Question 1 (actual word count 610) By Brian Maunder.
Do vaccines produce active or passive immunity? Explain your answer. Why is passive immunity less satisfactory?.
The immune system, is a functional system that defends the body against invading infectious pathogens. It consists of an army of specialised leukocytes including phagocytic cells (macrophages, neutrophils), "Natural Killer- cells and lymphocytes, who battle pathogens on a home playing field equipped with an array of chemical weaponry including antibodies, compliment, interferons, cytokines and more ( Marieb 2001:793-795 ) (Crisp & Taylor 2001: 842) (Myers 2001:611). This army can develop specific pathogen destroying techniques when previously trained for the battle. This is achieved either naturally through illness, or artificially through vaccines (Wendell Richmond 1997).
Vaccines stimulate the immune system to produce its own antibodies for the particular introduced antigens. In effect it causes active immunity (Minnet, Wayne & Rubenstein 1989:176).
If an organism successfully penetrates non-specific defences such as skin and mucous membranes, they are initially bombarded by a plethora of non-specific defensive mechanisms. These can include fever, inflammatory responses, antimicrobial proteins, compliment and attacking phagocytes, most noticeably, macrophages (derived from monocytes) (Marieb 2001: 794-800) (Crisp & Taylor 2001: 841). These macrophages help form a sentinel network "always on the lookout for foreign antigens- (Lee & Bishop 2002: 187). If an antigen is recognised as non-self, phagocytic cells including macrophages engulf the particle, triggering the primary immune response which helps set up a specific immune defence against the encountered antigen (Miller and Keane 1983:565) (Smeaten 2003). This defence can consist of either, or a combination of, a humoral response or a cell mediated response (Wendell Richmond 1997).
