Abstract:
Bovine milk is an important source of proteins for human. But it can cause allergic reaction in some children. In the severe cases, it can lead to death rapidly. The milk major protein that causes allergy is casein (80% of the total milk protein) which composes of αs-, β- and κ-forms at 50%, 40% and 10%, respectively. Many chemical based methods have been developed to detect casein. However, these methods require expensive instruments and are not suitable for an on-site detection. On the contrary, immunological-based method, specifically a strip test, is more of interest due to its simplicity, inexpensive and ready to use for on-site application. Therefore, the objective of this research is to produce and screen for monoclonal antibodies suitable for casein detection. Conventional somatic cell fusions of splenocytes of six BALB/c mice immunized with mixed form of casein and P3X myeloma cell line were performed. In total, 60 monoclones which were divided into 7 groups based on their cross-reactivities to different forms of casein were obtained. Among these monoclones, 8 clones (CN1F4, CN3F4, CN5F4, CN10F4, CN11F4, CN12F4, CN16F4 and CN20F4) were selected for further studies because their monoclonal antibodies (MAb) reacted with the mixed form of casein and did not cross-react with other tested substances. MAb were produced and partially purified. Then, sensitivity of each MAb was analyzed by an indirect enzyme-linked immunosorbent assay and reported as 50% effective concentration (EC50) and limit of detection (LOD). The values of EC50 and LOD were found to be in the ranges of 0.09-0.86 µg/ml and 6.1-21.5 ng/ml, respectively. All MAbs obtained could also be used for further development of test kit because of their high sensitivity.