Immunology Exam 1 (Intro to innate/adaptive) Flashcards
Foreign substances that induce a host response
Antigens
Attenuation
Making a pathogen less virulent (through heat, aging, or chemical means)
Condition of being resistant to infection
Immunity
Innate immunity
Nonspecific - responses all the same
Prior exposure not required
Immediate effect
No memory generated
AKA natural immunity
Adaptive immunity
Specific for each individual pathogen
Memory is generated and increased response upon repeated exposure
True or False: WBCs play a role in both adaptive and innate immunity
TRUE
Primary function of neutrophils
Phagocytosis and destruction of foreign particles
Functions of eosinophils
Phagocytosis
Neutralization during allergic reactions
Kills parasites
Releases cytokines
Functions of basophils
Releases histamine that induce and maintain allergic reactions
Monocytes vs macrophage
Monocytes in peripheral blood
Macrophages originate from monocytes but found in tissues
How do macrophages function in both innate and adaptive immunity?
Innate - phagocytosis, anti-tumor cell activity, secretion of cell mediators
Adaptive - present antigens to T cells and produce cytokines that regulate immune responses
Mast Cells
Resemble basophils but are found in tissues; induce and maintain allergic reactions, are APCs
Major type of innate lymphoid cell
NK cells
What CD markers do NK cells have?
CD16 and CD56
What do NK cells do?
Kill tumor cells and virus-infected cells
What MHC class do NK cells recognize?
MHC class I
What is the most effective antigen-presenting cell?
Dendritic cells
What is a dendritic cell?
Type of macrophage; APC
Roles in both innate and adaptive immunity
Most potent phagocytic cell
B cell surface markers
Surface Ig, CD19, CD20, CD21, MHC Class II
Where do B cells mature?
Bone marrow
What do B cells differentiate into after contacting an antigen?
Plasma cells
What is the major role of B cells?
Antibody production
Plasma cells
Secrete antibodies (used to be B cells)
Where do T cells mature?
Thymus
What CD marker do ALL T cells have?
CD3+
What CD markers are found on helper T cells, regulatory T cells, and Cytotoxic T cells?
Helper T: CD4+, CD3+
Regulatory T: CD4+, CD3+
Cytotoxic T: CD8+, CD3+
What do regulatory T cells do?
Inhibit immune responses
What do cytotoxic T cells do?
Destroy tumor cells and virus-infected cells (Part of adaptive immunity)
What do helper T cells do?
Produce cytokines that stimulate B cells in antibody production; assist other T cells in cell-mediated immunity
Primary lymphoid organs
Bone marrow and Thymus
Secondary lymphoid organs
Spleen
Lymph nodes
MALT
CALT
T/F: secondary lymphoid organs increase the probability of an immune response
True
Red pulp vs white pulp in the spleen
Red pulp: rich in macrophage, destroys old RBCs
White pulp: contains T cells and B cells
Where are B cells and T cells found in the lymph nodes?
B cells: follicles within the cortex
T cells: paracortex
What occurs in the secondary follicles of the lymph nodes?
B cell transformation; forms plasma cells and memory cells
MALT
found on mucosal surfaces of GI, respiratory, and urogenital tract which is the main port of entry for antigens.
Numerous macrophage and lymphs present
EX: Peyer’s patches, appendix, tonsils
CALT
T cells, monocytes, macrophages, and dendritic cells found on skin
Defenses against infection that immediately act when a host is attacked by a pathogen
Innate immune system
What two systems work to promote phagocytosis in the innate immune system?
Internal and external defense systems
Composed of physical, chemical, and biological barriers that work together to prevent infection from entering the body
External defense system of the innate immune system
How does the skin contribute to the innate immune system?
Part of the external defense system; contains psoriasin (antibacterial), skin pH of 5.6 due to lactic acid and fatty acids, dermis and epidermis contain various cells and glands that contribute as well
How does the respiratory tract contribute to the innate immune system?
