Biology subjects

Yewdell, J.

Publications and source records attributed to Yewdell, J..

3 recordsLinked to original sources

bioRxiv2023

Omicron Spike confers enhanced infectivity and interferon resistance to SARS-CoV-2 in human nasal tissue

Omicron emerged following COVID-19 vaccination campaigns, displaced previous SARS-CoV-2 variants of concern worldwide, and gave rise to lineages that continue to spread. Here, we show that Omicron exhibits increased infectivity in primary adult upper airway tissue relative to Delta. Using recombinant forms of SARS-CoV-2 and nasal epithelial cells cultured at the liquid-air interface, enhanced infectivity maps to the step of cellular entry and evolved recently through mutations unique to Omicron Spike. Unlike earlier variants of SARS-CoV-2, Omicron enters nasal cells independently of serine transmembrane proteases and instead relies upon metalloproteinases to catalyze membrane fusion. This entry pathway unlocked by Omicron Spike enables evasion of constitutive and interferon-induced antiviral factors that restrict SARS-CoV-2 entry following attachment. Therefore, the increased transmissibility exhibited by Omicron in humans may be attributed not only to its evasion of vaccine-elicited adaptive immunity, but also to its superior invasion of nasal epithelia and resistance to the cell-intrinsic barriers present therein.

microbiology↗

bioRxiv2022

Paradox Found: Global Accounting of Lymphocyte Protein Synthesis

Rapid lymphocyte cell division places enormous demands on the protein synthesis machinery. Flow cytometric measurement of puromycylated ribosome-associated nascent chains after treating cells or mice with translation initiation inhibitors reveals that ribosomes in resting lymphocytes in vitro and in vivo elongate at typical rates for mammalian cells. Intriguingly, elongation rates can be increased up to 30% by activation in vivo or fever temperature in vitro. Resting and activated lymphocytes possess abundant monosome populations, most of which actively translate in vivo, while in vitro, nearly all can be stalled prior to activation. Quantitating lymphocyte protein mass and ribosome count reveals a paradoxically high ratio of cellular protein to ribosomes insufficient to support their rapid in vivo division, suggesting that the activated lymphocyte proteome in vivo may be generated in an unusual manner. Our findings demonstrate the importance of a global understanding of protein synthesis in lymphocytes and other rapidly dividing immune cells.

immunology↗

bioRxiv2018

Influenza A Virus Negative Strand RNA is Translated for CD8+ T Cell Immunosurveillance

To probe the limits of CD8+ T cell immunosurveillance, we inserted the model peptide SIINFEKL into influenza A virus (IAV) negative strand gene segments. Although IAV genomic RNA is widely considered as non-coding, there is a conserved, relatively long open reading frame present in the genomic strand of segment eight, encoding a potential protein termed NEG8. The biosynthesis of NEG8 from IAV has yet to be demonstrated. While we failed to detect NEG8 protein expression in IAV infected cells, cell surface Kb-SIINFEKL complexes are generated when SIINFEKL is genetically appended to the predicted COOH-terminus of NEG8, as shown by activation of OT-I T cells in vitro and in vivo. Moreover, recombinant IAV encoding SIINFEKL embedded in the negative strand of the NA-stalk coding sequence also activates OT-I T cells in vivo. Together, our findings demonstrate both the translation of sequences on the negative strand of a single stranded RNA virus and its relevance anti-viral immunosurveillance.\n\nSignificanceEvery gene encodes complementary information on the opposite strand that can potentially be used for immunosurveillance. In this study, we show that the influenza A virus \"non-coding\" strand translated into polypeptides during a viral infection of either cultured cells or mice that can be recognized by CD8+ T cells. Our findings raise the possibility that influenza virus uses its negative strand to generate proteins useful to the virus. More generally, it adds to a growing literature showing that immunosurveillance extends to gene sequences generally thought not to be converted into proteins. The relevance of translating this \"dark\" information extends from viral immunity to cancer immunotherapy and autoimmunity.

immunology↗