IB Biology Topic C3.2.8 Activation of B-lymphocytes by Helper T-lymphocytes Revision Notes (SL/HL)

IB Biology Topic C3.2.8 Activation of B-lymphocytes by Helper T-lymphocytes Revision Notes (SL/HL) | RevisionDojo

Written by official IB examiners

A B-cell needs a helper T-cell signal as well as its antigen to be activated

Definition

Helper T-lymphocytes

A type of T lymphocyte (T cell) that helps activate B cells by providing necessary signals once both cells have recognized the same antigen.

Recognising its antigen is not enough on its own to activate a B-cell.
The B-cell also needs a signal from a helper T-lymphocyte.

Analogy

The helper T-cell acts like a commander that confirms the threat.
Only then does the B-cell, the weapon maker, get the order to respond.

An antigen-presenting cell displays pathogen fragments to helper T-cells

A macrophage or dendritic cell engulfs a pathogen and breaks it into fragments.
It displays these fragments on its surface using MHC proteins.
This antigen-MHC complex is ready to be read by a helper T-cell.

Analogy

The antigen-presenting cell is like a detective holding up evidence to alert the rest of the team.

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Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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A B-cell needs a helper T-cell signal as well as its antigen to be activated

Definition

Helper T-lymphocytes

A type of T lymphocyte (T cell) that helps activate B cells by providing necessary signals once both cells have recognized the same antigen.

Recognising its antigen is not enough on its own to activate a B-cell.
The B-cell also needs a signal from a helper T-lymphocyte.

Analogy

The helper T-cell acts like a commander that confirms the threat.
Only then does the B-cell, the weapon maker, get the order to respond.

An antigen-presenting cell displays pathogen fragments to helper T-cells

A macrophage or dendritic cell engulfs a pathogen and breaks it into fragments.
It displays these fragments on its surface using MHC proteins.
This antigen-MHC complex is ready to be read by a helper T-cell.

Analogy

The antigen-presenting cell is like a detective holding up evidence to alert the rest of the team.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic C3.2.8: Activation of B-lymphocytes by Helper T-lymphocytes Notes

A B-cell needs a helper T-cell signal as well as its antigen to be activated

An antigen-presenting cell displays pathogen fragments to helper T-cells

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

A B-cell needs a helper T-cell signal as well as its antigen to be activated

An antigen-presenting cell displays pathogen fragments to helper T-cells

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics