Characterization of the metabolism inhibition antigen of Mycoplasma arthritidis.

The Mycoplasma arthritidis antigen(s) responsible for eliciting metabolism-inhibiting antibodies in rabbits has been partially characterized. Metabolism-inhibiting activity was absorbed from rabbit antisera by intact M. arthritidis cells and membranes but much less so by the soluble cytoplasmic fraction, indicating that the antigen is located on the outer membrane surface. It was stable to periodate and lipid extraction but labile to heat and proteolytic enzymes, indicating that it is protein in nature. Finally, it is most likely a tightly bound integral rather than a peripheral membrane protein, since it was not extracted by low-ionic-strength solutions or by the nonionic detergents Triton X-100, Nonidet P-40, and Tween 20. It was solubilized by both the anionic agent sodium deoxycholate and the zwitterionic detergent Zwittergent. Two two monoclonal antibodies with metabolism-inhibiting activity were produced. One recognized a 45,000-dalton surface protein; however, the other recognized an antigen which is probably of cytoplasmic origin, indicating that more than one cell component may be involved in the metabolism-inhibiting antibody response.