Microbes (an organism too small to be seen by the naked eye) can enter the body through the mouth, nose and cuts or bites in the skin

Microbes (bacteria and viruses) can cause diseases

Two types of white blood cell:

1. Lymphocytes – engulf pathogens

2. Phagocytes – contain antibodies

White blood cells do 3 things:

1. Engulf the microbe

2. Produce antibodies to neutralise the microbe

3 Produce antitoxins to neutralise the toxins released by the microbe