Abstract: 【Aim】 In order to accurately track the synthesis, transport pathway and absorption of vitellogenin (Vg) in Harmonia axyridis (Pallas) as well as the accumulation and distribution of vitellin (Vn) in the oocytes, the monoclonal antibody (McAb) against Vn of H. axyridis was prepared. 【Methods】 The hybridoma cell lines secreting McAb against Vn of H. axyridis were produced by using hybridoma techniques, based on the cells from BALB/c mouse which were immunized with the Vn. 【Results】 We produced four monoclonal antibodies to H. axyridis soluble yolk proteins, i.e., 5E2, 5E11, 1E9 and 5H8. Further identification indicated that 1E9, 5E11 and 5E2 were the isotype IgG1, and 5H8 was the isotype IgM. Western blot analysis showed that the four antibodies had high specificity and affinity to the Vn. However, they showed no immunological reaction with the male haemolymph. 5E2 and 1E9 had specific immunological reaction with the four subunits of the Vn. Finally, we selected 5E2 whose titer was the highest before ascites preparation to prepare the monoclonal antibodies. SDS-PAGE indicated that the molecular masses of 5E2 heavy chain and light chain were 50 and 27 kD, respectively, and its titer was 1:81 000. 【Conclusion】 The successful preparation and identification of H. axyridis McAb may establish an essential tool for further building the ELISA method for assaying its dynamics.

Key words: Harmonia axyridis, vitellin (Vn), monoclonal antibody (McAb), isotype, subunit identification