Innate and Adaptive Immunity Vaccines - Slide Deck

Immuno Exam 1 - Basic Science Core

Innate Immunity

• First line of defense against pathogens

• We are born with innate immunity and it develops based on our genetic make-up

• Rapid response: within minutes of an infection

• Not specific: same molecules/cells respond to a range of pathogens

• Has no memory: same response after repeated exposure

• The mechanisms involved in innate immunity might not be sufficient to overcome and defeat the infection, either in a “timely fashion” or at all

• Is the “Complement system”

Innate Immunity - Physical barriers & chemical defenses

• 1) Skin

• 2) Mucous membranes

• 3) Acid, enzymes, mucus, others

Innate Immunity - Cellular defenses

• 1) WBCs

• 2) Cytokines

Layers of the Skin (3)

• Epidermis (outer layer)

• Dermis (inner layer)

• Hypodermis (Deepest Layer)

Epidermis

• The epidermis contains no blood vessels and is entirely dependent on the underlying dermis for nutrient delivery and waste disposal via diffusion through the dermo-epidermal junction

• The epidermis is a stratified squamous epithelium

• consists primarily of keratinocytes in progressive 5 layers

• Tightly packed together

Mnemonic for the 5 Layers of Epidermis

Come

Lets

Get

Sun

Burnt

5 Layers of Epidermis

• 1) Stratum Corneum

• 2) Stratum Lucidum

• 3) Stratum Granulosum

• 4) Stratum Spinosum

• 5) Stratum Basale

Stratum Basale

Contains the “Stratum germinativum” which:

• a single layer of cells that divides constantly (“stem cells of the skin”) – as new cells form, older ones are pushed toward the skin surface

Stratum Corneum

• the largest and most abundant of the epidermis.

• This layer ranges in thickness from 15-100 or more cells depending on anatomic location and is the primary protective barrier from the external environment.

• Contain “Dead Keratinocytes”

  • Provide elasticity

  • Protect underlying (living) cells from drying out

Desquamation

• Sloughing off of skin cells

• Keratinocytes → keratin (Main cells sloughed of) → Corneocytes (keratin-filled sacs)

Four types of Cells of the Epidermis

1) Keratinocytes

2) Melanocytes

3) Dendritic cells (Langerhans cells)

4) Nerve endings

Keratinocytes (Squamous Cells) /Corneocytes

• Produce keratin (strength, flexibility, waterproof)

Melanocytes

Produce melanin (pigment that absorbs harmful UV radiation from sunlight before it reaches tissues below the skin)

Ratio of melanocytes to keratinocytes

• Exposed to the sun → 1:4

• Not exposed to the sun → 1:30

Dendritic cells (Langerhans cells)

• Identifies bacteria and other invaders and presents them to the immune system for recognition and destruction

• Sensory Cells

Nerve Endings

Allow for sensory perception

Dermis

• Deeper to and thicker than epidermis

• Thickness = 0.3-4.0 mm

• Mainly fibroblasts are scattered rather than packed, plus they are interwoven with fibers

• Some of the fibers are tough & strong (collagen), others are thin and elastic (become wrinkles when degraded)

• Has Dermal papillae

Dermal Papillae

• Found in the dermis

• Upward projections that create the ridges & grooves of the fingerprints

Dermis Components (5)

• 1) Nerve endings

• 2) Hair follicles

• 3) Sweat (eccrine) glands

• 4) Sebaceous glands (pilosebaceous follicles)

• 5) Blood vessels

Sebaceous Glands

• Found over the entire surface of the body except the palms, soles, and dorsum of the feet.

• They are largest and most concentrated in the face and scalp where they are the sites of origin of acne.

• The normal function of sebaceous glands is to produce and secrete sebum, a group of complex oils that include triglycerides and FATTY ACIDS, wax esters, squalene, cholesterol esters, and cholesterol.

Sebum (4 fatty acid)

• Lubricates the skin to protect it against friction and makes the skin more impervious to moisture.

Contains 4 fatty acid types:

1) Sapienic acid

2) Lauric acid

3) Oleic acid

4) Palmitoleic acid

• These Fatty acids can disrupt the structure and

  function of bacterial cell membranes

Palmitoleic acid

• Found in Sebum

• Also effective in blocking the adherence of Candida albicans to the skin

Salivary Glands (3 Types)

• Secretions are important for the hygiene and comfort of the mouth and teeth!

• Three Main Glands are:

  • Parotid

  • Submandibular

  • Sublingual

• The daily secretion of saliva normally ranges between 800-1500 ml.

• Secretions aid in lubrication and digestion of food, and enhance speech, taste, and swallowing.

• It also dissolves and washes out food particles from between the teeth

Anti-Pathogen Components in Saliva (4)

1) Lysozymes

2) Lactoferrin

3) Histatins

4) Immunoglobulin A (IgA)

Lysozymes

• Enzymes that can attack bacterial cell walls

• In Saliva

Lactoferrin

• In Saliva

• Which chelates iron, preventing the multiplication of

  organisms that require it for growth

Histatins

• In Saliva

• Which are a group of proteins that can disrupt bacterial

  & fungal cell membranes

Immunoglobulin A (IgA)

• In Saliva

• Which prevents bacteria from adhering to

  surfaces in the mouth

Lacrimal Glands & Lacrimation → Anti-Pathogen Components of Tears

1) Lysozymes

2) Lactoferrin

3) Lipocalins, which are proteins that also chelates iron

4) Immunoglobulin A (IgA)

Gastric Pits

• Deep channels called gastric pits, which are lined with columns of specialized cells called gastric glands