1. Clonal selection and expansion of specific T cells and B cells
2. Synthesis of antibodies
Antibodies do not begin to appear in the blood until roughly 10 to 17 days after the foreign antigen first entered the body
This time delay is why we often experience symptoms of a disease when we are first exposed to a pathogen
Clonal expansion of T and B cells
Form memory cells
Memory cells
Can last for many years and often a lifetime
Form the basis of immunological memory
Secondary immune response
1. B memory cells recognise the antigen
2. B memory cells divide quickly and differentiate into plasma cells and more memory cells
3. More memory cells can be selected and more antibodies produced quickly
Secondary immune response
Extremely fast compared to primary immune response
Secondary immune response
T memory cells (helper and killer) become active quickly
Immunological memory (made possible by memory cells) is the reason why catching certain diseases twice is so unlikely
Some infections such as the common cold and influenza are caused by viruses that are constantly developing into new strains, so the primary immune response must be carried out each time before immunity can be achieved
