Immunogenicity of tetanus component in monovalent and combined vaccines

Abstract number: 1733_574

Janaszek-Seydlitz W., Bucholc B., Czajka U., Wiatrzyk A.

Objectives: Vaccination with combined vaccines is without any doubt beneficial, allowing for decreasing number of injections and costs connected with vaccination. However, there is a possibility that the interaction between components of combined vaccines may influence their immunogenicity and reactogenicity. The immunogenicity of tetanus component in monovalent tetanus toxoid adsorbed and combined vaccines DTP and DTP+IPV was evaluated on Balb/c mice.

Methods:Animals: Six weeks old Balb/c mice were immunised with tetanus toxoid adsorbed; DTP or DTP+IPV. Animals (10 mice in each group) were injected subcutaneously three times with dose 0.25 ml at 6 weeks intervals. Control was unvaccinated.

Enzyme-linked immunosorbent assay (ELISA): The antibody responses to tetanus toxoid in sera 14 days after the immunisation were determined using in house ELISA method. The level of antibodies was expressed in arbitrary units.

Production of IFN-g and IL-5: The levels of IFN-g and IL-5 were evaluated in supernatants of cell culture of splenocytes stimulated by non-adsorbed tetanus toxoid or PHA.

Results: Geometric mean titre for anti-tetanus antibodies evaluated 14 days after the immunisation in animals vaccinated with tetanus toxoid adsorbed was lower (2650.2 a.u./mL) than in animals vaccinated with DTP (3968.6 a.u./mL) or DTP+IPV (4070.7 a.u./mL). There was no statistical differences between groups of animals receiving only DTP or simultaneously DTP and IPV. The mean concentration of IFN-g in supernatants from specific stimulated cell cultures derived from animals vaccinated with tetanus toxoid was 720.45 pg/mL, from animals vaccinated with DTP – 2579.7 pg/mL and from animals vaccinated with DTP+IPV 1812.05 pg/mL.

The mean concentrations of IL-5 are about 20-times lower than concentration of IFN-g in cell cultures of splenocytes derived from all evaluated groups of animals.

Conclusions: Whole-cell pertussis component influences as adjuvant on tetanus component in combined vaccines. Simultaneously administrated IPV vaccine not influences on immunogenicity of tetanus component. Pertussis component significantly increases level of specific tetanus antibodies and production of IFN-g in cell cultures derived from vaccinated animals.