Direct

Indirect

• physical
• fecal contamination
• airborne droplets

• break chain of transmission
• prevent resistance by limiting use of antibiotic

• use antimicrobials
• destroy nonhuman reservoirs / vectors
• block portal exit
• improve immune system

• direct penetration
• sticks to tissue surface
• slime layer (facilitates adherence)
• adhesion molecules

Characteristics of Microbes:

Help microorganism to spread or invade tissues

Characteristics of Microbes:

Prevents opsonization by antibodies

Characteristics of Microbes:

Prevents microoganism from being phagocytized

Characteristics of Microbes:

What is virulence?

• ability to cause a disease
• microorganism consistently causes disease in all infected hosts
• interact between host/pathogen harms host

Characteristics of Microbes:

Microorganism's ability to mutate in response to environmental conditions

• block foreign material entering body
• provide multilayer protection (like an onion)
• dry surface does not promote organism growth
• sloughing of skin/mucousal cells aids in microorganism remova
• skin has higher fat content to inhibit growth of bacteia and fungi
• mucous membrane linings
• chemical barriers

• acidic environment of skin (lower pH), urine, vagina inhibits bacterial growt
• saliva, mucous, tears, sweat contain bacterial-killing enzyme
• sebaceous gland secretions are anti-fungal

Characteristics of Microbes:

Allows microorganism to survive under harsh environmental conditions

• caused by individuals who take only part of prescribed dose of antibiotics
• Caused by over-prescription of antibiotics
• Allows low-dose antibiotic resistance
• Resistant form may be transmitted to other individuals
• Major threat to successful managemetn of bacterial infection

• polypeptides produced and released by organism
• antigenic, toxic, unstable when exposed to heat
• bind to receptors in target organs
• interfere with metabolic process

Endotoxin or Exotoxin

• interfere with metabolic process

Endotoxin or Exotoxin

• bind to receptors in target organs

Endotoxin or Exotoxin

•  antigenic, toxic, unstable when exposed to heat

Endotoxin or Exotoxin

• polypeptides produced and released by organism

Type of toxin?

• gram - bacteria
• immunogenic part of lipopoysacchaide bacterial cell wall that triggers a massive immune response when bacterium lyses
• immune response when bacterium lyses
• immune response leads to cell shock and multiple organ failure

Endotoxin or Exotoxin

Gram - bacteria

Endotoxin or Exotoxin

Immunogenic part of lipopolysaccharide bacterial cell wall that triggers a massive immune response when bacterium lyses

Endotoxin or Exotoxin

Immune response leads to cell shock and multiple organ failure

• Sexual via semen or vaginal/cervical secretions
• parenteral via blood, blood products, or blood-contaminated needles/syringes
• perinatal in utero, during delivery or in breast milk

1. needle/syringe sharing
2. unprotected sex with infected partner
3. receipt of HIV infected blood or blood products
4. receipt of infected semen
5. uninticipated scalpel or needle injury during care or surgical treatment of infected patients
6. neonatal transmission from an infected mother to her infant

1. Urine, saliva, tears, cerebrospinal fluid, and feces
2. Saliva particulates or aerosol routes
3. dried blood (virus can't live outside the body)

• single-celled organisms
• no internal organelles
• prokaryotes
• DNA in one circular chromosome in nucleod center
• rigid peptidoglycan cell wall prevents osmotic lysis
• contain flagellum, pili, capsule, cell wall, plasma membrane, cytoplasm, ribosomes, plasmid, and nucleoid

• gliding
• spirochetes
• mycoplasmas
• rigid

• actinomycetes
• unicellular forms (both free-living and intracellular obligate parasites)

• reverse transcriptase enzyme
• mRNA
• DNA

• NK
• neutrophils
• basophils
• eosonophils
• monocytes
• macrophages

• B lymphocytes
• T lymphocytes

• eosinophils
• macrophates
• neutrophils
• dendridic cells
• mast cells

• skin/mucous membranes
• lymphoid system
• bone marrow
• leukocytes

• positively
• negatively

• spleen
• thymus gland
• lymph nodes

• B Cells
• T Cells
• Macrophages

• pelvis
• sternum
• ribs
• cranium
• ends of long bones
• vertebral spine

• neutrophils
• basophils
• eosinophils

• Lymphocytes (B, T, NK)
• Monocytes
• Dendritic Cells

• eosinophils
• basophils

Where to B Cells mature?

• B cell
• T cell

bone marrow

thymus gland

• lymph nodes
• spleen
• tonsils
• peyer patches

• granulocytes
• agranulocytes

• neutrophils (macrophage)
• eosinophils (macrophage)
• basophils (mast cells)

• lymphocytes (B, T & NK)
• Monocytes
• Dendritic Cells

• B cells
• T cells
• NK cells

• reservoir
• portal of exit
• mode of transmission
• portal of entry
• susceptible victim

• degranulation
• basophils

• stimulate B cells tomake antibodies and CD8+ cells to seek and destroy
• recognize antigens in association with MHC II molecules
• Protein is necessary to enable TH cells to bind to MHC II protein
• Bind to corresponding antigen and generate signaling cascade in TH cell cytoplasm

• administer a lethal hit to offenders by activating rapid DNA defragmentation and nuclear collapse
• recognize antigen displayed in association with MHC I
• CD8+ protein needed for MHC I biding
• Binding triggers response in cytotoxic T cells similar to that of TH cells (not enough to activate them)
• costimulaators usually present on surface of presenting and responding cells
• activated cytotoxic T cells proliferate into memory and effector cells

• proteins manufactured in cytotoxic T cell
• store in cytoplasm granules
• assemble into pores
• allow into target cell
• degrade DNA
• trigger apoptosis

• classical pathway
• alternative pathway

Complement Cascade

Classical pathway is initiated by _____________

Complement Cascade

Alternative pathway is initiated by_________

Complement Cascade

The altrnative pathway is initiated at _____

Membrane Attack Complex

(MAC)

• neutralize and destroyinvading and harmful agents
• limit spread of harmful agents to other tissues
• prepare damaged tissue for repair

• acute
• chronic

• redness
• swelling
• heat
• pain
• loss of function

• fibroblasts
• endothelial cells
• myofibroblasts

Type of cell

Expansion of new capillaries to mobilize influx of nutrients for tissue repair, wound healing, etc...

• serous
• fibrinous
• purulent
• hemorrhagic

Exudate of RBCs mixed with serous fluid - can be a sign of severe inflammation

T cells recognize and respond to a ____ __________ ______

Variable region: makes up antigen-binding site

constant region - essentially the same for all antibodies of a given class

1. cell to cell binding stimulates intracellular signaling pathways in B and T helper cells
2. promotes clonal expansion and differentiantion
3. B cells need specific cytokines to proliferate and begin antibody synthesis

• precipitation
• agglutination (clotting)
• neutralization
• opsonization
• complement activation (at C1)

Where do antibodies bind to foreign antigens?

Can antibodies activate complement cascade?

If so, where is the cascade?

• IgG
• IgM
• IgA
• IgD
• IgE

• Active
• Passive

• Myasthenia gravis
• Graves disease
• Lymphocytic thyroiditis
• Hyperacute graph rejection

• Deposit of antigen-antibody complexes in tissues results in:
• Activation of complement C3a and C5a, histamine from mast cells
• Subsequent tissue inflammation, chemotaxis from neutrophils relase enzymes and free radicals
• Destruction by phagoyctic cells that are attracted to tissue

• Immune Complex Glomerulonephritis
• Systemic Lupus Erythematosus

• Hapten binds with another "carrier" protein, creating a complete antigen
• Antigen taken up by antigen-presenting cell
• Taken to lymph nodes
• Presented to T helper cells
• Lymphokines released
• Inflammation leads to destruction

• It's a granulomatous HS, which is a chronic type of type IV
• Ag engulfed by macrophages
• Do not kill Ag
• Core of inflammatory cells produced (eosinophils, macrophages, etc.)
• Forms a ball/mass granuloma
• Epithelioid cells fuse into giant, multi-nucleated cells
• Core surrounded by lymphocytes
• Granuloma becomes fibrotic
• Central necrosis (caseous)

• Congenital
• Genetic
• Acquired

• Poor diet
• Stress
• Drugs

• Autoimmunity
• Hypersensitivity
• Immunodeficiency Primary/Secondary Disorders

• Antigenic Mimicry
• Release of Sequestered Antigens
• T-cell Theories
• B-cell Theories

Histamine

• Throat Constriction
• Wheezing
• Tachycardia
• Localized Edema

• Ag exposed to B cells
• B cells crank out IgE
• IgE binds to mast cells (covered with IgE receptors filled with vasoactive substances)
• Exposure of mast cells to Ag---->IgE and Ag's crosslink
• Increases intracellular Ca+2
• Degranulation
• Inflammation

• Hives
• Seasonal Allergic Rhinitis
• Eczema

• IgG
• IgM

• Activated complement fragments (MAC)
• Phagocytic cells that are attacted to target cells by attached ABs

• Administration of 2 reverse transcriptase inhibitors, and as needed for 4 weeks after exposure
• If advanced disease, also take protease inhibitor

• Reverse Transcriptase
• Integrase
• Protease

• Virus enters body and adheres to lectin on DC (uses DC to get into lymph node)
• Binds gp120 envelope to the CD4 molecule on Th cell
• Binding to the Th cell via gp120 allows binding to coreceptors CCR5 and CXCR4 (causes Th cell membrane to melt away and HIV and cell fuse)
• Virus injects core into cell, activates reverse transcriptase, and copying begins
• Virus buds from infected cell, tearing holes in membranes
• As new coies are made, gp120 protein is replicated and allows for fusion to more Th cells
• When Th cells fuse, a huge syncytium forms
• Syncytium prevents receptor availability fro Ab binding (antibodies are now useless)
• At first, CD4 cells are replenished as virus is cleared, but over time, CD4 cells are lost (can't keep up with the virus)

• Decrease in CD4 Th/inducer lymphocytes
• Macrophages become more functionally impaired as infection progresses and also contribue to T-cell decline by increasing CD4 cell death
• B cell responsiveness decreases because of dependence on T-cell helper cytokines

• CD4 count decreases
• CD8 count increases

• Maintained/stabilized
• Set

• ELISA
• OraQuick Rapid HIV-1

• HIV-1
• HIV-2

• Must be confirmed with the Western Blot
• False-negative results can occur

• Depression
• Numbness/tingling/etc. in feet/hands/face
• Confusion/weakness
• Swollen lymph nodes
• Fever/night sweats
• Rapid weight loss
• Diarrhea
• Poor appetite
• Profound fatigue
• Shortness of breath
• Dry/productive cough
• Rash
• Lesions
• Canker sores
• White oral patches (such as thrush)

• Window period/acute infection
• Asymptomatic/subclinical pahse
• HIV-related disease
• AIDS