《浙江大学医学免疫学经典课件免疫-白细胞分化抗原》课件.pptVIP

NK cells were defined initially by their ability to lyse certain tumor cell lines and virally infected cells without prior immunization,and so mediate a form of innate (or natural) immunity that is termed “natural killing”. NK cell (p140) Derive from a bone marrow precursor are large granular lymphocytes distribution: peripheral blood ,spleen Surface markers 1. CD56 2. CD16(FcγRⅢ) ADCC 3. FcR NK cells are generally TCR- , mIg-, CD16+, CD56+. The receptors associated with activation or inhibition 1.The receptors recognizing MHCⅠ molecules (1) Killer immunoglobulin-like receptor ,KIR KIR 2DL ITIM inhibitory receptor KIR 2DS binding with DAP-12( ITAM) activated receptor KIR 3DL ITIM inhibitory receptor KIR 3DS binding with DAP-12( ITAM) activated receptor ·Intracellular signalling pathways coordinate inhibitory and activating signals (2) Killer lectin-like receptor,KLR CD94 NKG2A ITIM inhibitory receptor CD94 NKG2C binding with DAP-12( ITAM) activated receptor (3) The significance of KIR and KLR NK cells are prevented from killing host cells because they recognize the host classⅠMHC molecules. Thus, they only attack cells whose classⅠMHC molecules are lost or altered ,as occurs frequently in malignancy or viral infection. 2.The receptors recognizing non-MHCⅠ molecules (1) NKG2D binding with DAP-10 ( ITAM) activated receptor ligand: MⅠC A/B (on some tumor cells) (2) natural cytotoxicity receptor,NCR NKp46,NKp30 binding with CD3(? ? ) NKp44 expressed on activated NK cells binding with DAP-12 ( ITAM) activated receptor The mechanism of cytotoxicity 1. Perforin / granzyme pathway 2. Fas / FasL pathway 3. TNFα / TNFR-1 target cell apoptosis question Master the concept of LD