7.3.8 Vaccines

A vaccine is a biological preparation that provides active acquired immunity to a particular disease and resembles a disease-causing microorganism and is often made from weakened or attenuated or killed forms of the microbes, their toxins, or one of its surface proteins. Vaccines “teach” our body how to defend itself when viruses or bacteria, invade it. Vaccines deliver only very little amounts of inactivated or weakened viruses or bacteria, or parts of them. This allows the immune Antigen and Antibody interactions Neutralization (Exotoxin, toxoid) Agglutination (Particulate antigen) Virus Bacterium Bacteria Enhances Phagocytosis Inflammation Inflammation Macrophage Injury Precipitation (Soluble antigen) Antigen molecules Foreign cell Leads to Cell lysis Hole Complement molecule Complement system Fig.

. Antigen and antibody reaction