Exam 2 - Immunity Flashcards
Th1
INF-gamma, IL-2
Chemotactic for macrophages
M1 activation
CD4
Th17
IL-17
Chemotactic for macrophages
More inflammatory response (good for tough antigens)
CD4
Th2
IL-4
Chemotactic for macrophages and eosinophils
M2 activation
CD4
Tfh
IL-10, TGF-ß
Regulatory T-cell
Decreases T-cell activation, self-recognition
CD4
CTL
CD8 (and CD3) Antigen specific (fruit) MHC specific (bowl)
T-cell epitopes
Continuous, AA chain
Extrinsic APC pathway
Antigen binds surface
Endocytosis and lysosomal degradation
Class II MHC vesicles fuse and bind
Exocytosis and presentation
Intrinsic APC pathway
During extrinsic pathway, some antigen leaks out
Will be loaded onto Class I MHC
Presented as if own protein
(Cross presentation - DC ONLY)
Immune Surveillance
All protein made by cell is expressed on Class I MHC
CTL monitor Class I MHC and activate when needed
Carbohydrate epitopes (T-independent)
Bind B cell with repeating epitope and backbone
B cell activation but no switching
IgM response
Lectins and Mitogens
Lectins: Proteins that recognize sugar
Mitogens: subclass
Can bind and activate sugar on T-cells
Cytokine storm - SIRS - shock
T-Cell Development
Starts at periphery of thymus Pre-T have both CD8 and CD4 Thymus cells have both MHC I and II Selection/specificity or degradation (Positive=normal, negative=Treg, non=degradation)
HLA Gene
Codes for MHC II and I on chr 6
DR = II
B and A = I
Mixed Leukocyte Reaction
Mix donor and host tissue
Small radiation knocks out donor lymphocytes
Measure proliferation of host lymphocytes
MHC Class I
Bowl is one chain
On all cells in body
Activates CTL
HLA B, C, A
MHC Class II
Bowl is half and half on chains
Used on all APC: Macro, DC, B cells
HLA D group (DP, DQ, DR)
Allograft vs. autograft
Allo: Non-identical members of the same species
Auto: self
Allorecognition
T cells can recognize self + antigen lymphocyte
T cells can recognize foreign lymphocyte
Regions of LN
Capsule Subcapsular space Cortex (follicles and germinal centers) - B cells Paracortex - T cells Medulla
High endothelial venule
In lymph nodes
Signal recognition and diapedesis of lymphocytes form blood into lymph
Thymus Structure
Trabeculae divide into pseudolobules
Cortex: densely packed thymocytes with dark nuc.
Medulla: less densely packed
Stromal cells (DC, mac) - provide matrix/support
Hassal’s corpuscles
Hassal’s corpuscles
concentric layers of reticular cells
prduce thymic stromal lymphoprotein
Thymus blood flow
Small arteries enter the capsule and bifucate within the CT septa
Tight junctions by stromal cells create blood-thymus barrier
Spleen bood flow
Splenic artery and vein
Central arterioles that run deep and become discontinuous
Periarteriolar lymphoid sheath surrounds arterioles
Macrophages hang on reticular fibers
White pulp
Periarteriolar lymphoid sheath
Contains germinal centers
primarily T cells
Red pulp
Not white pulp
Contain most macrophages
Blood flows throughout
Mucosal-Associated Lymphoid Tissue
Unencapsulated lymphoid cells
Tonsils, nodules, appendix, aggregations in intestine
Peyer’s patches
M Cells
Deliver antigen to underlying tissues
Natural immunity
Active: Exposure to pathogen
Passive: IgG/IgA passing
Artificial immunity
Active: Immunization with vaccine, toxoid, etc
Passive: Serum with antibodies (serum sickness, type 3)
Example of cross reaction vaccine
Tetanus - one toxin with one toxic part
Remove toxic region = toxoid
Use in immunization
Antibody only partially effective, antitoxin $$$
Conjugate Vaccines
Carb epitope T-independent response
Conjugate carb with toxin
B cell binds, ingests, and displays toxin
Tfh responds to toxin, stimulates B response to carb
Vaccine Adjuvants
Added to vaccines, innate immune response
Increased local cytokines/chemokines (aka innate) result in better environment for presenting APC
Can increase potency of vaccine
Ex. Alum (mimcs PAMP), Lipid A (HPV)
Herd Immunity
Proportion of op that has immunity against (%)
Two outcomes:
1. Non-immune interacts with immune, infections member
2. Chance of transmission based on infectivity
Herd Effect
decrease in infection rate in non-immune part of herd
_____ infectivity requires _____ herd immunity
Higher, higher
>95% in measles (high infectivity)
Viral Immunity
- Mucous membranes and IgA
- Plasma immunity and IgG
- Once in cells, need T cells: Class II (Th) and Class I (CTL) MHC
Antibody titers
Indicate immune defense against disease
reciprocal of maximal dilution of serum that is still positive
If IgM also present or trends up = currently infected
If stable = has disease/vaccine
DNA Vaccines
Inserting antigen coding DNA
Faster creation in event of outbreak
More stable for transport
