The Immune System Flashcards
Foreign substance that induces an immune response by the host resulting in antibody production
Immunogen/antigen
Antigen that belongs to the host
Autoantigen
Antigen from the same species as host (but not host)
Alloantigen
Antigen size has what effect on immunogenicity
Bigger antigen = better immune response
What chemical composition makes up the better antigen?
Proteins and polysaccharides
Why are carbohydrates less immunogenic than proteins and polysaccharides?
Smaller
Antigenic determinant site
Epitope
Key portion of an antigen that is involved in immune response
Epitope
Small molecule that when combined with larger carrier protein can be antigenic
Hapten
Function of immune system
Recognize self from non-self
Defend body against non-self
2 lines of immune defense
Natural/innate
Specific/adaptive
Which immune response presents first?
Natural
First line of defense against foreign antigen
External natural defense
Does natural/innate immunity require prior exposure?
No
Does natural immunity have memory?
No
Does natural immunity recognize foreign antigenic structure
No
What is the second line of defense in immunity?
Internal natural defense
Which type of defense consists of cellular, humoral, and inflammatory elements?
Internal natural defense
When is internal natural defense triggered?
When foreign agent penetrates external barriers and enters the body
Most important function of internal natural defense
Phagocytosis
Cellular component of internal natural defense
White blood cells
First cells to respond in innate immunity
Neutrophils
Humoral component of innate immunity
Complement activation and other soluble molecules
Chemical messengers that cause phagocytes cells to move outside of blood stream, into tissues, and to the site of invasion
Chemotaxins/chemokines
Serum proteins (C3b, CRP, antibodies) that attach to foreign particle making it more susceptible to ingestion by phagocytic cells
Opsonins
Molecule secreted by phagocytic cells that activates adhesion molecules on endothelial cells allowing for accumulation of more neutrophils to the site
Cytokines
Function of interferon type 1
Activate natural killer cells
Function of interleukin-1 and interleukin-6
Pro-inflammatory mediators that initiate inflammation; link between innate and adaptive responses
What happens when alternate pathway of complement cascade is activated?
Complement adheres to foreign cells, causing cell lysis
C3a and C5a trigger degranulation of basophils and mast cells, releasing histamines which activates inflammatory response
Major function of inflammation
Heal and generate homeostasis
Mediators involved in inflammatory response within 72 hours after infection
Neutrophils Macrophages Complement Fibrinogen C-reactive protein
Physiologic effects of inflammatory response
Dilation of blood vessels
Increased vascular permeability and diapedesis of WBCs
Increased in CRP
Complement activation
Action of ___ produces main clinical symptoms of inflammation
Cytokines
What causes fever in inflammation
Increase in TNF
Components of specific immunity
Lymphoid tissue and organs
Lymphocytes
Antibodies
Memory
Immune response triggered by primary or secondary exposure
Specific/acquired/adaptive
Primary lymphoid organs
Bone marrow
Thymus
Main source of hematopoietic cells
Bone marrow
Site of B lymphocyte differentiation
Bone marrow
Organ filled with epithelial cells that help in differentiation and maturation process of T lymphocytes
thymus
Secondary lymphoid organs
Spleen
Lymph nodes
Tonsils, appendix, Peyer’s patches, MALT, GALT
Major function of spleen
Filter out old and damaged cells and foreign antigens carried by peripheral blood
Function of lymph nodes
Filter fluid from tissues
Lymphatic fluid consists of?
Fluids and low-molecular weight solutes that pass out of the blood vessel walls into the lymphatic vessels
Site where B cells transform into plasma cells and memory cells
Lymph nodes
Cellular components of specific immunity
B and T cells
Naive B cells only express what antibody class on cell surface
IgM
When does a B cell produce antibody?
After being activated by T cells. B cell divides and differentiates into plasma cell that secretes antibodies
Effector cells that serve regulatory role in immune response
T cells