Research progress in optimization of therapeutic effect of antibodies against flavivirus / 中华微生物学和免疫学杂志

Flaviviruses are a class of positive-strand RNA viruses mainly transmitted by arthropods, which can cause high mortality and morbidity worldwide. At present, there is no specific therapy. Therapeutic antibodies bring hope for the treatment of flavivirus infection, but the antibody-dependent enhancement (ADE) effect induced by flavivirus infection can lead to disease progression. The ideal therapeutic antibodies against flaviviruses should not only treat flavivirus infection, but also avoid the harm caused by ADE. Therefore, researchers have optimized some of the antibodies to seek the best therapeutic antibodies. This review briefly described the research progress and mechanism of therapeutic antibodies against flaviviruses as well as some strategies to reduce the ADE effect induced by the therapeutic antibodies.

SARS-CoV-2 membrane protein is incompetent at inducing antibody-dependent enhancement though Fc receptor pathway / 中华微生物学和免疫学杂志

Objective:To investigate the immune characteristics of SARS-CoV-2 membrane (M) protein, especially the possibility of inducing antibody-dependent enhancement effect (ADE).Methods:Full-length SARS-CoV-2 M protein was prepared by prokaryotic expression system and purified. BALB/c mice were immunized subcutaneously three times (on day 1, day 14 and day 21) by purified M protein. Serum samples were collected before immunization and after each immunization. The specificity of immune sera against M protein was identified by Western blot, and the antibody titers were detected by ELISA and neutralization test. In the presence of anti-M protein serum, the proliferation of SARS-CoV-2 in dendritic cells, nature killer cells, T and B cells was detected in vitro. Results:The immune sera from BALB/c mice immunized with purified full-length M protein of SARS-CoV-2 specifically recognized viral M protein. The titer of anti-whole virus antibody in immune sera was about 1∶400, but the antibody could not neutralize live virus. Moreover, the antibody could not help the virus to infect and proliferate in the various types of immune cells with Fc receptor (FcR).Conclusions:Non-neutralizing antibody induced by M protein could not cause ADE through FcR pathway.