Innate immunity exam 3 diversity

Protection against pathogens

• your body needs to be eble to distinguish between self and nonself

• some defenses always in-place (automatic always on)

  • skin-sweat, normal flora

  • Other defenses activated

Three phases of how an immune system operates

recgnition phase

activation phase

effector phase

Recognition phase

• recognizing pathogen

Activation phase

• mobilization of cells/ molecules to help

Effector phase

• Inavder destroyed

Defense MEchanisms

• innate

• adaptive

innate defense mechanism

• genetically programed

• nonspecfic

• first line of defense

• physical barrier, toxic molecules, general phagocytic cells

• relative quick response (min/hours)

Adaptive defense mechanism

• targets specific pathogens

• antibodies made to find specific pathogens

• slow, long-lived

• evolved in vertebrates

all animals have ___ defense

innate

physical / chem barriers

• physical things to stop pathogens from getting in

• hard exoskelton

• egg shell

Phagocytic cells

• the gaurds of defense. they “attack” any invaders if they’ve past the physical boundaries

• large cells they ingest pathogens, by phagocytosis

molecules toxic to invading cells

• peptides that disrupt pathogen cell membrane

TLRs

Toll-Like Receptors

TLRs

• recognition and activation phases developed early in animal evolution

• they participate in innate defense

• vertebrates

  • TLRs bind to conserved structures on microbes

  • pathogen-associated molecular patterns (pamps)

  • PAMPs binding triggers signal transduction pathways

PAMPs

• Pathogen -associated molecular patterns

• PAMP binding triggers signal transduction pathways

  • gene expression of anti-pathogen molecules

• Flagellin, lipopolysaccharides, fungai chitin, neclic acid variant (viruses)

types of cells and their func.

• white blood cells

• phagocytes

• lymphocytes

in 1 mL of human blood there are billion RBCs and _ billion WBCs

• 5

• 7

White blood cells

• also known as leukocytes

• specialized for immune system fuc.

• Second line of defense

• work in both ADAPTIVE & INNATE

• develop from stem cells in bone marrow

Lymphocytes

• ADAPTIVE & INNATE

• include T and B cells

MAMMAL defense - lymphatic system

• components of defense system throughout body

• lymphoid tissue

• blood plasma

• lymph

Lymphoid tissue

• thymus

• bone marrow

• spleen

• lymph nodes

Blood plasma

• solution with ions, small molecule solutes & soluble proteins

Lymph

• fluid derived from blood and other tissues (no RBCs)

  • acc. in intercellular spaces in body

lymph nodes

• sites along lymph vessels, fluid is check for pathogen and can respond

1st line of defense (MAMMALS)

• External surfaces

  • skin,toxic molecules, pH, competetion

• mucus membranes & internalo rgans

Mucus membranes & internal organs (MAMMALS)

• mucus function

• lysozyme production

• Defensins

  • peptides inser to cell membranes → create “Free permeability”

  • toxic to bacteria, microbial EUKs, enveloped viruses

• Harsh internal Environments

lysozyme production (MAMMALS)

• mucus membranes and internal organs

• cleaves bonds in cell walls of many pathogens

2nd line of Defense (MAMMALS)

• activation of defensive cells

• recognition by specfic receptors

  • PRRs

• PAMPs

PRRs

Pattern recognition receptors

• recognize PAMPs

• mostly on phagocytic & NK cells in mammals

• TLRs are examples of PRRs

Defense second line

Complement System

• 2o different proteins circulating in blood (vertebrate)

• when activated, other downstream compliment (C) proteins are activated in sequence

  • like signal cascades

Complement system steps

1- one C protein binds to pathogen surface

• helps phagocytes recognize and destroy invading pathogens

2-Another C protein activates inflammation

• attracts phagocytes to infection site

3- other C proteins insert into pathogen membrane

• create pores, invader cell dies

cytokines

• signaling proteins

• released from PRR activation

  • inflammatory cytokines

  • interferons

    • increased resistance of neighbor cells to infection(especially viral)

    • in many vertbrates

Inflammation

• if tissue damaged - infection or injury

• isolates area to stop infection spread

• cells and m olecules recruited to site

• early reponders - mast cells release chem. signals

• pus - leaked fluid and dead cells

Early responders - mast cells, release chems that signal…

• tumor necrosis factor

• prostaglandins

• histamines

Prostaglandins

• helps with inflammation in nearby tissues

Histamines

• increases permeability of blood vessels (for WBC and molecules)

Fever

• phagocytes produce cytokines that can produce fever

  • due to pryogens

• signal brain to increase body temp

• some pathogens sensitive to temp

signal brain to increase body temp

• accelerates lymphocyte production

• increases phagocytosis

• increases metabolism —> tissue repair