NK cells bearing inhibitory receptor Ly49G2 preferentially respond to and efficiently control murine cytomegalovirus (MCMV) in MA/My and C57L mice with Dk. Thus the role of Ly49G2 and Dk in virus control is under study. One hypothesis to explain the necessity of Ly49G2 and Dk is “missing self” recognition—release of inhibition due to downregulation of MHC I—by Ly49G2 of Dk during infection. To confirm Ly49G2 binding to Dk, we generated reporter cells expressing chimeric Ly49G2. We also performed licensing and cytotoxicity assays to assess Ly49G2+ NK cell licensing and inhibition of Dk, thus confirming Dk as the cognate ligand of Ly49G2. Next we examined Ly49G2 recognition of Dk on infected cells. Recent data has shown MCMV immunoevasin gp34 bound to MHC I stabilizes interactions between inhibitory receptors and MHC I, including the BALB allele of Ly49G2. However as BALB.K mice with Dk have 3-fold higher MCMV titers than MA/My or C57L mice with Dk, we examined the role of gp34 in Ly49G2c57l recognition of Dk. We show preferential association of gp34 to Dk, not Kk. Further, binding assays also confirm gp34 stabilization of Ly49G2mamy binding to Dk on infected cells. As cis Dk expression with Ly49G2 may impact trans binding, we are examining the role of cis binding of Dk. Additionally, signaling may be impacted by gp34, causing “missing self” recognition by Ly49G2. As such, Ly49G2 phosphorylation is being assessed, as well as phosphorylation of downstream inhibitory molecules.
- Copyright © 2013 by The American Association of Immunologists, Inc.