ABSTRACT
We report that natural killer receptors (NKR) for major histocompatibility complex (MHC) class I molecules (MHC-NKR), the inhibitory killer immunoglobulin-like receptors (KIR), and the CD94/NKG2A receptor are present on a small proportion of CD8 T cells in cord blood. On average, 1.67% of CD8 T cells in cord blood express KIR, and 0.74% expresses NKG2A, approximately fivefold less than in adult blood. CD8 T cells expressing MHC-NKR were present at similar levels in cord blood from preterm and term infants, and it is important that their presence was independent of placental pathology or infection. Cord blood CD8 T cells expressing MHC-NKR were relatively homogeneous and entirely CD27+, mostly CC chemokine receptor 7- and granzyme B-, with a majority being CD45RA+ and with no evidence for a skewed distribution of T cell receptor-Vbeta when tested in KIR+ cells. This contrasted with adult blood, which was more heterogeneous, and where a majority of CD8 T cells expressing MHC-NKR was CD27- and granzyme B+. Functional studies revealed that cord blood KIR+ CD8 T cells were as capable as KIR- CD8 T cells in their ability to proliferate in response to CD3 ligation, yet it is interesting that they were more capable than KIR- CD8 T cells in their ability to secrete interferon-gamma. These data suggest that cord blood CD8 T cells expressing MHC-NKR are a unique subset of cells, distinct from those in adult blood, and may represent a less-differentiated population.
Subject(s)
Antigens, CD/analysis , CD8-Positive T-Lymphocytes/immunology , Fetal Blood/cytology , Receptors, Immunologic/analysis , T-Lymphocyte Subsets/immunology , Adult , Age Factors , CD8-Positive T-Lymphocytes/chemistry , CD8-Positive T-Lymphocytes/metabolism , Fetal Blood/immunology , Granzymes , HLA Antigens/analysis , Humans , Immunophenotyping , Infant, Newborn , Interferon-gamma/metabolism , Leukocyte Common Antigens/analysis , Lymphocyte Activation , NK Cell Lectin-Like Receptor Subfamily C , Receptors, Antigen, T-Cell, alpha-beta/analysis , Receptors, KIR , Receptors, Natural Killer Cell , Serine Endopeptidases/analysis , T-Lymphocyte Subsets/chemistry , T-Lymphocyte Subsets/metabolism , Tumor Necrosis Factor Receptor Superfamily, Member 7/analysisABSTRACT
This study reports an economical adaptation of the RosetteSep procedure for enrichment of NK cells designed for whole blood and its use with liquid nitrogen stored peripheral blood mononuclear cells (PBMC). Combining 45x10(6) PBMC with 45x10(8) Alsevers' stored red blood cells (RBC) in 1 ml requires 50 microl of RosetteSep bifunctional antibody cocktail and provides NK cells of 99% purity with average yields of 43%.
