Immune Response Innate Immune Response - PowerPoint Presentation

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Immune Response

Innate Immune Response

The Immune System

The immune system is a group of cells & soluble molecules, which interact & distinguish patterns in the body as “self” or “non-self,” in order to eliminate those that are “non-self.”

“Non-self” entities include:

Microorganisms, transplants, tumors, foreign substances (

eg: asbestos, particulate matter)

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The Immune Response

To achieve its duty, the immune system has developed two mechanisms:

Innate immune response (IIR)

Non- specific

A

daptive immune response (AIR)Specific

Together, these two systems provide an efficient defense system

It makes it possible that although we spend our lives surrounded by germs, we sporadically get sick.

Most infections are fixed successfully by IIROther infections that IIR can not resolve, AIR will be triggered and overcome successfullyThis is followed by lasting immunological memory

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Innate Immune Response (IIR)

Is the first line

of defense in the Immune response

Crucial to control of microorganisms growing freely during early stage of IR

Lacks memoryIt is NOT

antigen (Ag) specificThere are a limited recognition moleculesLeads to the AIR

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Innate Immune Response (IIR)

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First line of defense

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IIR: External Barriers

First line of defense against pathogenic “invaders”

Skin

Largest organ in the body

Produce lactic (low pH) & fatty acids, sweat, skin oils, which make it difficult for microorganisms (MO’s) to survive

When skin is injured, protects the body by way of inflammation

Mucus

Mucosal membranes (

mb

) lining inner surfaces of the body secrete mucus, which function as protective carbohydrate layer to stop bacterial invasion

Also traps and removes bacteria & particulate matter, by complementary action of

cilliary

movement, sneezing, coughing

Body secretions

Washing actions of tears, saliva, and urine removes bacteria and foreign particles from the body

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Natural or Innate Immunity: Inflammation

When pathogenic agents penetrate external barriers, the first reaction of the body is the

inflammatory

response

Any time the cells or tissues of the body are injured, internally or on the surface, by whatever agent, the inflammatory response occursAcute Inflammatory Response occurs in blood vessels near injury

Acute Inflammatory Response helps leukocytes to leave the blood vessel (diapedesis

or emigration

) & travel to injury site via

chemotaxis8

Acute Inflammatory Response

Chemotaxis- is the movement of cells in response to a chemical attractant

Interferon

- if the cell injury is due to viral infections, interferon, a protein that protects the body against

viral infections is released

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Inflammation

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Cardinal signs of acute inflammation

Redness

HeatSwelling

PainImpairment of function (sometimes) Inflammatory mediators

Histamine

Blood proteins

Kinins, prostaglandins, leukotrienes, and complementReleased by injured tissue, phagocytes, lymphocytes, basophils, and mast cells

Acute Inflammatory Response

Complement- a complex of interrelated and interacting proteins manufactured in the liver

It is

the major

mechanism for destroying foreign substances Active in inflammation and phagocytosis and also assists the action of antibodies in the specific response if the infecting agent is not destroyed by the nonspecific defenses

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Figure 21.4, step 4

Innate

defenses

Internal

defenses

Leukocytosis.

Neutrophils enter blood

from bone marrow.

Margination

.

Neutrophils cling

to capillary wall.

Diapedesis

.

Neutrophils flatten and

squeeze out of capillaries.

Chemotaxis

.

Neutrophils

follow chemical

trail.

Capillary wall

Basement

membrane

Endothelium

Inflammatory

chemicals

diffusing

from the

inflamed site

act as chemotactic

agents.

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2

3

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Phagocytosis

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IIR: Fever

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Systemic response to invading

microorganisms

Leukocytes and macrophages exposed to foreign substances secrete

pyrogens

Pyrogens

reset the body’s thermostat

upwardHigh fevers are dangerous because heat denatures enzymesBenefits of moderate feverCauses the liver and spleen to hold iron and zinc (needed by microorganisms)Increases metabolic rate, which speeds up repair