Innate Immunity Flashcards
3 groups of lymphoid organs
Sources of lymphocytes
Sites of lymphocyte development
Sites where lymphocytes respond to antigens
Sources of lymphocytes
Yolk sac
Fetal liver
Bone marrow
Primary Lymphoid Organs (sites of lymphocyte development)
Thymus
Bursa
Peyer’s patches
Bone marrow
*No recognition of antigens
Secondary Lymphoid Organs (sites where lymphocytes respond to antigens)
Tonsils Spleen Lymph Nodes Peyer's patches Bone marrow
*Recognition of antigens
Major Lymphoid Tissues
Bone marrow Spleen Lymph Nodes Urogenital System Intestine Mammary Glands Respiratory Tract Salivary Glands Thymus
Time of development Primary vs Secondary lymphoid organs
Primary: early embryonic life
Secondary: Late fetal life
Persistence of primary vs secondary lymphoid organs
Primary: involutes after puberty
Secondary: Persists in adults
Effect of removal of primary vs secondary lymphoid organs
Primary: Loss of lymphocytes
Secondary: No/minor effects
Congenital athymic animals
Have no thymus - hairless mouse and dog.
Skin grafts on mice were all successful due to no immune response to reject foreign material.
System of open ended vessels that return extravascular fluid from the periphery to the blood.
Lymphatics
Lymph nodes are filtering stations
Lymphocyte recirculation
Immune surveillance - waiting for pathogens to arrive so immune response can be initiated
What is the first line of immune response (non-specific)?
Innate immunity (cellular and humoral)
What is the second line of immune response (specific)?
Adaptive immunity (cellular and humoral)
Physical barriers are part of what type of immunity?
Innate (non specific)
Systems with physical barriers
Repro: low pH
Intestinal: pH, mucus, lysozyme, defensins, bile acids
Skin: keratinized, fatty acids, dessication
Urinary: unidirectional flushing
Mammary: Flushing, lysozyme, complement, lactoferrin
Eye: physical flushing, lysozyme
Trachea: mucus, cilia, cough
URT: trap/remove particles in mucus
What is the Complement System?
Collection of 30 different plasma proteins that are individually inert, but interact to create powerful immune response.
Heat-labile serum factor
10% of total serum proteins
What activates the complement system?
Pathogen Associated Molecular Patterns (PAMPs)
or
Ag-Ab complex.
What are the 3 pathways of complement activation?
Classical (antibody dependent) (Ag-Ab)
Alternative
Lectin
All 3 pathways of complement activation lead to what?
Activation of C3 and generation of C5 convertase
Activation of C5
Membrane Attack Complex (MAC)
How does innate immune system recognize microorganisms?
Characteristic structures not present on mammalian cells
Microbial products essential for survival of microbes
What are PAMPs and MAMPs?
Pathogen Associated Molecular Patterns
Microbe Associated Molecular Patterns
Allow innate immune cells to recognize pathogens in the system
Examples of PAMPs
Peptidoglycan in bacterial cell wall Pilin protein Unmethylated DNA Lipotechoic acids and lipoproteins Capsule polysaccharides Flagellin protein
Examples of Pattern Recognition receptors
Neutrophils
Macrophages
Dendritic cells
*Phagocytosis or Endocytosis of microbes
What are DAMPs?
Damage Associated Molecular Patterns
*Macrophage can recognize cytoplasmic release from cell and know it is infected
What activates macrophages?
DAMPs and PAMPs
