Characterization of performance of three commercial monoclonal antibodies in detection of spike protein in SARS-CoV-2

Abstract

The study aimed at characterizing the Performance of three commercial monoclonal antibodies in detection of spike protein in SARS-CoV-2. This was looking at avidity and specificity of the monoclonal antibodies which would be used to compare the performance of the three monoclonal antibodies. This assay was based on a principle of dilutions where we looked at the best performing monoclonal antibody under minimum concentrations and the present conditions in the country at the moment. These results were used to inform development of an in-house Elisa for detection of COVID19 among the populations in the country. A research purposed Elisa kit, the commercial monoclonal antibodies and a commercially available SARS-CoV-2 Spike protein were commercially procured and used for this study. The study was carried out from at Makerere University, College of Health Sciences Immunology laboratory. The primary outcome of this study was to have a successful optimization which included coming up with a working concentration of the antigen being coated and to come up with the right dilutions of the antibodies to be used. The secondary outcome was to come up with the best performing antibody and Spike protein readily available on market under the local Ugandan conditions for development of an in-house Elisa kit. Discussion and Conclusion: From the results, it was seen that Invitrogen and genescript monoclonal antibodies gave better performance in terms of specificity and avidity index values and therefore can be seen as the best candidates in development of an in-house Elisa kit for detection of SARS-CoV-2. In conclusion, basing on the results and discussion as seen above, we decided that the Invitrogen and genecript monoclonal antibodies would be used as the best candidates in development of an in-house Elisa kit in dilutions ratios of 1:200 for detection of SARS-CoV-2. The spike protein used was also concluded that it would be used at a concentration of 200ng per well when coating the plates to be used to detect or test for SARS-CoV-2 using an in-house Elisa while PBS also emerged as a good candidate to be used as a substitute for the antigen coating buffer.