Cutting edge: FcR-like 5 on innate B cells is targeted by a poxvirus MHC class I-like immunoevasin.
Under selective pressure from host immunity, viruses have retained genes encoding immunoevasins, molecules interfering with host viral recognition and clearance. Due to their binding specificities, immunoevasins can be exploited as affinity labels to identify host-encoded molecules of previously unsuspected importance in defense against the relevant class of virus. We previously described an orthopoxvirus MHC class I-like protein (OMCP) that binds with high affinity to the activating receptor NKG2D on NK and T cell subsets, implicating NKG2D in antiorthopoxvirus immunity. In this study, we report that OMCP also binds in an NKG2D-independent manner to B cells and monocytes/macrophages. We identify murine FcR-like 5 (FCRL5), an orphan immunoregulatory protein highly expressed by innate B lymphocytes, as a specific receptor for OMCP. The three N-terminal Ig domains of FCRL5 are required for OMCP binding. The targeting of FCRL5 by an orthopoxvirus immunoevasin strongly implicates it in contributing to host defense against zoonotic orthopoxviruses.
Division of Pediatric Rheumatology, Department of Pediatrics, Washington University School of Medicine, St Louis, MO 63110, USA.
Jessica A
JA
Campbell
Randall S
RS
Davis
Lauren M
LM
Lilly
Daved H
DH
Fremont
Anthony R
AR
French
Leonidas N
LN
Carayannopoulos
D000818:Animals; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D002460:Cell Line; D045744:Cell Line, Tumor; D018390:Gene Targeting; D015395:Histocompatibility Antigens Class I / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D057131:Immune Evasion / Q000276:immunology*; D007113:Immunity, Innate; D008024:Ligands; D008264:Macrophages / Q000276:immunology / Q000378:metabolism / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009000:Monocytes / Q000276:immunology / Q000378:metabolism / Q000821:virology; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000378:metabolism*; D018155:Orthopoxvirus / Q000276:immunology* / Q000472:pathogenicity; D011485:Protein Binding / Q000276:immunology; D011961:Receptors, Fc / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism / Q000502:physiology*
C515879:FcRH3 protein, mouse; D015395:Histocompatibility Antigens Class I; C527086:Klrk1 protein, mouse; D008024:Ligands; D055655:NK Cell Lectin-Like Receptor Subfamily K; D011961:Receptors, Fc; D014764:Viral Proteins