In vitro assessment of viral antigen content in inactivated aluminum hydroxide adjuvanted vaccines.

Antigen capture enzyme immunoassays (ELISA) were developed to assess the antigenic content of inactivated aluminum hydroxide (AH) adjuvanted porcine parvovirus, pseudorabies, and infectious bovine rhinotracheitis vaccines. Reference preparations of these viruses were constructed as a basis for comparison. Because AH-associated ELISA interference was largely circumvented, the need for isotopic or complex antigen-adjuvant desorption methods was eliminated. A 4-parameter logistic model related optical density to vaccine dilution. High correlation coefficients (r) were routinely achieved with commercial monovalent and polyvalent vaccines, and reference preparations. The procedure quantified antigen in both aqueous and AH-associated phases. The method may be generally applicable as a partial substitute for in vivo vaccine potency testing by allowing in vitro estimation of inactivated viral antigenic content in AH adjuvanted vaccines.