A Rapid and Cost-Effective Method for the Purification of Streptococcus pneumoniae Antiserum Using Tangential Flow Filtration Method

Antibodies are important agents in the laboratory diagnosis of various microorganisms such as Streptococcus pneumoniae. In this study, we prepared and purified IgG antibody against Streptococcus pneumoniae using novel methods to be used in ELISA and agglutination diagnostic kits. First, Streptococcus pneumoniae was cultured, harvested, and inactivated. Then, bacteria were injected into four mature New Zealand white rabbits, and antisera were developed. Afterward, immunoglobulins were purified using ammonium sulfate precipitation, diafilteration using Tangential Flow Filtration, and ion-exchange chromatography. The purified antibody was then biotinylated and used in ELISA. Gel electrophoresis results showed that the antibody was highly pure. Agglutination test on the primary antigen and clinical samples was four-plus. ELISA results showed that the sensitivity and specificity of the test were 95% and 100%, respectively. Results indicated that our fast method was suitable for anti-Streptococcus pneumoniae IgG purification. Repetitive qualitative and quantitative experiments confirmed high purity of the immunoglobulin. Thus, it could be a suitable candidate to be used in laboratory diagnostic kits.