L30 Immune Histology Flashcards
immune system
groups of cells and their secreted products, tissues, and organs that monitor the body surface and internal fluid spaces to provide defense against pathogens
what are two threats to the immune system
infections (neutralize harmful foreign invaders)
cancer (neutralize harmful foreign invaders)
nonspecific vs specific defenses
skin, mucous membranes, chemicals//phagocytosis, complement, interferon, inflammation, fever
vs
lymphocytes and antibodies
threat detection requires
host cells to distinguish self from nonself or infected self or transformed self
what surface molecules do host defense
PRR
MHC-I
MHC-II
TCCR
CD
PRR
pattern recognition on many host cells to detect antigens (TLRs)
DETECT ANTIGENS
MHC-I
display host-made peptides that can be surveilled by lymphocytes called CD8+ T cells (and NK cells) which
destroy host cells that show signs of being infected by a virus or are undergoing cancerous transformation
altered levels MHC-I = this host cell should die
CD8+ T cells
VIRUS/CANCEROUS TRANSFORMATION
MHC-II
used by antigen-presenting cells (APCs) to display foreign peptides from phagocytized antigens to CD4+
T cells that leads to secretion of antibodies that target the antigen
ANTIGEN PRESENTING CELLS (APCS)
foreign peptides
CD4+ cells
secrete antibodies
plasma cells
antibodies
TCR
T cell receptors on CD4+ and CD8+ T cells that bind to antigens on MHC protein complexes
CD4+ and CD8+ t CELLS
CD
co-receptors for the TCR that facilitates cell-cell communication
antigen=
activate immune response
immune response sequence of events
innate response
Ab-mediated (humoral) adoptive response
cell-mediated adoptive response
innate response
first step
- APCs recognize antigen via PRR
- Granulocytes respond (Neutrophils, eosinophils, monocytes, NK cells )
Ab(antibody)-mediated (humoral) adAptive response
second step
- APCs via MHC-II molecule
- CD4+ T cells (TCR, CD)
- B cells
- Plasma cells: antibodies
Memory: CD4+T CELLS, B cells AKA ADAPTIVE IMMUNITIY
blood used to be called
humoral
Cell-mediated adaptive response
third step
- APCs (via MHC-I)
- CD8+T cells (TCR, CD): cytotoxins
Memory: CD8+ T cells
non specific immunity
specific immunity
dendritic cell types
monocytes/macrophages
Langerhans cells
Basophil
Neutrophil
Eosinophil
review:
monocytes/macrophages
Langerhans cells
Basophil
Neutrophil
Eosinophil
Lymphocyte types
T cells
B cells
Plasma
high number of neutrophils
innate immune response
7
adaptive immune response takes place within ___ tissue within ___ structures
connective
lymphatic nodules (lymphatic follicles)
components of lymphatic nodules
germinal center
mantle
germinal center
site of B cell clonal expansion (proliferation) and differentiation into plasma cells.
in lymphatic nodules
mantle
in lymphatic nodules
surrounding region that contains naïve B and T cells unchallenged by antigens, and memory cells
Numerous lymphatic nodules in a tissue suggests __
an adaptive immune response
steps involved in lymphatic nodule function
- APCs like dendritic cells present antigens to naïve CD4+ T cells (and naïve CD8+ T cells).
- Activated CD4+ T cells induce B cell clonal expansion, forming a germinal center.
- Follicular dendritic cells (FDCs) present antigens to B cells to test reactivity.
- ‘Tingible body macrophages’ phagocytose non-reactive apoptotic B cells.
- Reactive B cells differentiate into plasma cells and memory B cells.
lymphatic organs types
primary and secondary
primary lymphatic organs
sites where B and T cells are formed and gain immunocompetence (also
called central tolerance; i.e., learn to be nonreactive to self-peptides).
- clonal deletion (apoptosis) of dysfunctional lymphocytes
- bone marrow
- thymus
bone marrow
site of T & B cell formation; B cell central tolerance
thymus
site of T cell central tolerance
secondary lymphatic organs
sites where adaptive immune responses occur
- sites where peripheral tolerance further reduces the number of autoreactive cells
through clonal deletion to try to prevent autoimmune disease
- secondary organs have a reticular stroma that facilitates movement of immune cells
- contain numerous secondary lymphatic nodules during infection