ABSTRACT
Citrus tristeza virus (CTV) was purified from a citrus sample by a modified protocol, and the yield was about 1 mg from 100 g citrus tissues. Polyclonal antibody was prepared by immunizing rabbits with the purified CTV preparation with a titer 1:25600 in indirect ELISA test. Eighteen hybridoma-cell lines secreting monoclonal antibodies (MAbs) against CTV were screened after the fusion of mouse myeloma cells (SP2/0) with spleen cells from BALB/c immunized with the virus preparation. Four hybridoma-cell lines were selected randomly for later analysis. The results indicated that the titers of ascetic fluids against these hybridoma cell lines ranged from 1:51200 to 1:204800 in indirect ELISA, and their isotypes and subclasses were IgG2a for 2G and 3H and IgG2b for IE and 4H. These four Mabs were used to detect CTV in citrus samples in different sources. Results showed that TAS-ELISA with polyclonal antibody as trapping antibody and monoclonal antibody as testing antibody had a higher specificity and sensitivity than PAS-ELISA. Four Mabs showed different intensities of serological reaction with different CTV isolates. However, much work remains for realizing the characteristics and the serological relationships among these isolates.