2.2 Summary of Section 2

• The majority of present-day vaccination programmes use active vaccines containing pathogen-specific antigens to elicit a protective immune response in the recipient. Repeated vaccination enhances the effectiveness of the antibody response and (for some vaccines) also elicits cell-mediated responses.

• Passive immunisation uses antibodies raised in human donors or in horses, which are used either to treat certain life-threatening infections as soon as symptoms appear, or prophylactically to prevent infection after a known exposure.