immune response. vocabulary immunology- the study of host defense mechanisms immunity- ability of...

25
Immune Response

Upload: alexia-robbins

Post on 22-Dec-2015

222 views

Category:

Documents


1 download

TRANSCRIPT

Page 1: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

Immune Response

Page 2: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

2

Vocabulary Immunology- the study of host defense mechanisms

Immunity- ability of the host to protect itself against foreign organisms. Resistance to disease.

Antigen (Ag)- is a foreign substance that can elicit specific immune response (IR) when is immunogenic

Antibody (Ab)- protein produced by the body’s immune system when it detects harmful substances called antigens

White blood cells (leukocytes)- chief function is to protect the body against microorganisms causing disease and fight infection when it occurs. They are bigger than red blood cells.

Page 3: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

3

White Blood Cells (WBC) 5 Major types of WBC

Neutrophils Eosonophils Basophils Lymphocytes (T and B Cells) Monocytes

Divided into two categories Granuolocytes and Agranuolocytes

Page 4: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

4

Granuolocytes Neutrophils

are the most common WBC in peripheral blood. Circulate in blood 7-10 hrs before migrating into

tissue Live only a few days “front line of innate defense” Increased # used as an indicator of infection Extravasate in inflammation rxn Active phagocytes

Page 5: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

5

Granuolocytes Eosonophils

Function in phagocytosis

Account for less than 5% of WBC

Increased # often present in patients with parasitic infections or allergies

Basophils Rarest WBC in blood Non phagocytic Function as “sirens”

for inflammation and allergy

Page 6: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

6

Agranuolocytes Lymphocytes

Cornerstone of the immune system Much smaller than the 3 granuolocytes Help provide a specific response to attack the

invading organisms Are formed in lymphatic tissue throughout the

body Two types of lymphocytes

T cells and B cells, which differ in function and the molecules that are on their surface also differs

Page 7: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

7

Agranuolocytes Lymphocytes

T cells Circulate through they thymus gland and have turned

into cells known as thymocytes When exposed to antigens, they rapidly divide and

produce large number of new T cells that are sensitive to that type of antigen

More than 80% of lymphocytes circulating in the body are T cells

Divided into 2 main groups “killer cells” because they produce chemical substances

that are essential in helping the B cells destroy foreign substances

Helper T cells which assist the “killer cells” in performing their activities and help protect the body against diseases in other ways

Page 8: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

8

Agranuolocytes Lymphocytes

B cells Circulate in the blood in an immature way About 10% that circulate the blood are B cells Produce proteins known as antibodies

Antibodies attach to foreign pathogens in the body known as antigens that are found on the surface of certain microorganisms

When B cells divide they produce an identical copies of antibodies on their surface

Page 9: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

9

Agranuolocytes Monocytes

Largest WBC found in the blood Originate in the bone marrow Play important role in the inflammatory response Present pieces of pathogens to T cells so that

pathogens may be recognized and killed Leave the blood stream to become macrophages As a monocyte or macrophage, these cells are

phagocytic (engulfing) and defend the body against viruses and bacteria

Page 10: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

10

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)

Page 11: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

11

The Immune Response Natural or Innate Immunity (IIR)

Non-specific

Acquired or Adaptive Immunity (AIR) Specific

Page 12: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

12

The Immune Response To achieve its duty, the immune system has

developed two mechanisms: innate immune response (IIR) & adaptive immune response (AIR). 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 IIR, other

that IIR can not resolve, AIR is triggered and overcome successfully, followed by lasting immunological memory

Page 13: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

13

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 memory It is not antigen (Ag) specific There are a limited recognition molecules Leads to the AIR

