Inflamasome, Neutrophils, NK cells Macrophage receptors, Opsonization. Flashcards
Direct interaction of macrophage with antigen
PRR and PAMPS
Indirect interaction
-Molecules bind to pathogens, –opsonins interact with cognate receptors on phagocytes
opsonins and their receptors
Fc-gamma, Fc-gamma-R - CR-1, C3b - CRP binding site, CRP
Neutrophils differentiate from
GM progenitors using G-CSF
half life of neutrophils
8 hours
neutrophils enter tissue during
inflammation by CXCL8/IL8(chemokine) or C5a(Chemotactic factor
neutrophils similarities to macrophages
-same direct or indirect recognition -same phagocytosis and armamentarium -affected by IFN-gamma, TNF, IL-4 IL-10 and TGF-beta -PAMP PRR system
neutropihls do not
present antigens for t cells or secrete cytokines.
inflammasome activation leads to
Pro-caspase-1 production which is changed to Caspase 1. Caspase 1 cleaves IL1 and IL18 and then they are secreted
Thp is activated by
dendritic cell to Th0
Th1 is created by
Activation of Thp by dendritic cell, which is changed to Th0 and then to Th1 by cytokines IFN-gamma, IL-2, TNF. Dendritic cells also secrete IL 12 which tells NK cells to secrete IFN- gamma. The IFN gamma, IL-2
indirect is the interaction of
an intermediary protein which has bound to an antigen with a receptor on the phagocyte.
opsonins are generated when
components other than phagocytes are acitvated in response to the pathogen
the sources of the different opsonins
B cells secrete IgG Macrophages secrete IL- 6 which targets hepatocytes and the hepotcytes secrete CRP Complement system releases C3b
macrophages are not as affective as antigen presenting cells as
dendritic cells
Macrophages are more likely to serve as APC in
secondary immune response
secondary immune response usually occurs at
the site of infection
primary immune response usualy occurs at
secondary lymphoid tissue
macrophages also express like dendritic cells
CD4 CCR5, CXCR4 which means they can be infected with HIV
macrophage activation upregulates
Class II MHC and costimulatory molecules.
iNOS activation requires two signals
a priming signal delivered by bacterial products and a second signal delivered by TNF
source and distribution of NK cells
differentaited from lymphoid progenitor in the bone marrow and presents in the blood, spleen and peritoneal exudate.
Roles of NK cells
destroy infected and tumor cells, secrete INF gamma following activation by IL12
NK inhibitory receptors
Class 1 MHC receptors,
binding of NKG2D on target cell can lead to
destruction of that target cell. it is a stres is induced activator
MICA
MHC class 1 chain related gene A, may be upregulated on virally infected cell. THis activates.
MHC class 1 can be upregulated following
exposure to cytokines IFN gammaor IFN Alpha/beta
IFN Alpha is released by
virally infected leukocytes
IFN beta is released by
virally infected fibroblasts
MHC classs 1 can be downregulated by
stress viral infections tumors (which can all lead to upregulation of MICA as well. )
antibody cell mediated cytotoxicity is contingent on
B cell activation and production of IgG antibodies that recognize an antigen on the target cell.
when IgG antibodies bind to target cells
the portion that is available for binding is the Fc gamma region (IgG binds to target cell via FAB region)
NK cells expressing receptor Fcgamma R
bind to the target cell via Fc-Gamma
