Interaction of a monoclonal antibody with the urease of Ureaplasma urealyticum

The monoclonal antibody (mAb) U.u. 5B2 against the urease of U. urealyticum (U.u) serotype 8, was affinity purified and was found to be an IgG 1 type, with an apparent dissociation constant of 2.9 × 10⁻¹⁰ M. Immunoblot analysis of the cytoplasmic proteins of U.u electrophoresed under non-denaturing conditions showed a reaction with a major and a minor band corresponding to the urease activity. The mAb, U.u.5B2 inhibited the urease activity up to 93% and precipitated a protein from the cytoplasm with a molecular weight of 75 kDa, corresponding to the purified urease subunit. This mAb also reacted with six other U.u serotypes but not with Jack bean urease, other urease containing bacteria or genital mycoplasma.