Serological responses in birds vaccinated with TS-11

摘要

Work has been carried out to assess the efficacy of this vaccine against Mycoplasma gallisepticum using different methods of testing. TS-11 is a live attenuated Mycoplasma gallisepticum (MG) vaccine developed in Australia and used extensively all over the world. This strain is a chemically induced mutant of a naturally occurring field strain and was selected for its ability to grow well at 33 deg C but poorly at 39.5 deg C. The rapid serum plate agglutination (RSPA) test is a very effective tool todetermine the immunological response of birds vaccinated with TS-11 because it allows the detection of antibodies against MG after vaccination. Unfortunately, this technique is highly sensitive and is characterised by producing nonspecific reactions known as false positives. These reactions are caused by the type of antigen used in the test, the vaccination programme used on the evaluated birds and the cross-reactions induced by other pathogens. The differences in the levels of sensitivity of the antigen have been extensively documented, and that is why diagnostic laboratories regularly retest positive sera using the HI (haemagglutination inhibition) test. Some laboratories dilute the serum tested in an effort to eliminate the non-specific reactions.