Antibodies against (1R,2R)-cyclohexanediamineplatinum(II)-DNA adduct recognize the conformational differences of isomeric analogues of cyclohexanediamine.
Antibodies reactive to (1R,2R)-cyclohexanediamineplatinum(II)-DNA ((1R,2R)-cyclohexanediamine: 1R,2R-dach) adducts were elicited by immunization of rabbit with calf thymus DNA modified by Pt(1R,2R-dach)Cl2 at a ratio of bound platinum per nucleotide ((D/N)b) of 0.0335. In an enzyme-linked immunosorbent assay (ELISA), the binding of specific antibodies to Pt(1R,2R-dach)-DNA adduct (60 microliters of 1.235 x 10(-7) M Pt in each wells) on the assay plate was competitively inhibited by Pt(1R,2R-dach)-DNA adduct ((D/N)b = 0.0653) in the solution. Almost equal inhibition was observed with Pt(1S,2S-dach)-DNA ((D/N)b = 0.0412), an optical isomer of 1R,2R-dach. Pt(1R,2S-dach)-DNA ((D/N)b = 0.0371) and Pt(1R,3S-dach)-DNA ((D/N)b = 0.0281) in which the cyclohexane ring is stereochemically perpendicular to the platinum chelate plane, also inhibited antibody binding, but these adducts gave only incomplete inhibition at higher Pt-DNA adduct concentrations. Although Pt(1R,2R-dach)-d(GpG) and Pt(1R,2R-dach)(NH3)2 inhibited antibody binding, the affinity of the antibody for Pt(1R,2R-dach)(NH3)2 was lower than with Pt(1R,2R-dach)-DNA, and the inhibition behavior of Pt(1R,2R-dach)-d(GpG) was biphasic, i.e., at the lower concentration the inhibition curve was consistent with that of Pt(1R,2R-dach)-DNA, but at the higher concentration it shifted to that of Pt(1R,2R-dach)(NH3)2. The affinity of the antibody for cis-DDP was markedly lower than with Pt(1R,2R-dach)(NH3)2. These facts suggest that the antibodies may bind to the substituents (the platinum and its surroundings) of the various Pt complexes rather than the DNA structure altered by platinum binding.
Yamada
H
H
Faculty of Pharmaceutical Sciences, Nagoya City University, Japan.
Kato
T
T
Hirose
J
J
Inagaki
K
K
Noji
M
M
Kidani
Y
Y
D000818:Animals; D000918:Antibody Specificity; D001667:Binding, Competitive; D002417:Cattle; D003429:Cross Reactions; D003510:Cyclohexanes / Q000276:immunology*; D003514:Cyclohexylamines / Q000276:immunology*; D004247:DNA / Q000276:immunology*; D018736:DNA Adducts; D004797:Enzyme-Linked Immunosorbent Assay; D008968:Molecular Conformation; D009690:Nucleic Acid Conformation; D009944:Organoplatinum Compounds; D013237:Stereoisomerism
C065354:1,2-cyclohexanediamine platinum(II)-DNA complex; D003510:Cyclohexanes; D003514:Cyclohexylamines; D018736:DNA Adducts; D009944:Organoplatinum Compounds; D004247:DNA; C030435:1,2-cyclohexanediamine