Ching Ho Szeto1
1Wong Tai Sin Hospital, Hong Kong
Delta virus is a newly widespread mutant that shows increase resistance to most vaccine due primarily to the mutation of spike protein. Epidemiological study, wearing mask, limitation of gathering, social distancing and city closure may help. Herd immunity can be achieved by more than 70% population being vaccinated. However, the virus mutates again during the vaccine production, reducing the effectiveness of vaccine. So preventing the receptor binding by neutralizing antibody is fruitful to reduce the mortality of critically ill patients. However, convalescent serum is limited in supply and is not in a concentrated form. To manufacture SARS‐CoV‐2 neutralizing mAbs, we first isolate antibodies from convalescent patients, immunized animals or phage‐displayed human antibody libraries. Then they are amplified using germline genes. Mass industrial production through stable cell lines can be employed in the treatment. Hollow fiber bioreactor allows the production of high concentration of antibodies. The hybridoma cells are grown in fresh medium, which is changed regularly to reduce the accumulation of toxic by‐products. By centrifugation, ion exchange chromatography column, and electrophoresis, purified antibodies can be obtained. Humanized mAbs have the advantages of being less immunogenic, more effective and have a longer half‐life than chimeric antibodies (11‐24 days). As COVID attacks not only the lung but also the neurological system, this makes antibody‐conjugated nanoparticles particularly useful as it can penetrate into various tissue better, e.g. photothermal nanoparticles conjugated with neutralizing antibodies can inactivate SARS‐CoV‐2 on shining light of wavelength 500‐850nm. The traditional hybridoma techniques in mouse also work.