Innate Defenses
- require no previous exposure to effectively respond to the antigen
- Includes NK cells, and Phagocytic cells such as Neutrophils and Macrophages
Specific/Adaptive Immunity
- recognizes foreign invaders
- destroys foreign invaders
- retain memory of the encounter
- Includes B cells (humoral immunity) and T cells (cell-mediated immunity)
- B and T cells must be able to differentiate self/nonself
Functions of Helper T Cells
- activate other T cells & Macrophages
- Stimulate B cell proliferation and antibody production
- Secrete pro-inflammatory cytokines
Functions of Cytotoxic T cells
- can kill certain antigens
- can contain cd8
Functions of B Lymphocytes
- produce antibodies
- carry many copies of identical B-cell receptors
- respond to only one antigen epitope
- produce memory cells
Types of Leukocytes (WBCs)
- Granulocytes (neutrophils, eosinophils, basophils)
- Monocytes & macrophage
- Dendritic Cells
- Lymphocytes (NK cells, T & B Lymphocytes)
Leukocytes by numbers
Neutrophils - 60-80% Lymphocytes - 20-30% Monocytes - 3-8% Eosinophils - 1-6% Basophils - 0-2%
Neutrophils
- also known as plymorphonuclear leukocytes (PMNS)
- important in acute bacterial infections
- 5 stages, but only need to know about band cells
- attrcted to areas of inflammation and bacterial products by chemotactic factors
- release toxins (free radicals, defensins, proteolytic enzymes like elastase)
Neutrophilia
increase in circulating neutrophils
Shift to the left
Immature bands are increased during infection
Eosinophils
- circulating granulocytes
- increase in number during allergic reactions and intestinal parasite infections
- major function is to kill intestinal worms
Basophils
- appear during allergic reactions
- granulocytes characerized by granules that stain blue with basophilic dyes
- structurally similar to mast cells
- Mature basophils circulate in the vascular system
Mast cells
- basophils that are found in connective tissue
- live for weeks to months
Basophils AND Mast Cells
- contain histamine
- degranulation of either begins the inflammatory response associated with allergic reactions
- Involved with wound healing and chronic inflammatory conditions
Monocytes AND Macrophages
originate from bone marrow stem cells of the myeloid lineage
Monocytes
- immature macrophages that circulate in bloodstream
- become macrophages when entering the tissue
Macrophages
- can ingest several times as many microorganisms than neutrophils
- Live for months to years
- capable of cell division
- secrete cytokines
- important in wound healing
- important in antigen presentation
Dendritic Cells
- derived in the bone marrow just as monocytes and macrophages
- located throughout the body as part of the mononuclear phaocyte system
- antigen-presenting cell
- produce chemical messangers
Lymphocytes
- small, round cells with large, round nucleus
- sorted by cell differentiating markers
- 3 types (NK Cells, T Cells, B Cells)
NK Cells
- function in innate immunity
- effectively kill tumor and virally infected cells without previous exposure
- not specific for particular antigen
Inflammation Markers
- Acute phase proteins increase
- Erythrocyte sedimentation rate (ESR) increase
C Reactive Protein
an acute phase protein that is released into the blood when there is tissue injury that causes inflammation
Acute Phase Proteins
proteins that are released into the blood when there is a tissue injury
Components of Healing
- FIbroblasts (new connective tissue)
- Endothelial Cells (form new capillaries)
- Myofibroblasts (induce wound contraction)
Absolute Neutrophil Count
- the real number of WBCs that are actually neutrophils
- an absolute neutrophil count less than 500 cells/microliter is considered low
MHC Compatability
- also known as the human leukocyte antigen (HLA)
- Mark body cells as ‘self’
- Polymorphism ; no one has the same MHC genotype unless identical twins
- 3 classes: MHC I, II, III
Different Types of Immunoglobulins
- IgG, IgM, IgA, IgD, IgE
IgG
- most common type and the smallest
- easily escapes bloodstream to enter interstitial fluid
- circulate as single molecules
- can cross the placenta
IgM
- mostly found in intravascular pool; cannot penetrate vascular wall
- First to be produced on exposure to antigens or after immunization
- major antibody found on B cell surfaces
- Works best to activate the complement
IgA
- a dimer
- produced by plasma cells under skin/mucous membranes
- found in saliva, tears, tracheobronchial secretions, colostrum, breast milk, and GI/GU secretions
- responsible for passive immunity
IgD
- found in tiny amounts in serum
- located primarily on B cell membranes
- acts to stimulate b cell to multiply, differentiate, and secrete other specific immunoglobulins
IgE
- helps against parasites
- functions as a signaling molecule
- causes mast cell degranulation when antigen detected at mast cell surface
Mediators of Inflammation
- histamine
- serotonin
- bradykinin
- Complement proteins
- prostaglandins
- Leukotrines
- proteases
- oxygen free radicals
Acute Inflammation
- short in duration, lasting less than 2 weeks
- involves a discrete set of events
Chronic Inflammation
- more diffuse
- extends over longer period
- May result in scar tissue formation or deformity
WBCs involved in inflammations
neutrophils, basophils, eosinophils, mast cells, and phagocytes
Tissue Transplantation
The structure of an individual’s MHC proteins
is assessed to determine the “tissue type” when matching for tissue
transplantation procedures.
Bed Sores (Decubititus)
4 stages
- tissue open
- tissue breakage
- tissue damage, can see bone and caritlidge
- dead tissue eschar