Page 14: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

14

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

Page 15: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

15

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 occurs Acute Inflammatory Response (AIR)- occurs in

blood vessels near injury AIR helps leukocytes to leave the blood vessel

(diapedesis or emigration) & travel to injury site via chemotaxis

Page 16: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

16

Acute Inflammatory Response Chemotaxis- is the movement of cells in

response to a chemical attractant In the inflammatory response, chemicals called

mediators, lure the leukocytes to the inflammatory site, where they release enzymes and begin the process of phagocytosis (engulfing and destroying foreign particles or organisms) Histamine was the first chemical identified as a mediator

of the inflammatory response Interferon- if the cell injury is due to viral

infections, interferon, a protein that protects the body against viral infections is released

Page 17: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

17

Acute Inflammatory Response Complement- a complex of interrelated and

interacting proteins manufactured in the liver Active in inflammation and phagocytosis and also

assists the action of antibodies in the specific response in the infecting agent is not destroyed by the nonspecific defenses

Page 18: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

18

Phagocytosis

Page 19: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

19

Adaptive or Acquired Immune Response

Everyone is born with natural immunity to disease, but we can also acquire immunity to disease

Acquired immunity can be acquired naturally or artificially, and it can be active or passive

Page 20: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

20

Acquired or Adaptive Immune Response

Refers to antigen specific defense mechanisms that take several days to become protective and are designed to react with and remove specific antigens

This immunity is developed throughout life

Page 21: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

21

Acquired or Adaptive Immune ResponseThere are two major branches of the adaptive immune response

Humoral Antibody- mediated

immune response Mediated by B-

lymphocytes

Cellular Cell-mediated

immune response Involves the

production of cytotoxic T- lymphocytes, activated macrophages, activated NK cells, and cytokines in response to an antigen

Mediated by T-lymphocytes

Page 22: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

22

Acquired or Adaptive Immune Response During adaptive immunity:

Bone marrow & thymus (primary lymphoid tissues) produce B cells and T cells, respectively

Immature T cells migrate to thymus and become competent T cells

B cells and T cells recirculate through spleen and lymph nodes (secondary lymphoid tissues)

Antigen (Ag) presenting cells (APC) pick up antigen and migrate to secondary lymphoid tissues & interact with T cells and B cells

Page 23: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

23

Antigen Processing and Presentation In order to generate adaptive immunity, as

well as long lasting memory, Ag should be recognized by T and B cells Memory usually improves upon repeated exposure

to a given infection

Page 24: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

24

Acquired ImmunityType of Immunity How acquired by Host Examples

Active Immunity Occurs when an individual is exposed to an infectious agent or one of its products (antigens)

Active Natural Immunity: Antibodies are produced by the host in response to the infectious agent itself (e.g. Recovery from disease)

Active Artificial Immunity: Occurs through vaccination with a form of the disease microorganism. It may be dead, attenuated (weakened), or altered so that it will not produce the disease but will cause the body to produce antibodies.

Passive Immunity

As a result of acquisition of antibodies which have been produced by another animal (by active means) or derived from cells grown in tissue culture

Passive Natural Immunity: Transfer of antibodies from a mother to her baby through the placenta; Transfer of antibodies from mother to infant in milk if nursing.

Passive Artificial Immunity: Acquired through inoculation with antibodies. Injection of immune serum from an individual previously immunized or recovered from disease

Page 25: Immune Response. Vocabulary  Immunology- the study of host defense mechanisms  Immunity- ability of the host to protect itself against foreign organisms

25

Differences in Innate and Adaptive Immunity The innate and adaptive immune responses both

function to protect against invading organisms, but they differ in a number of ways

(1) The innate immune system is constitutively present and reacts immediately to infection. The adaptive immune response to an invading organism takes some time to develop

(2) The innate immune system is not specific in its response and reacts equally well to a variety of organisms, whereas the adaptive immune system is antigen-specific and reacts only with the organism that induced the response

(3) The adaptive immune system exhibits immunological memory. It "remembers" that it has encountered an invading organism (antigen) and reacts more rapidly on subsequent exposure to the same organism. The innate immune system does not possess a memory.