Immunology Exam 2

Memory Cells (Plasma Cells do not have these)

• Antigen Independent Differentiation
• Bone Marrow
• Thymus
• Bursa

• Antigen dependent differentiation
• Lymph Nodes
• Spleen
• MALT, SALT, etc.

• Support
• Produce cytokines to advance differentiation

Lymphocytes in the thymus

Process of leaving vascular system and entering thymus

• Epithelial- Self identity is established (positive selection)
• Macrophages- Ensure don't trigger immune response with self (negative selection)

Lymph Nodes

• Cortex - B Cell Region
• Paracortex- T Cell Region (mostly Th)
• Medulla- Plasma Cell Region

• Assemblages of lymphocytes in the cortex of lymph nodes.
• Mostly naive but can interact with antigen here

• Where lymphocytes interact in lymph node. When B cell is activated by Th cell, a follicle will surround the germinal center
• Another site of selection (FDC participates in selection process)

• New name for cell that has gone through the germinal center. Will eventually become a memory cell.
• No germinal center means no memory cells

Majority of spleen is RBCs, but also sheathe of WBC called Pari Arteriolar Lymphoid Sheaths

• Macrophage (APC)
• B Cells
• T Cells
• Blood Vessel

From blood stream (not lymphatic)

• Lines blood vessel
• Tall epithelial layer (HEV) with unique cell surface components where cells can leave vascular system and enter lyphoid tissue

During margination (leukocytes leaving circulation), the organ tells the epithelial cells to express certain receptors to allow specific cells to pass

• Process of squeezing through
• Chemokines regulate receptors

• Mucin-like CAM
• Integrins
• (didn't note other two)

• Occurs when CD11/CD8 integrins are defective
• These two are components of ICAMs
• Leukocytes can,t get out so no inflammation

• Due to breach of non-specific barriers
• Manufacture CAMs and receptors on nearby epithelium
• Occur due to vasoactive factors

Injured tissue: membrane manufactures leukotriene (signal) which stimulates Mast Cells to produce vasoactive factors

Bacterial membranes: Trigger macrophages (also mast cells) to release vasoactive factors

Complement acts as a chemotactic factor, drawing leukocytes up concentration gradient

Toll Like Receptor that binds LPS

Natural Killer Cells

Phagocyte usually has to bind multiple receptors to pathogen. Then engulf it in phagosome

C3b binds to general component of bacteria and is then received by CR1 on phagocyte

• Phagosomal Killing-
• Granuloma Formation

• Protein Kinase C on phagosomic membrane
• NADPH oxidase- toxic chemical (neutrophils make so much that they kill themselves)
• Myeloperoxidase- only found in neutrophils

Immune system surrounds pathogen with phagocytes

• Antibody= heat stable
• Complement= heat labile

• C1 is activated when encounters Ag-Ab complex
• Leads to formation of MAC

• Very fragile pathway
• Involves many steps
• Evolutionarily the oldest pathway
• Leads to C3b without antibody (true innate)

• Manos Binding Lectin (MBL) is soluble and binds to bacteria. Serves as an opsinin.
• Doesn't require antibody (true innate)
• Leads to same pathway as classical, but different starting units

• C5 - C9
• Best used for lysing Gram Negative
• C8 Drill
• C9 Case for drill

Comes in 2 forms. One for classical pathway and one for alternative pathway

• H Factor competes with B factor (inhibitory factor)
• Factor I + Factor H = attachment site for C3b which makes iC3b (innactive)
• CR1 binds Factor 1 which competes for the binding site on C3b

Usually just opsinin. Difficult to get to C5 convertase

• Attach to Fc receptor to clean up Ab-Ag complexes
• Bind receptors on RBC and go to spleen
• Attach to virus attachment sites to prevent access
• *Needed to reach C5

C3a reacts to cause increase in chemotactic and vasoactive factors

• Produced by liver in response to IL-1 and IL-6 from macrophage.
• Serves as an opsinin, but binds C1qrs to activate it

Vasoactive Factors contract smooth muscle to redirect blood flow to area

• Extra blood
• Metabolic activity
• Bacteria have narrow tolerance to heat
• If doesn't work locally, will develop fever

Vasoactive factors cause epithelium to loosen so that liquid plasma can enter

Vasoactive factors, but more importantly kinin cascade

• Antimicrobial peptide
• One of the most ancient immune defenses

• Arose in invertebrates
• Echinoderms

• Wandering phagocytic cells in echinoderms
• Give rise to C3 analogous protein & Factor B analogous protein
• Produce IL1 analog in presence of pathogen (self proliferation)

Macrophages release this to trigger proliferation of T cells

Amoeboid immunocytes

Have MHC like proteins

• Only ones to have true lymphocytes
• Lampreys were first
• Sharks were first to show T and B cell differentiation (first to have thymus and spleen)

Hematopoietic Stem Cells are sensitive to UV, so better to encase in bone

• Lymph Nodes
• MALT, SALT

• 2 Identical Heavy Chains
• 2 Identical Light Chains

• N terminus is on Fab
• C terminus is on Fc

• L chain duplicated twice next to each other
• H chain duplicated four times

• Neutralization of pathogen
• Complement Activation
• Opsinization
• Ab-Dependent Cellular Cytotoxicity (ADCC Reaction)

• 7
• IgM
• igD
• igG (2)
• IgE
• IgA (2)

Glycine and Lysine

Cuts hinge region into 3 sections

Breaks disulfide bonds (4 regions)

Cuts away Fc at disulfide bridge. Retains bivalent structure to bind 2 antigens

• Kappa (dominant form)
• Lambda

• Hypervariable is antigen detecting
• Also complementarity determining region (CDR)

CDR3 is most variable

Affinity- Strength of association between antibody and antigen

Avidity- Attachment to several epitopes of antigen

• Some antigens occur on classes of microorganisms
• An antibody can attack any of these that it recognizes

• Doesn't have signal transduction machinery
• borrow from Iga and IgB

• IgM can have 1 or 5 antibodies
• IgA can have 1, 2, 3, or 4 antibodies (usually 2)

Binds Fc Regions to polymerize antibodies

• Isotype- constant region
• Allotype- constant region
• Idiotype- variable region

• Dimeric IgA binds secretory receptor
• Enclosed in phagosome
• Moves across
• Leaves as Secretory IgA (SIgA)

• Presence of J chain brings them together
• Linkage is broken within phagosome

IgG and IgM

Secreted has hydrophilic end, membrane bound has hydrophobic end that anchors it to membrane

Coelomocyte

DiGeorge Syndrome

White Pulp

CD4+CD8+cell

HEV

Lysozyme

Chronic Granulomatosus Disease

Leukocyte Adhesion Deficiency

Fever

C3 Convertase

Stomach Acid

B cells

MAC

Peyer's Patch

Phagolysosome