A Comparison between ELISA and CIEP for Measuring Antibody Titres against Aleutian Mink Disease Virus

Abstract

Introduction: Enzyme-linked immunosorbent assays (ELISA) is used for the identification of mink with low antibody titre against the Aleutian mink disease virus (AMDV) who can tolerate the infection. There is no published information on the merit of ELISA for measuring antibody titre. An ELISA was compared with the counterimmunoelectrophoresis (CIEP) for quantifying antibodies against AMDV. Materials and methods: In experiment 1 (EX1), 41 black mink were inoculated with various amounts of a local strain of AMDV and were euthanized on day 218 post-inoculation (pi). In experiment 2 (EX2), 262 black mink were inoculated with a single doses of the same virus and euthanized 16 to 71 weeks pi. Antibodies to AMDV were quantified by CIEP using 10 two-fold serial dilutions of plasma, and serum samples were tested by the ELISA. Total serum proteins, albumin and globulins were measured in EX1. Results and discussion: All mink were tested positive for AMDV infection by PCR in both experiments. There were moderate concordances between CIEP and ELISA results (Spearman correlation of 0.77 and 0.71 in EX1 and EX2, respectively). Each ELISA class spanned a wide range of antibody titres in both experiments. Antibody titres of lower than 32 were not associated with serum proteins while greater titers were positively associated with total serum proteins and globulins (P<0.01) and negatively associated with albumin and albumin:globulin ratio (P<0.01). Regressions of serum protein measurements on ELISA classes were linear and in the same directions as, although weaker than, those on CIEP. Conclusion: Although ELISA was not able to accurately measure anti-AMDV antibody titre, in the absence of any other practical method, it is a useful tool for ranking mink for anti-AMDV antibody titres.