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A distinct subset of human NK cells expressing HLA‐DR expand in response to IL‐2 and can aid immune responses to BCG
Author(s) -
Evans J. Henry,
Horowitz Amir,
Mehrabi Maryam,
Wise Emma L.,
Pease James E.,
Riley Eleanor M.,
Davis Daniel M.
Publication year - 2011
Publication title -
european journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 201
eISSN - 1521-4141
pISSN - 0014-2980
DOI - 10.1002/eji.201041180
Subject(s) - biology , immunology , immune system , cxcr3 , interleukin 12 , interleukin 21 , chemokine , degranulation , human leukocyte antigen , peripheral blood mononuclear cell , cytotoxic t cell , chemokine receptor , antigen , t cell , receptor , in vitro , biochemistry
Abstract Subsets of NK cells can have distinct functions. Here, we report that >25% of human peripheral blood NK cells express HLA‐DR after culture with IL‐2. This can be driven by an expansion of a small subset of NK cells expressing HLA‐DR, in contrast to previous assumptions that HLA‐DR is upregulated on previously negative cells. HLA‐DR‐expressing NK cells showed enhanced degranulation to susceptible target cells and expressed chemokine receptor CXCR3, which facilitated their enrichment following exposure to CXCL11/I‐TAC. Suggesting HLA‐DR‐expressing NK cells have an important role in an immune response, stimulation of PBMCs with Mycobacterium bovis BCG (BCG) triggered expansion of this subset. Importantly, the magnitude of an individual's NK cell IFN‐γ response triggered by BCG was associated with the initial frequency of HLA‐DR‐expressing NK cells in PBMCs. More directly indicating the importance of HLA‐DR‐expressing NK cells, enriching the frequency of this subset in PBMCs substantially augmented the IFN‐γ response to BCG. Thus, HLA‐DR expression marks a distinct subset of NK cells, present at low frequency in circulating blood but readily expanded by IL‐2, that can play an important role during immune responses to BCG.