Module 2:

Defence Mechanisms

This module is quite large and complex. It covers pathogens as an antigen source and discusses the first line of defence followed by the non-specific and specific immune response. This module is expected to take up 6-8 hours of class time.


VCE Biology(2017-2021)

Unit 3, Area of Study 2, Outcome 2, VCE Biology Study Design

Key knowledge:

Responding to antigens

  • invading cellular and non-cellular pathogens as a source of non-self antigens, and preventative strategies including physical, chemical and microbiological barriers in animals and plants that keep them out
  • the characteristics and roles of components (macrophages, neutrophils, mast cells, dendritic cells, complement proteins) of the innate (non-specific) immune response to an antigen including the steps in the inflammatory response
  • the characteristics and roles of components of the adaptive (specific) immune response including the actions of B lymphocytes and their antibodies (including antibody structure) in humoral immunity, and the actions of T helper and T cytotoxic cells in cell-mediated immunity


6-8 hours

Student learning outcomes

Upon completion of this module students will:

  • state and explain the difference between cellular and non-cellular pathogens as a source of antigens
  • list the components and the steps in the immune response
  • describe and explain the first, second and third lines of defence
  • describe the production of antibodies

Teacher background information



Self vs. non-self immunity (14:28)

This video gives a detailed description of how B-cells and T-cells distinguish between self and non-self. It also gives an example of an autoimmune disease towards the end of the clip.

Web page

Antigens and their role in disease

This page gives very clear definitions of antigens and their role in disease. There is a descriptive paragraph on each of the cellular and non-cellular agents.

Web page


Another easy to understand diagram and explanation of cellular and non-cellular pathogens.

Web page and short video

Immune Cells

The National Institute of Allergy and Infectious Diseases explaining cells and their function in the immune response. There is also a short (0:24) video clip of a neutrophil swarm.


Phagocytosis (2:05)

Animation and explanation of phagocytosis

Web page

First line of defence

The first line of defence in animals and plants. This website is easy to understand. Information is displayed in dot points rather than slabs of text.

Web page

Second line of defence

The second line of defence. This page has diagrams and scaffolds knowledge from other units within VCE Biology.

Web page

Third line of defence

This page covers the third line of defence with some great diagrams.


The Immune Response (2:30)

Web page

Immune response

This web page gives a detailed description of the immune response. There are also some diagrams which may be useful.


International Day of Immunology (pdf)

This booklet gives a broad overview of all things immunology. Pages 9-12 give great descriptions of the components involved in the immune response.


Unlocking the Secrets of the Immune System with Professor James McCluskey (5.55)

This short podcast highlights the work carried out by Prof. McCluskey's team on the specific immune response focussing on dendritic cells.


How the Immune System Works (pdf)

This publication has been put together by the US Department of Health and Human Services. It is a well written easy to understand document on how the immune system works.

Book chapter

Chapter 1, The Immune System 4th Ed (pdf)

This first chapter of this book by Peter Parham gives a very detailed overview of the immune system. Of particular note is Figure 1.12 on page 13. The figure gives a nice diagram and description of cells involved in the immune response. At the end of the chapter there are also some review questions that may be of use.


Wikibooks: Human Physiology/The Immune System

Whilst the detail provided here, goes into too much depth, there are three possibly useful points about this resource. The first being the analogy of the immune system as a castle, the review questions towards the end of the section and the glossary at the end.


Teaching sequence



As a class construct an animation on the key focus points of the 1st, 2nd and 3rd lines of defense.

Video and review questions

This is a short video on phagocytosis followed by 5 multiple choice questions to test knowledge and understanding

Online quiz

This is a 10 question quiz that tests the students’ knowledge on the immune system

Online courses

There are a three Active Immunity online courses that are 20-30 minutes in duration

You will need to register and create a login for this site.

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Thanks to the following for contributing to the development of these sequences:

Special thanks to Ian Bentley and Mary Vamvakas