RESUMO
As IL-2 and IFN-α modulate NK cell activity it was of interest to investigate the expression of newly defined NK cell receptors and augmented NK cell activity in healthy individuals after cytokine in vitro treatment. Peripheral blood lymphocytes (PBL) obtained from 31 healthy volunteers treated for 18 h with 200 IU/ml IL-2 and 250 IU/ml IFN-α were evaluated for NK cell cytotoxicity. Expression of NKG2D, CD161, CD158a, CD158b receptors was analyzed on CD3â»CD16+ NK cells, cytotoxic CD16(bright) and regulatory CD16(dim) subsets by FACS flow. The found induced significant in vitro enhancement of NK cell activity by both cytokines is supported by specific cytokine induction in PBL of pSTAT1 and pSTAT5, determined by Western blotting, as well as induction of IRF-1 transcription. Both cytokines induce significant up-regulation of NKG2D expression while only IFN-α induced significant up-regulation of CD161, with no alteration in KIR expression by either cytokine on CD3â»CD16+ NK cells. Investigated cytokines did not induce change in NK cell bright and dim subset distribution. Moreover, we find that, not only cytokine receptor induction on the CD3â»CD16+ NK cells, but also simultaneous increase in their percentage and/or density on CD16(bright) and CD16(dim) subsets, represent good indicators of receptor cytokine-susceptibility. As the role of NK cells has been shown in the loss of tolerance, infection and cancer, the data obtained in this study may be of help in NK cell profiling, by giving referent values of cytokine-induced novel NK cell receptor expression either in evaluation of these diseases or in immunomonitoring during cytokine immunotherapy.
Assuntos
Citotoxicidade Imunológica/efeitos dos fármacos , Interferon-alfa/farmacologia , Interleucina-2/farmacologia , Células Matadoras Naturais/efeitos dos fármacos , Subfamília B de Receptores Semelhantes a Lectina de Células NK/biossíntese , Subfamília K de Receptores Semelhantes a Lectina de Células NK/biossíntese , Receptores de Células Matadoras Naturais/biossíntese , Adulto , Linhagem Celular Tumoral , Feminino , Humanos , Células K562 , Células Matadoras Naturais/metabolismo , Linfócitos/efeitos dos fármacos , Linfócitos/metabolismo , Masculino , Pessoa de Meia-Idade , Subfamília B de Receptores Semelhantes a Lectina de Células NK/sangue , Subfamília B de Receptores Semelhantes a Lectina de Células NK/genética , Subfamília K de Receptores Semelhantes a Lectina de Células NK/sangue , Subfamília K de Receptores Semelhantes a Lectina de Células NK/genética , Receptores KIR2DL1/antagonistas & inibidores , Receptores KIR2DL1/genética , Receptores KIR2DL3/antagonistas & inibidores , Receptores KIR2DL3/genética , Receptores de Células Matadoras Naturais/sangue , Receptores de Células Matadoras Naturais/genética , Regulação para Cima/genéticaRESUMO
Inhibition of natural killer (NK) cells is mediated by MHC class I receptors including the killer cell Ig-like receptor (KIR). We demonstrate that HLA-C binding peptides can function as altered peptide ligands for KIR and antagonize the inhibition mediated by KIR2DL2/KIR2DL3. Antagonistic peptides promote clustering of KIR at the interface of effector and target cells, but do not result in inhibition of NK cells. Our data show that, as for T cells, small changes in the peptide content of MHC class I can regulate NK cell activity.