Abstract: This study aims at tick vitellogenesis and its mechanism. Six hybridoma cell lines secreting monoclonal antibody (McAb) against vitellin (Vn) of the hard tick Haemaphysalis longicornis were produced by fusing myeloma cells (SP2/0) with spleen cells, both from BALB/c mouse which were immunized with the Vn. They were named as 1B5, 2A7, 2B8, 2F2, 3A1 and 3G1, respectively. Further identification indicated that 1B5, 2B8 and 2F2 were of the isotype IgGA, 2A7 was of the isotype IgG1, while 3A1 and 3G1 were of the isotype IgG2a. All the six antibodies had high specificity and affinity, and their titers were over 10^-5. SDS-PAGE and affinity analysis of 1B5, whose specificity and titer were the highest, indicated that the molecular masses of its heavy chain and light chain were 58 kD and 21 kD, respectively, and the affinity constant was 2.8993×10^-6. Western blot analysis showed that the six antibodies had specific immunological reaction with the eight subunits of the Vn. The six McAbs against the Vn of H. longicorns prepared and identified successfully in this study may provide an important tool for further elucidating vitellogenesis and its regulation mechanism in H. longicorns.

Key words: Haemaphysalis longicornis, vitellin, monoclonal antibodies, molecular characteristics, subunit identification