PROTECTIVE IMMUNITY INDUCED IN CHICKEN BY A SINGLE IMMUNIZATION WITH MYCOPLASMA-GALLISEPTICUM IMMUNOSTIMULATING COMPLEXES (ISCOMS)

An experimental immunostimulating complex vaccine has been prepared fr om detergent (Mega-10) solubilized Mycoplasma gallisepticum (MG) antig ens. Sucrose gradient centrifugation, SDS-PAGE and immunoblotting stud ies demonstrated that the ISCOM vaccine contained virtually all of the immunodominant MG membrane proteins, including p64 and p56. Protectiv e immunity generated by the experimental MG ISCOM vaccine was demonstr ated in challenge experiments. Chickens immunized with a single dose c ontaining between 1 and 50 mu g of MG ISCOMs had significantly reduced lesion scores in the air sac after challenge. The reisolation of the challenge MG strain was significantly less frequent from the chickens in vaccinated groups than from the unvaccinated control group. Presenc e of humoral antibodies in chickens vaccinated with 1-25 mu g MG ISCOM s was not detectable by blocking ELISA or haemagglutination-inhibition before challenge. Chickens vaccinated once or twice with a 50 mu g do se were transitory positive by blocking ELISA and rapid plate agglutin ation before challenge. Copyright (C) Elsevier Science Ltd.