Immunogenic Properties of Native, Reconstituted and Hybrid Membranes of Mycoplasmas
The localization in the mycoplasma cell of the antigens responsible for the immunological response of the infected animal is of great interest for the development of vaccines composed of cell fractions rather than whole cells. It seems warranted to assume that, as in other microorganisms, the major immunogens are surface antigens located in the cell mambrane. That this is so is indicated in several recent papers (1–3). Growth and metabolism of the mycoplasmas were inhibited by antisera prepared against the membrane fraction, but not against the cytoplasmic fraction. In most mycoplasmas, membrane proteins appear to be the major immunogens, while in M. pneumoniae, the human pathogen, several membrane glycolipids fulfill this function. The serological characterization of membrane lipids is fairly easy compared with the antigenic analysis of membrane proteins, whose solubilization poses special problems. All the procedures known so far, in particular solubilization by detergents, involve variable degrees of protein denatura-tion. Nevertheless, our results indicate that the immunological activities of membrane proteins resist inactivation by detergents far better than the enzymic activities.