Immunology Flashcards
What is the goal of the host when it encounters a pathogen
To establish an effective immune response so that the host can survive
Where are the cells of the immune system creates?
Hematopoietic cells in the bone marrow and fetal liver
Lymphoid progenitors become
B and T cells
Myeloid progenitors become
Neutrophils, monocytes, immature dendritic cells
Leukocytes
WBCs, all cells of the immune system or leukocytes
Where do immune responses take place?
In the lymph nodes, spleen, peyer’s patch (intestine) and tonsils
What do the peripheral lymphoid organs do?
Filter blood, lymph, and intestine
Innate immunity
quick response that is not very specific
Adaptive immunity
activation of B and T lymphocytes
Extracellular pathogens
Pathogens that are eliminated by antibody and phagocytosis
Intracellular pathogens
Pathogens eliminated by immune-mediated killing of infected cells
Physical barriers to pathogens
Skin
Mechanical barriers to pathogens
breathing, flushing of urinary tract
Chemical barriers to pathogens
Acids, lysozyme, saliva
Pattern recognition receptors (PRRs)
Bind microbial products on bacteria either intracellularly or extracellularly
PAMPs
sequence on bacteria that bind to PRRs
Inflammation is a change in host to an antigen that allows serum proteins and leukocytes to move from the blood to tissue.
no response
What are some of the early mediators of inflammation released from local cells?
Histamine, serotonin, platelet activating factor, and lysosomal enzymes
Defensins
antimicrobial peptides–T cell chemoattractant
Complement
system of plasma proteins that marks pathogens for destruction
What is C3 cleaved to during complement activation and what do these products do?
C3a–chemoattractant to recruit effector cells, vasodilation and vascular permeability
C3b–attaches to pathogen to mark for phagocytosis
C5a–chemoattractant to recruit effector cells, vasodilation and vascular permeability
Membrane attack complex (MAC)–punches holes in bacterial membrane
Classical pathway of complement activation
C reactive protein binds to specific antigen on pathogen surface
Steps of inflammatory response
- recruitment of cells
- Recognition of pathogen
- Phagocytosis and killing pathogen
Immature dendritic cells’ role in immunity
take up antigen and move from site of injury through lymphatic vessel to lymph nodes-matures and presents antigen to T cell
