Objective      To express the catalytic domain and non-catalytic domain of AaHIV from Agkistrodon acutus

and analyze the immunoprotective effects in mice.       Methods      The catalytic domain and non-catalytic domain cDNA of AaHIV from Agkistrodon acutus were synthesized and cloned into pET28a(+) vector

respectively. The recombinant plasmids were transferred into E. coli BL21(DE3). Expression products were finally purified by affinity chromatography. Kunming mice were randomly divided into 4 groups (n=6

4 weeks

20±2 g

male/female ratio=1∶1)

including a catal

ytic domain group

a non-catalytic domain group

an AaHIV group and a PBS group. After the third round of immunization

the antiserum was obtained. Titer was determined by ELISA and the protective effect of antiserum was analyzed by hemorrhagic activity test after neutralization of AaHIV.       Results      Both of the 2 recombinant fragments of AaHIV had immunogenicity. Neutralization test showed that as compared to the PBS group

the catalytic domain group and the non-catalytic domain group both showed significantly reduced subcutaneous hemorrhage (

P

0.05). The subcutaneous hemorrhage area of the AaHIV group was significantly different from that of the non-catalytic domain group (

P

0.05) but not from that of the catalytic domain group (

P

0.05).       Conclusion      The antiserum induced by the catalytic domain of AaHIV from Agkistrodon acutus can more effectively neutralize the hemorrhagic activity of AaHIV.