Binding properties of goat IgM anti-dinitrophenyl antibodies

Goats immunized over 2 months with low doses of 1 mg/kg of dinitrophenylated Salmonella typhimurium responded with low levels of anti-DNP antibodies restricted to the IgM class. The purified antibodies show low association constants (Ka between 10(4) of 10(5) l/M), a high degree of homogeneity (heterogeneity indices alpha between 0.7 and 0.9) and ten combining sites when tested against dinitrophenyl-lysine as ligand by equilibrium dialysis. These binding properties remained unchanged during the whole immune response. When after 9 months the animals received the same immunogen and DNP-BGG, the anti-DNP antibody response included antibodies in the IgG class.