Reynoso, G. | bioRxiv Science

bioRxiv2023

Chikungunya virus infection disrupts lymph node lymphatic endothelial cell composition and function via MARCO

Infection with chikungunya virus (CHIKV) causes disruption of draining lymph node (dLN) organization, including paracortical relocalization of B cells, loss of the B cell-T cell border, and lymphocyte depletion that is associated with infiltration of the LN with inflammatory myeloid cells. Here, we find that during the first 24 h of infection, CHIKV RNA accumulates in MARCO-expressing lymphatic endothelial cells (LECs) in both the floor and medullary LN sinuses. The accumulation of viral RNA in the LN was associated with a switch to an antiviral and inflammatory gene expression program across LN stromal cells, and this inflammatory response, including recruitment of myeloid cells to the LN, was accelerated by CHIKV-MARCO interactions. As CHIKV infection progressed, both floor and medullary LECs diminished in number, suggesting further functional impairment of the LN by infection. Consistent with this idea, we find that antigen acquisition by LECs, a key function of LN LECs during infection and immunization, was reduced during pathogenic CHIKV infection.

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↗