PMC:3463543 / 22172-24515 JSONTXT

{"project":"2_test","denotations":[{"id":"23056454-11874811-92972565","span":{"begin":211,"end":213},"obj":"11874811"},{"id":"23056454-2681268-92972566","span":{"begin":217,"end":219},"obj":"2681268"},{"id":"23056454-18359825-92972567","span":{"begin":288,"end":290},"obj":"18359825"},{"id":"23056454-18359825-92972568","span":{"begin":1265,"end":1267},"obj":"18359825"},{"id":"23056454-13713229-92972569","span":{"begin":2078,"end":2079},"obj":"13713229"},{"id":"23056454-13904777-92972570","span":{"begin":2083,"end":2085},"obj":"13904777"}],"text":"Relationship in Mucus\nRespiratory tract mucus is a complicated combination of water (∼95%), inorganic salts (∼1%), and various macromolecular organic compounds including glycoproteins (i.e., mucins) and lipids [20], [21], [32]. It has been shown to be protective for IAV at low RH [33], [34]. However, the relationship between viability of IAV in mucus and RH is still not completely clear.\nWe initially conducted experiments with mucin extracts from porcine stomach (Type II, Sigma-Aldrich). Results indicated that IAV infection was blocked, probably by the bound sialic acid on the mucin. Similarly, glycans on human mucus could prevent IAV attachment to the cell in the TCID50 assay. However, such an effect was not significant according to our experiment. The titer of IAV spiked in the human mucus specimen was 5.1±2.6×107 TCID50 ml−1 after being kept on ice for 2 h, with a spiking titer of 1.78×108 TCID50 ml−1. In addition, reporting results in mucus samples as the ratio of the recovered viability after incubation at a specific RH over the initial viability, both tested in mucus, should control for any potential blocking effect due to glycans on mucus. Therefore, results reported here reflect the effect of RH.\nIn accordance with the literature [33], [34], we found higher viabilities at low RHs (\u003c50%). The finding that IAV survived best at ∼100% RH, a condition which has not been examined previously, helps complete the understanding of the response of the virus to varying RH. The relationship in mucus bears some similarity to that in media with salts plus proteins, particularly DMEM+FCS (i.e., higher viabilities at ∼100% RH or RH\u003c50% and much lower ones at medium RH ranging from ∼50% to 84%). However, viability was much more sensitive to RH in mucus than in synthetic model media. A small change in RH from 48% to 52% reduced the viability 10-fold, and viability at ∼84% RH was \u003e500 times lower than at 48% RH. For comparison, in model media, viabilities varied by only an order of magnitude over the same RH range, which is consistent with past studies [8], [13]. Thus, RH might have a greater effect on IAV’s survival in mucus than has been demonstrated in past studies with synthetic media. These results underscore the potential impact of RH on the virus’ survival in its natural aerosol carrier during transmission."}