The effect of 'irrelevant' IgG protein selection on target uptake ratios of radiolabeled antibodies.
The uptake ratios of radiolabeled antibodies (Ab) commonly are two to three times the uptake ratios of the normal surrounding tissue. In an experimental crush injury model, we also defined a two to three times greater range of uptake of type I anticollagen antibody (Ac-Ab-I) from 1.5 hours to 48 hours after tail injury in the rat. Specific target uptake, however, often is further categorized by comparing the uptake ratio of Ab to that of a nonspecific protein. We present data to indicate that this nonspecific uptake may represent a significant variable. We found that sheep IgG gave consistently less nonspecific uptake in our model than did rabbit IgG. In the acute model (protein injected 1.5 hours after injury), damaged: normal tail ratios were Ac-Ab-I = 2.34, sheep = 0.8, and rabbit = 1.6. The extent of specific Ab uptake seems dependent upon the choice of "irrelevant" IgG controls.
Freimanis
R
R
Bowman Gray School of Medicine, Department of Radiology, Winston-Salem, North Carolina.
Zoghbi
S S
SS
Gottschalk
A
A
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D003094:Collagen / Q000276:immunology*; D004912:Erythrocytes; D007074:Immunoglobulin G / Q000276:immunology*; D007205:Indium Radioisotopes; D011877:Radionuclide Imaging; D051381:Rats; D011971:Receptors, Immunologic / Q000276:immunology*; D013623:Tail / Q000000981:diagnostic imaging / Q000293:injuries; D013667:Technetium
D000906:Antibodies; D007074:Immunoglobulin G; D007205:Indium Radioisotopes; D011971:Receptors, Immunologic; D013667:Technetium; D003094:Collagen