Comparative Study on the Adsorption Rate and Antibody Level of Bulk Purified Diptheria Toxoid on Chemical Adjuvants: Aluminium Phosphate, In Situ Gel and Calcium Phosphates

Vaccines often contain preservatives, adjuvants, in addition to pathogen specific immunogen. It contain inactivated bacterial toxin. Vaccines also contain preservative that prevent bacterial or fungal contamination (e.g. thiomersal); adjuvants that enhance antigen specific immune responses (e.g. aluminium and calcium salts). Although alum is the most commonly used vaccine adjuvant, it has some limitations for use with the next generation recombinant antigens. In the present study the use of alternative adjuvant formulation with calcium phosphate and in situ was explored. In this study the stability of old gel along with new gel was checked and showed 100% adsorption rate of old AlPO4 gel which was same as that of new gel. In situ and calcium phosphate were also used as an alternative adjuvants. Calcium phosphate gel showed the increased efficacy of the DT group of vaccine and did not show any adverse effects. The study using in situ gel yield lesser aluminum content but it shows greater adsorption rate. Finally the adsorption rate and antibody level of the gels were compared. Calcium phosphate shows higher density by comparing the adsorption rate with aluminium phosphate gel. Calcium phosphate gel shows less percentage of adsorption rate but the antibody levels were greater. Comparison of aluminium phosphate with in situ gel shows the same result.