Isolation and purification of anaphylactic antibody from guinea pig and preliminary research on its role in passive cutaneous anaphylaxis test (PCA)
Objective To establish guinea pig model of type Ⅰ anaphylaxis, isolate the anaphy-lactic antibody(IgE and IgG) preliminarily from sera of sensitized guinea pigs, and investigate its functional characteristics. Methods Animal model was established by sensitizing guinea pigs with OVA and Al(OH)_3, level of antibody was determined by ELISA, IgE and IgG in sera were preliminarily isolated through saturated ammonium sulphate precipitate and affinity chromatograph of Protein A. A continuous passive cutaneous ana-phylaxis test (PCA) was performed by sensitizing guinea pigs individually with IgE and IgG and then challenging at different time , and the variation of blue spots in skin were observed after challenge . Results Concentration of IgE in model group and control group were 719.3750 ng/ml and 2.5250 ng/ml, the optical density of IgG in model group and control group were 0.9921 and 0.0174, the level of two antibodies in model group were significantly higher than that of control group (P<0.05). In 9 d continuous PCA test, the blue spot induced by IgE in skin lasted for 9 days and appeared the largest when challenged at day 5. The diameter of blue spot induced by IgG was the largest when challenged at day 2 and then decreased fast. Con-clusion Anaphylactic antibodies were successfully preliminarily isolated from sera of sensitizing guinea pig, both IgE and IgG play roles in type Ⅰ anaphylaxis of guinea pig, the hypersensitive reaction induced by IgG is fast and short than that induced by IgE, and IgG may become an important surrogate marker in immunotoxic-ity evaluation(type Ⅰ anaphylaxis)of vaccine. 
 
Key words: 
Guinea pig; Type Ⅰ anaphylaxis; Passive cutaneous anaphylaxis; IgE; IgG