Safety and immunogenicity study of nanoparticle aluminium hydroxide adjuvanted diphtheria toxoid vaccine

Background and Aim : In recent years, significant advances in nanoadjuvant technology have been made in the field of vaccines formulation. Nanoadjuvant provides a suitable opportunity for the production of a new generation of vaccines with desirable properties. The purpose of this study is to evaluate the safety and immunogenicity of nanoadjuvant aluminium hydroxide using diphtheria toxoid protein as an antigen model administered twice with ۲ weeks interval in SPF Balb/c mice.Methods : Briefly, five groups of ۱۰ Balb/c mice free of any pathogens (SPF) were used. Three groups of mice were immunized with diphtheria toxoid vaccine nano adjuvanted aluminium hydroxide, one group as negative control was received normal saline only and the other group was positive control with diphtheria toxoid vaccine formulated with standard microparticle aluminium hydroxide adjuvant. PBMC cells and serum preparation were performed. The cellular immune responses were evaluated by identifying the population of CD۴+, CD۸+ and CD۳+ T-cells using flow cytometer. Results : The results of this study showed that vaccinated mice with diphtheria vaccine adjuvanted with nanoparticle aluminium hydroxide gel induce a high level of specific total IgG antibody compared to groups receiving diphtheria vaccines formulated with microparticle aluminium hydroxide adjuvant and control groups. The results of this study showed that two weeks later, vaccinated groups had a higher expression of T lymphocytes than the control group. The ratio of CD۴+ lymphocytes to CD۸+ lymphocytes in groups vaccinated by diphtheria toxoid vaccine was significantly higher than the control group. The present study showed that the immune system may be associated with increased cellular immunity, which can be interpreted as T lymphocyte proliferation and increased CD۴+ to CD۸+ ratio.Conclusion : In conclusion, the present study revealed that the cellular immune response in the toxoid formulated with the nano-adjuvant of aluminium hydroxide precursor is far greater than its macromolecular form, and can enhance both Th۱ as well as Th۲ immune responses.

Keywords:

Aluminium hydroxide , Nanoadjuvant , Immunogenicity , diphtheria toxoid