CLONING AND DNA-SEQUENCE OF A 29 KILODALTON POLYPEPTIDE GENE OF MYCOPLASMA-GALLISEPTICUM AS A POSSIBLE PROTECTIVE ANTIGEN

A lambdagt11 clone, designated M1 and having a 0.8 kilobase (kb) inser t, was selected by screening a Mycoplasma gallisepticum (M.g.) genomic DNA library with antisera against M.g. cells and their membrane prote ins. The sequence of a 1.7 kb EcoRI fragment of genomic DNA covering t he entire M1 insert revealed a long open reading frame, TM-1, that enc oded a polypeptide with a deduced molecular weight of 29 kDa. An antis erum raised in chicken against the TM-1 polypeptide, which was produce d by recombinant Escherichia coli cells and purified by column chromat ography, inhibited growth of M.g. cells in vitro. Moreover, chickens i mmunized with this polypeptide were partially protected from a challen ge with virulent M.g. This polypeptide may serve as the basis for a va ccine against M.g. infection.