Immunophenotypic characterization of normal blood CD56+lo versus CD56+hi NK-cell subsets and its impact on the understanding of their tissue distribution and functional properties.
In the present study we have compared the immunophenotypic characteristics of the CD56+lo and CD56+hi NK-cell subsets in a group of normal healthy adults. Our results show that CD56+hi NK-cells display greater light-scatter properties than CD56+lo NK-cells at the same time they have higher levels of CD25 and CD122 IL-2 chains, together with a higher reactivity for HLA-DR and CD45RO and lower levels of CD45RA, supporting that, as opposed to the majority of the CD56+lo population, CD56+hi NK-cells might correspond to a subset of activated circulating NK-lymphocytes. Higher expression of the CD2 and CD7 costimulatory molecules found for the CD56+hi NK-cells would support their greater ability to respond to various stimuli. In addition, CD56+hi NK-cells expressed higher levels of several adhesion molecules such as CD2, CD11c, CD44, CD56, and CD62L compared to CD56+lo NK-cells, supporting a particular ability of these cells to migrate from blood to tissues and/or a potential advantage to form conjugates with target cells. Interestingly, CD56+lo and CD56+hi NK-cells showed a different pattern of expression of killer receptors that might determine different activation requirements for each of these NK-cell subsets. For instance, absence or low levels of CD16 expression might explain the lower antibody-dependent cytotoxicity activity of CD56+hi NK-cells. On the other hand, the virtual absence of expression of the CD158a and NKB1 immunoglobulin-like and the greater reactivity for the CD94 lectin-like killer receptors on CD56+hi in comparison to CD56+lo NK-cells might determine different MHC-class I specificities for both NK-cell subsets, a possibility that deserves further studies to be confirmed.
Lima
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M
Service of Clinical Hematology, Unit of Cytometry, Hospital Geral de Santo António, Porto, Portugal. mmc.lima@clix.pt
Teixeira
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MA
Queirós
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ML
Leite
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M
Santos
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AH
Justiça
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Orfão
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D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D000943:Antigens, Differentiation / Q000032:analysis*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D019002:CD56 Antigen / Q000032:analysis*; D015815:Cell Adhesion Molecules / Q000032:analysis; D002454:Cell Differentiation; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D007694:Killer Cells, Natural / Q000737:chemistry / Q000145:classification* / Q000276:immunology; D017493:Leukocyte Common Antigens / Q000032:analysis; D008213:Lymphocyte Activation; D008297:Male; D011971:Receptors, Immunologic / Q000032:analysis; D054340:Receptors, KIR; D054342:Receptors, KIR2DL1; D054341:Receptors, KIR3DL1; D016201:Receptors, Lymphocyte Homing / Q000032:analysis
D015703:Antigens, CD; D000943:Antigens, Differentiation; D000945:Antigens, Differentiation, T-Lymphocyte; D019002:CD56 Antigen; D015815:Cell Adhesion Molecules; D011971:Receptors, Immunologic; D054340:Receptors, KIR; D054342:Receptors, KIR2DL1; D054341:Receptors, KIR3DL1; D016201:Receptors, Lymphocyte Homing; D017493:Leukocyte Common Antigens