An antibody to dopamine D2 receptor inhibits dopamine antagonist and agonist binding to dopamine D2 receptor cDNA transfected mouse fibroblast cells.
A polyclonal antibody to dopamine D2 receptor (D2-receptor) has been used to examine the immuno-inhibition in the binding of a D2 antagonist, [3H]YM09151-2 and an agonist, PPHT-fluorescein to dopamine receptor DNA transfected mouse fibroblast cells. The specific activity of the [3H]YM09151-2 binding to transfected (Ltk-RGB) cells is 4-5 fold higher than untransfected (Ltk-) cells. The antibody is able to inhibit the [3H]YM09151-2 binding to the cell membranes from Ltk-RGB cells (Bmax 110.56 +/- 5.26 and 76.20 +/- 5.18 fmoles/mg protein in the presence of preimmune and immune sera, respectively, with no change in the Kd). The flow cytometric analysis of the PPHT-fluorescein labeled Ltk- and Ltk-RGB cells indicated that ligand specific fluorescence is associated only with small Ltk-RGB cells (second peak) and autofluorescence with large cells (first peak). Preincubation of the Ltk-RGB cells with antibody, reduced the fluorescence intensity of the PPHT-fluorescein by 20-25% without changing the auto-fluorescence. These results suggest that peptide antibody recognize D2-receptor in both membranes and in intact cells and interact at or near the ligand binding site of the receptor.
Farooqui
S M
SM
Laboratory of Neurosciences, Pennington Biomedical Research Center, Baton Rouge, LA 70808.
Prasad
C
C
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000918:Antibody Specificity; D001549:Benzamides / Q000378:metabolism; D002478:Cells, Cultured; D015259:Dopamine Agents / Q000378:metabolism*; D018492:Dopamine Antagonists; D005347:Fibroblasts / Q000378:metabolism*; D005434:Flow Cytometry; D005452:Fluoresceins / Q000378:metabolism; D051379:Mice; D017448:Receptors, Dopamine D2 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D014162:Transfection
C077797:2-(N-phenylethyl-N-propyl)amino-5-hydroxytetralin fluorescein; D000906:Antibodies; D001549:Benzamides; D015259:Dopamine Agents; D018492:Dopamine Antagonists; D005452:Fluoresceins; D017448:Receptors, Dopamine D2; D011994:Recombinant Proteins; C030265:nemonapride