A method for screening CDV microneutralization activity in microvolume samples.

OBJECTIVE: This study aims to establish a screening method for canine distemper virus (CDV) microneutralizing activity suitable for microvolume samples.

METHODS: This method is based on the Indirect immunofluorescence assay (IFA) established on Vero-slam cells. First, by comparing the sensitivities of CDV neutralizing monoclonal antibody (1C42H11) and NP protein monoclonal antibody (CDV-NP) in IFA experiments, CDV-NP was selected as the primary antibody. Then, by detecting the infection rates of multi-concentrations of CDV neutralized with water, the minimum CDV concentration with an infection rate greater than 90% was defined as the minimum stable infection concentration, which was used as the neutralizing solution for this method. Finally, the CDV-positive neutralizing serum (neutralizing titer 1:708) was diluted into multiple dilution groups as test samples, and then neutralized in equal volumes with the neutralizing solution to detect the neutralizing activity detection rates of each dilution group and the lowest detection limit of this method.

RESULTS: The results showed that the neutralizing activity of serum with a CDV neutralizing titer of 1:708 diluted 212 times was the lowest limit of detection, and the detection rate of microneutralizing activity was 63.54 ± 4.774%.

CONCLUSION: This study established an economical, stable, and easy-to-operate CDV microneutralizing activity high-throughput screening method, laying a methodological foundation for the development of native CDV neutralizing antibodies based on single B cells.