RESUMO
OBJECTIVE: To investigate the change of specific antibodies IgG, IgG1 subclass and IgE in sheep infected with Echinococcus granulosus (E. g) during anaphylactic shock, and to observe antigen B reactivity against IgG antibody in E. g-infected sheep. METHODS: Antigen B and crude antigen were prepared with E. g cyst fluid (EgCF) from infected sheep. The enzyme-linked immunosorbent assay(ELISA) was used for detecting the level of specific IgG, IgG1 and IgE during anaphylactic shock in sheep induced by E. g. RESULTS: The level of specific IgG, IgG1 and IgE was significantly higher in the infected sheep after 6 months than that of the uninfected control group (P < 0.01). The IgE level decreased rapidly after anaphylactic shock induced, especially when the sheep was dying. Following an antigen challenge the sheep showed a general decrease in total IgG and IgG1 subclass. The total IgG showed a slight change at the beginning, followed by a decrease 1 h after challenge. The decrease of IgG1 subclass was more significant than the total IgG in 40 min after challenge injection. The positive rate was 91% for antigen B and 32% for crude antigen of EgCF against IgG antibody in E. g-infected sheep. CONCLUSION: The specific IgE plays a major role in the anaphylactic shock, while IgG and IgG1 antibodies are also important. Antigen B derived from sheep E. g cyst fluid appears to be useful in serodiagnosis of and monitoring on the infection status in sheep.