ABSTRACT
Generated by the immune system post-infection or through vaccination, the effectiveness of antibodies against emerging SARS-CoV-2 variants is crucial for protecting individuals from the COVID-19 pandemic. Herein, a platform for the multiplexed evaluation of SARS-CoV-2 neutralizing antibodies against various variants was designed on the basis of near-infrared (NIR) surface enhanced fluorescence by nano-plasmonic gold chip (pGOLD). Antibody level across variants (Wild-type, Alpha, Beta, Delta, Omicron) was confirmed by the sera from recovered-individuals who were unvaccinated and had infected with Wild-type, Delta, Omicron variants. However, the neutralizing activity against Omicron variant was markedly decreased for individuals infected by Wild-type (~ 5.6-fold) and Delta variant (~ 19.1-fold). To the opposite, neutralizing antibody from individuals recovered from Omicron variant infection showed weak binding strength against non-Omicron variants. Antibody evolution over time was studied with individuals 196-530 days post Wild-type infection. Decreasing IgG antibody titer accompanied by increasing IgG binding avidity with elongated post-infection period were observed for the sera from Wild-type recovered-individuals with different post-infection times, suggesting that after the primary infection, a great number of antibodies were generated and then gradually decreased, while the antibody matured over time. By comparing the IgG level of individuals vaccinated for 27-51 days with individual post-infection, we found that ca. 1 month after two doses of vaccination, the antibody level was comparable to that of 500 days post-infection, and vaccination could enhance IgG avidity more efficiently. This work demonstrated a platform for the multiplexed, high-throughput and rapid screening of acquired immunity against SARS-CoV-2 variants, providing a new approach for the analysis of vaccine effectiveness, immunity against emerging variants, and related serological study.
ABSTRACT
Many scientific research papers report that jet-like flow during speech is a potent route for viral transmission in the COVID-19 pandemic. Droplet emission occurs during breaking, speaking, singing, coughing and sneezing, which could be affected by the shear-thinning rheology of the liquid. Here we test the viscosity of simple liquid system in many-body dissipative particle dynamics model under different driven forces, which illustrates that the simple liquid system interestingly has shear-thinning property. Based on this, we simulate the process of jet-like flow and capture the rupture of liquid cylinder and the process of drop generation, which implies the jet-induced liquid pinchoff and drop generation can be regulated by initial driven force and its temperature. The results show that larger pressure pulse could generate longer liquid cylinder and larger drops, as well as at lower force frequency. This work can provide an insight in liquid jet-like flow with shear-thining property and yield a better understanding of virus spreading via salivary droplets. [ FROM AUTHOR] Copyright of Modern Physics Letters B is the property of World Scientific Publishing Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)