Editors' ChoiceImmunology

Endogenous Retroviruses Trigger B Cells

Sci. Signal.  23 Dec 2014:
Vol. 7, Issue 357, pp. ec359
DOI: 10.1126/scisignal.aaa5284

Scattered across our genome are endogenous retroviruses (ERVs), ancient “footprints” of previous viral infections. Scientists do not fully understand their functions, but Zeng et al. now report a role for ERVs in mobilizing a particular type of B cell–driven immune response in mice [T cell–independent (TID)], which is usually mounted in response to viral capsids or bacterial polysaccharides (see the Perspective by Grasset and Cerutti). Immunizing mice with a model TID antigen elicited an increase in ERV RNA and DNA in the cytoplasm of B cells. Innate immune receptors that recognize cytoplasmic nucleotides then triggered signaling cascades that resulted in the production of immunoglobulin M.

M. Zeng, Z. Hu, X. Shi, X. Li, X. Zhan, X.-D. Li, J. Wang, J. H. Choi, K.-w. Wang, T. Purrington, M. Tang, M. Fina, R. J. DeBerardinis, E. M. Y. Moresco, G. Pedersen, G. M. McInerney, G. B. Karlsson Hedestam, Z. J. Chen, B. Beutler, MAVS, cGAS, and endogenous retroviruses in T-independent B cell responses. Science 346, 1486–1492 (2014). [Abstract] [Full Text]

E. K. Grasset, A. Cerutti, Retroviral help for B cells. Science 346, 1454–1455 (2014). [Abstract] [Full Text]