ABSTRACT
Mutations of the coronavirus responsible for coronavirus disease 2019 (COVID-19) could impede drug development and reduce the efficacy of COVID-19 vaccines. Here, we developed a multiplexed Spike-ACE2 Inhibitor Screening (mSAIS) assay that can measure the neutralizing effect of antibodies across numerous variants of the coronaviruss Spike (S) protein simultaneously. By screening purified antibodies and serum from convalescent COVID-19 patients and vaccinees against 72 S variants with the mSAIS assay, we identified new S mutations that are sensitive and resistant to neutralization. Serum from both infected and vaccinated groups with a high titer of neutralizing antibodies (NAbs) displayed a broader capacity to neutralize S variants than serum with low titer NAbs. These data were validated using serum from a large vaccinated cohort (n=104) with a tiled S peptide microarray. In addition, similar results were obtained using a SARS-CoV-2 pseudovirus neutralization assay specific for wild-type S and four prevalent S variants (D614G, B.1.1.7, B.1.351, P.1), thus demonstrating that high antibody diversity is associated with high NAb titers. Our results demonstrate the utility of the mSAIS platform in screening NAbs. Moreover, we show that heterogeneous antibody populations provide a more protective effect against S variants, which may help direct COVID-19 vaccine and drug development. HighlightsO_LIDeveloped a high throughput assay to screen the neutralizing effect of antibodies across multiple SARS-CoV-2 Spike variants simultaneously. C_LIO_LICharacterized the heterogeneity of neutralizing antibodies produced in response to COVID-19 infection and vaccination. C_LIO_LIDemonstrated the capacity of Spike variants neutralization is associated with the diversity of anti-Spike antibodies. C_LI
ABSTRACT
Objective:To study the expression of human leukocyte antigen G (HLA-G) during human T lymphocytic leukemia virus type 1 (HTLV-1) infection, and to investigate the function and mechanism of HLA-G in HTLV-1 immune escape.Methods:HeLa and THP-1 cells were infected by MT2, a stable HTLV-1 infected cell line. Expression of HLA-G isomers at mRNA and protein levels was detected by qRT-PCR and Western blot, respectively. Flow cytometry was used to detect the expression of HLA-G1. Moreover, transfection and siRNA gene were respectively used to up-regulate and silence HLA-G expression in HeLa cells to observe the changes in the expression of HTLV-1-featured protein Tax on protein level after HTLV-1 infection.Results:HTLV-1 infection could induce differential expression of HLA-G isomers, mainly HLA-G1 and HLA-G5, in HeLa and THP-1 cells. HLA-G expression at both mRNA and protein levels was significantly up-regulated 24 h after HTLV-1 infection. Moreover, the expression of HTLV-1 protein Tax was significantly enhanced in HTLV-1-infected HeLa cells overexpressing HLA-G. An opposite result was obtained when the HLA-G gene in HeLa cells was silenced by siRNA.Conclusions:The immune-tolerant molecule HLA-G was significantly increased in HTLV-1-infected cells, thereby promoting the expression of HTLV-1 viral protein, which led to persistent viral infection.
