cells. This uptake was abolished in a concentration-dependent manner by the anti-idiotypic antibodies, which obviously competed with RBP for binding to the receptor.Anti-idiotypic antibodies against antibodies to insulin inhibited the binding of (125)I-labeled insulin to isolated rat epididymal fat cells, whereas anti-idiotypic antibodies raised against antibodies to RBP had no effect. Furthermore, on interacting with young rat thymocytes, anti-idiotypic antibodies against antibodies to insulin stimulated the uptake by the cells of alpha-aminoisobutyric acid, thereby mimicking the effect of insulin. These results suggest that in some cases anti-idiotypic antibodies may be useful tools in elucidating structure-function relationships for cell-membrane receptors.
D000621:Aminoisobutyric Acids / Q000378:metabolism; D000888:Antibodies, Anti-Idiotypic; D000918:Antibody Specificity; D000937:Antigen-Antibody Reactions; D001665:Binding Sites; D001666:Binding Sites, Antibody; D007135:Immunoglobulin Variable Region; D007328:Insulin / Q000276:immunology*; D007413:Intestinal Mucosa / Q000378:metabolism; D011972:Receptor, Insulin / Q000378:metabolism*; D011955:Receptors, Drug / Q000378:metabolism*; D012177:Retinol-Binding Proteins / Q000276:immunology*; D013950:Thymus Gland / Q000378:metabolism
D000621:Aminoisobutyric Acids; D000888:Antibodies, Anti-Idiotypic; D007135:Immunoglobulin Variable Region; D007328:Insulin; D011955:Receptors, Drug; D012177:Retinol-Binding Proteins; D011972:Receptor, Insulin