EXPRESSION OF THE SUPERANTIGEN MYCOPLASMA-ARTHRITIDIS MITOGEN IN ESCHERICHIA-COLI AND CHARACTERIZATION OF THE RECOMBINANT PROTEIN

Mycoplasma arthritidis mitogen (MAM), is a soluble protein with classi cal superantigenic properties and is produced by an organism that caus es an acute end chronic proliferative arthritis, Unfortunately, the pr ocess of obtaining purified MAM from M. arthritidis culture supernatan ts is extremely time-consuming and costly, and very little material is recovered, Thus, our Laboratory has expressed MAM in Escherichia coli by using a protein fusion expression system, The construction and exp ression of recombinant MAM (rMAM), as weil as a comparison of the biol ogical properties of rMAM to those of native MAM, are discussed. Brief ly, conversion of the three UGA codons to UGG codons was required to o btain full-length expression and mitogenic activity of rMAM. Antisera to native MAM recognized both rMAM and the fusion protein, The T-cell receptor V-beta and major histocompatibility complex class II receptor usages by rMAM and the fusion protein were identical to that of nativ e MAM, In addition, the ability to induce suppression and form the sup erantigen bridge could also be demonstrated with rMAM. Importantly, do se-response experiments indicated that homogeneous native MAM and rMAM were of equal potency, Thus, MAM has been successfully expressed in E . coli, thereby creating a viable alternative to native MAM.