Part of the external defense system; cilliated epithelial cells help to trap bacteria and cough/sneeze them out, mucous secretions contain surfactants that block bacteria
How does the urinary and digestive tract contribute to the innate immune system?
Part of the external defense system; urine flushes bacteria out of the tract and vagina has low pH due to lactic acid; and stomach acid at a ph of 1 and normal flora in gut prevent bacterial growth
How do tears and saliva contribute to the innate immune system?
Contain lysozyme which attacks cell wall of gram positive bacteria
What 5 things are part of the internal defense system of the innate immune system?
- PRRs (pathogen-recognition receptors)
- APRs (acute phase reactants)
- NK cells
- Inflammation
- Phagocytosis
What cells are PRRs found on and what is the importance of them?
Macrophage, dendritic cells, neutrophils, eosinophils, monocytes, T cells, mast cells, epithelial cells
When bound to a pathogen they activate phagocytic cells
What do PRRs recognize?
PAMPS
What are types of PRRs?
TLRs, CLRs, RLRs, and NLRs
What are acute phase reactants?
Soluble factors found in serum that increase rapidly in response to infection/inflammation to increase contact between microbes and phagocytic cells, recycle important proteins and minerals during inflammation - part of innate internal defense system
What are types of acute phase reactants? What are their functions/roles?
C-reactive protein - opsonization, complement activation
Serum amyloid A - activates monocytes and macrophages
Alpha1-antitrypsin - protease inhibitor
Fibrinogen - clot formation
Haptoglobin - binds hemoglobin
Ceruloplasmin - binds copper and oxidizes iron
Complement C3 - opsonization, lysis
What two acute phase reactants increase the most during inflammation?
CRP and Serum amyloid A
Cardinal signs and symptoms of inflammation
Swelling (edema)
Redness (erythema)
Heat
Pain
What cells are most involved in phagocytosis?
Neutrophils, macrophage, monocytes, dendritic cells
where are PAMPS found? Where are PRRs found?
PAMPS - found on bacteria
PRRs - found on human host cells
What is the mechanism of NK cells when it comes to killing cells?
If MHC Class I is present on the cell, NK cells will not kill the cell.
If MHC Class I is NOT present on the cell, NK cells will kill the cell
Cell mediated immunity vs humoral immunity
Cell mediated - T cells are key component
Humoral immunity - B cells and antibodies are key component
Double negative stage of T cell differentiation
CD8 and CD4 negative; occurs in the outer cortex of the thymus
Double positive stage of T cell differentiation
Express both CD4 and CD8; positive and negative selection occurs
What is positive and negative selection?
Thymocytes that recognize MHC antigens will survive (positive selection)
Thymocytes that fail to bind to MHC antigens or react too strongly will be destroyed (negative selection)
Th1 cells vs Th2 cells
Th1: activate cytotoxic lymphocytes and macrophages
Th2: regulate B cell activity
What do T reg cells express?
CD4 and CD25
What do T reg cells do?
Secrete inhibitory cytokines to inhibit proliferation of other T cell populations
Pro B cells
Has no BCR or heavy/light chains; the stage directly after a stem cell
Pre B cells
Contain heavy u chains of IgM class and a pre-BCR with short alpha and beta chains
Immature B cells
Has a functional BCR with two light and heavy chains; can become mature if it recognizes self vs non self
Contains: Class II MHC, CD40, CD21
Mature B cells
Develop in the spleen
Exhibit IgM and IgD
Can become plasma cells or memory cells
Marginal B cells
Remain in the spleen; respond quickly to bloodborne pathogens
Follicular B cells
Migrate to lymph nodes and other secondary organs and recirculate
What do plasma cells have on their surface?
CD138 and CD38
Where are plasma cells found and what do they do?
Bone marrow and peripheral lymphoid organs; produce antibodies and contain cytoplasmic Ig but no surface Ig
