Y3-Thavo3-Lesson 12 GKR

• Biologie
• Middelbare school
• havo, vwo
• Leerjaar 3

Homeostasis, Health & Disease

Lesson 12

This lesson

• Adaptive immunity
• Progress Pathogen project
  

PATHOGENS PROJECT

• How are you doing?
• Any questions so far?

Do not forget:

• Start writing your final report
• Submission date: October 25th 

Learning goals

• You know what parts belong to the adaptive immune system
• You understand what role antigen presentation plays in the adaptive immune system
• You understand how the adaptive immune system works to achieve memory
• You understand what immunity is

Keywords

• Innate immunity
• Adaptive immunity
  
• Antigen
• Foreign
• T-Lymphocyte
• B-Lymphocyte
• Antibody
• Memory cell

Innate immunesystem

Innate immunesystem:

Parts of the immune system that are present from birth

Adaptive immunesystem

Adaptive immunesystem:

Parts and processes of the immune system that are changing based on previous experiences

Lines of defence

Immune system counters attacks from pathogens in three lines of defense:

1. Barriers: keeping the pathogens out
2. Phagocytes: attacking and wiping out invaded pathogens 
3. Lymphocytes: learning from phagocytes how to specifically and effectively kill a certain type of pathogen

Lines of defence

Line 1: Barriers

Keeping pathogens out

Mechanical: Physical blockages preventing pathogens from entering the body

Chemical: Attacking pathogens by means of antimicrobial molecules

• skin
• mucosal membranes
• stomach acid
• antibacterial proteins

Line 2: Phagocytes

Phagocytes are able to perform phagocytosis and to present parts of the pathogen to the adaptive immune system

Overview of line 2

Line 1 fails: pathogens invade the body

Surviving tissue cells call for help

Macrophages start to devour pathogens and send out signs

Neutrophils arrive and join the battle. They massively kill off the pathogens and themselves

Proteins of the complement system start to kill pathogens by perforating them

Dendritic cells display parts of the pathogens on their membranes and travel to the lymph nodes

Activation of defence line 3: the adaptive immune system - the lymphocytes

Lymphatic system

Sewage system of the body

• Lymph vessels, lymph nodes, bone marrow, spleen and thymus
• drained tissue fluid is sent to lymph nodes for screening
• here the dendritic cell presents its pathogen parts (antigens)

To what part of the immune system do these lines of defence belong?

Innate immune system

Adaptive immune system

Barriers

Phagocytes

Lymphocytes

As part of innate immunity, the human body utilises mechanical and chemical immunity.
Which of the following is an example of chemical immunity?

1. Skin
2. Fluid flow in the urinary tracht
3. Stomach acid
4. Mucosal layer in the vagina

What is the main 'ingredient' of pus?

1. pathogens
2. macrophages
3. neutrophils
4. B-cells

Antigens

• Small parts coming from a pathogen
• Presented by phagocytes (dendritic cells) to lymphocytes
• Foreign vs self
• Dendritic cells present them on their surface after disassembly

Foreign vs Self

Foreign antigens
antigens that do not originate in the body themselves

Self antigens

antigens that originate in the body themselves

The adaptive immune system can distinguish between foreign and self antigens

Antigen specificity

T- and B-lymphocytes have been trained to recognize ONLY 1 antigen.

You continuously create new T- and B-lymphocytes to recognize different kinds of antigen. Even for antigens you'll never come across.

Only the T-cell that recognizes the antigen presented by the dendritic cell will become active

Antigen specificity

You have millions and millions of different lymphocytes ready to become active.

From 'naive' to 'active'

A non-active / sleeping lymphocyte is called naive. 

Antigen presentation and antigen recognition makes a lymphocyte active

antigen recognition

naive T-lymphocyte

active T-lymphocyte

T-lymphocytes get to work

Active T-lymphocyte

Division

Reactivating macrophages: start to kill pathogens

Activate specific B-cell: start to produce antibodies

B-cell

Activated T-cells activate B-cells -> production of antibodies

Naive B-cell

Active T-cell activates B-cell

Active B-cell produce  antibodies

Antibodies

• proteins produced by activated B cells
• Y-shaped
• antigen-specific
• neutralize pathogen by preventing movement and interaction

Memory cells and immunity

• A small part of the activated B- and T-cells remain present
• They turn into memory cells
• Memory B-cells produce low amounts of antibodies
• Memory T-cells keep looking for antigen

+

memory T-cells

memory B-cells

immunity

To what part of the immune system do these lines of defence belong?

Innate immune system

Adaptive immune system

Macrophage

B-Lymphocyte

T-Lymphocyte

Dendritic cell

Neutrophil

Recall from the video

WHERE in the body does this antigen presentation takes place?

1. In the infected tissue
2. in the lymph node
3. in the blood vessels
4. in your pinky toe

Recall from previous lesson/video

How is the adaptive immune system also called?

1. specific immune system
2. aspecific immune system
3. innate immune system
4. barrier system

Recall from the video:

What is the first thing that happens after T-cell* activation?

* T-lymphocyte = T-cell

1. making worn-down macrophages active again
2. activating B-cells
3. dividing
4. having a glass of beer

Fill the gaps in the text:

__1__ are present on the surface of pathogens. As a response from B cells __2__ are produced to neutralise the __3__

1. 1 = antibodies 2 = antigens 3 = pathogens
2. 1 = antigens 2 = pathogens 3 = antibodies
3. 1 = pathogens 2 = antigens 3 = antibodies
4. 1 = antigens 2 = antibodies 3 = antigens

A COVID quick test is an example of an antigen test.

This test proves the presence of ... ?

1. the virus
2. macrophages
3. antibodies
4. an active adaptive immune system

Well done!

You now understand how the adaptive immune system works.

To summarise: watch the same video again on the next slide and you will see you know understand the immune system a lot better !

Learning goals

• You know what parts belong to the adaptive immune system
• You understand what role antigen presentation plays in the adaptive immune system
• You understand how the adaptive immune system works to achieve memory
• You understand what immunity is

Keywords

• Innate immunity
• Adaptive immunity
  
• Antigen
• Foreign
• T-Lymphocyte
• B-Lymphocyte
• Antibody
• Memory cell

A concept map

A concept map adds descriptions to links between two terms

Homework

• Complete this LessonUp
• Read pages 147-148 in the book (use the pdf on the classroom)
• Complete the Assignments on lesson 5 on the classroom