Cells and Tissues of the Immune System Flashcards
Immunogen
An antigen that induces an immune response
Antigen
A molecule that binds to (is recognized by) antibody or T cells
Increased Immunogenicity vs Decreased Immunogenicity
- Large vs. Small (MW Intraperitoneal > Intravenous or Intragastric
- Multiple differences vs. Few differences
- Slow release vs. Rapid release
Passive Immunity
Receiving preformed antibody
Rapid protection
Short Duration (T1/2 for about 3 wks)
Active Immunity
Exposure to a foreign antigen
Slow Protection
Long Duration - memory lymphocytes
Innate Receptors
Pattern-Recognition Receptors
- Toll like receptors, Nod-like receptors
- Limited diversity, non clonal expression
Adaptive Receptors
Antigen Receptors
- T-Cell receptor
- B-Cell receptor
- Somatic recombination leads to great diversity
Adaptive Memory
Clones of lymphocytes remain in the body and will recognize and respond to antigen more rapidly than the first, initiating exposure event
Pros and Cons of T-Cell (cellular) response
Pros: Strong, life-long immunity
Cons: May revert to virulent form
Pros and Cons of B-Cell (humoral) response
Pros: Stable and safer than Live (attenuated vaccine)
Cons: Weaker immunity - requires booster vaccine
Live Attenuated Vaccine
Micro-organism is modified to decrease pathogenicity, limited growth after injection
Mainly induces T-Cells
Inactivated Vaccine
Pathogen is inactivated but retains an immunologic epitope on surface
Mainly induces B-Cells
WBC (4.0 - 10.0^3/μL) Differential
Neutrophils: 34-71% Lymph: 19-53% Mono: 5-12% Eos: 0-7% Baso: 0-1%
Cells of the innate immune system
Phagocytes:
- Neutrophils
- Macrophages
Granulocytes:
- Eosinophils
- Basophils
- Mast Cells
Cells Linking the Innate and Adaptive Immune Systems
Dendritic Cells
NK cells
Cells of the adaptive immune system
Lymphocytes
Monocyte/Macrophage
Circulate and enter tissue and differentiate into tissue macrophage, present in all tissues of the body
Neutrophils morphology
Polymorphonuclear cells
Eisonophils
Motile phagocyte important in parasite infection and allergy - granules contain heparin, hydrolytic enzymes
Basophils
Non-phagocytic, circulate in blood - Release pharmacologically active immune mediators
Mast Cells
From bone marrow and emigrate/ differentiate in tissue - Granules contain heparin and histamine
Important in allergic responses
Dendritic Cells
Derived from the same bone marrow progenitor as monocytes and migrate and reside in tissues near site of microbe entry
- Primary function is as an Antigen Presenting Cell
Natural Killer Cells
Large Granular lymphocytes which recognize foreign cells of many different antigenic types
Active without prior exposure to antigen
Active independent of antigen presentation
Specialize in killing of virus-infected cells and tumor cells
Primary (Generative) Lymphoid Tissues
Bone Marrow: hematopoietic progenitors, lymphocyte development
Thymus: Development and maturation of T lymphocytes
Secondary (Peripheral) lymphoid tissues
Lymph nodes
Spleen
Mucosal or Skin-Associated lymphatic tissues (Peyer’s patches)
Process of Antigen/Microbe Exposure
Pathogen gains entry into body through epithelium and then into the Dendritic cells
Dendritic cell changes which allows it to leave periphery of skin and move into a lymph node
Peripheral Immune Tissues (Location of B and T Cells)
T Cell Zone = Periarterioolar lymphoid sheath in Central arteriole
B Cell Zone = Follicles in Marginal zone
Peyer’s Patch
Specialized Collections of lymphatic tissue in the ileum
