Specific humoral immunity after immunization with vaccine contained Leningrad-3 (L-3) mumps virus strain of different potency

Abstract

Aim. The persistence of the specific antibodies and the kinetics of the antibody neutralizing activity level and spectrum were studied in two groups of healthy young adults after the immunization with two different vaccine lots characterized with the different vaccine potency were studied for 3 years.Materials and methods. Antibodies were measured by enzyme immunoassay (EIA) and by plaque reduction neutralization (PRN) assay using the L-3 vaccine mumps virus (MuV) and five more geterologous MuV strains of genotypes A, B, C, D and H as the targets in 3-year follow-up serum samples (n=60) of once-vaccinated volunteers.Results. Maximal of the specific antibodies functional activity according to the avidity index as well as to the neutralizing activity level against 6 used in the investigation MuV strains was registered on month 12th till 18th after vaccination in both groups of volunteers. Interestingly the specific IgG levels registered by EIA were going already down from month 12th. It was a waning immunity tendency, in general, over time in both groups of volunteers. In the current investigation two vaccines lots contained significantly different MuV titer in one dose (2, 76-fold difference, U-test p>0,005) induced the specific humoral immunity with no statistical differences in the measured parameters in 60 once vaccinated volunteers.Conclusion. The current study results make it possible to suggest controlling or limiting the maximum permissible level of vaccine potency, as no more. Such limitation could reduce the risk of the post vaccination reaction and of vaccine virus horizontal transmission. At the same time the optimal vaccine potency bound will make vaccine production more economical.

Keywords

• mumps vaccine potency
• specific antibodies neutralizing activity and avidity kinetics