hree hybridoma cell strains which could stably secrete McAbs to Mycoplasma pulmonis were established by hybridoma technique and coded BAllBD7, BG12 respectively. The study indicated that the McAbs produced bythe three strains were specific for M. pulmonis and didn't cross reactwith many other Mycoplasma species such as M.arthritidis, M. arginint,M. hyorhinis, and M. orale and so on. The three McAbs were all IgG