Summary
African swine fever (ASF) is an acute hemorrhagic disease of domestic
pigs. The causative agent of ASF, ASF virus (ASFV), is a double-stranded
DNA virus, the sole member in the family Asfarviridae . The
non-structural protein pB602L of ASFV is a molecular chaperone of the
major capsid protein p72 and plays a key role in the icosahedral capsid
assembly. This protein has good antigenicity and is also a target for
developing diagnostic tools for ASF. To understand the molecular basis
for the antigenicity of pB602L, a procaryoticly expressed recombinant
pB602L protein was produced and applied to immunize mice for producing
monoclonal antibodies (mAbs). A total of eight mouse mAbs were obtained
and their binding epitopes were screened by Western blot against
overlapped polypeptides of pB602L. Three linear epitopes were identified
and designated Epitope 1
(366ANRERYNY373), Epitope 2
(415GPDAPGLSI423), and Epitope 3
(498EMLNVPDD505). Based on their
recognizing epitopes, the eight mAbs were placed to three groups: Group
1 (B2A1, B2F1 and B2D10), Group 2 (B2H10, B2B2, B2D8, and B2A3), and
Group 3 (B2E12), accordingly. mAbs B2A1, B2H10 and B2E12 were applied to
detect pB602L in ASFV infected porcine alveolar macrophages (PAM) and
pig tissues by indirect florescence assay (IFA), immunohistochemical
staining, and immunogold labeling for electron microscopy, respectively.
The results showed that pB602L was well detected with all the three mAbs
by immunohistochemical staining and immunoelectron microscopy; but only
B2H10 was suitable for detecting the protein in ASFV infected PAM cells
by IFA. Taken together, we developed eight anti-pB602L mouse mAbs
recognizing three linear epitopes in the protein, which provide
biological materials and molecular basis for the basic and applied
researches on ASFV.