Assessment of mumps virus-specific antibodies: Comparison of three different enzyme immunoassays and neutralization test

Introduction

We evaluated the application of a newly improved enzyme immunoassay (EIA) kit, Mumps IgG Seiken®, by comparing antibody responses to different EIA kits, and neutralization tests (NTs), using clinical samples.

Methods

Serum samples were collected before and 4–6 weeks after vaccination from 128 children who had no history of mumps or mumps vaccination. Using three different EIA kits, Mumps IgG Seiken®, a commercial kit from Enzygnost®, and an in-house kit, mumps-specific IgG antibodies were measured. Anti-mumps antibody responses between each of the EIA kits and NTs were evaluated.

Results

Before vaccination, all samples were seronegative, except for three serum samples measured by Mumps IgG Seiken®, which exhibited equivocal. The antibody-positivity rates and equivocal rates of Mumps IgG Seiken® post-vaccination (71.1 % and 23.4 %, respectively) were comparable to those of Enzygnost® (74.2 % and 19.5 %, respectively). However, antibody-positivity and equivocal rates were significantly higher and lower than those of in-house kit (51.6 % and 40.6 %, respectively) (p < 0.05). The concordance rates of the kit (68.7 %) were comparable to those of Enzygnost® (71.1 %) and higher than those of in-house-developed kit (58.6 %) (p < 0.05). The area under curve of the three EIA kits were 0.801, 0.804, and 0.859; however, the differences did not reach significance. Correlations of the values obtained using three EIA kits with NTs were 0.71, 0.61, and 0.78.

Conclusion

The newly approved Mumps IgG Seiken® showed good correlation with NTs and had lower equivocal rates compared to in-house kit, comparable to Enzygnost®. This kit may be clinically acceptable for the evaluation of vaccine immunogenicity.