Pyrimidine-Specific Antibodies: Reaction with DNA's of Differing Base Compositions

The reactivity of antinucleoside antibodies with DNA was found to depend on the base composition of the DNA. Anti-thymine antibodies reacted with denatured T2 phage DNA whereas anti-cytosive antibodies did not. This was attributed to the absence of cytosine in T2 phage DNA, and to the failure of anti-cytosine to react with glucosylated hydroxymethylcytosine. DNA preparations with different base ratios were tested for their reactivity with anti-cytosine and anti-thymine antibodies. Using DNA denatured in the presence of formaldehyde, which prevented reformation of base-paired structures, the reaction of Clostridium perfringens and Micrococcus lysodeikticus DNA's with anti-cytosine and anti-thymine antibodies could be correlated with the DNA base ratios. Calf thymus DNA reacted as expected from its base ratio with anti-thymine, but not as expected with anti-cytosine. The deviation observed in the anti-cytosine reaction pattern was related to an alteration in the antigenic identity of cytosine caused by formaldehyde during denaturation.