Pertussis, also known as the whooping cough, is a highly contagious disease caused by the bacterium Bordetella pertussis. Despite generally high coverage with the DTP and DTaP vaccines, pertussis is one of the leading causes of vaccine-preventable deaths world-wide. Ninety percent of all cases occur in the Third World. It is transmitted by airborne infection. B. pertussis vaccine was first developed in 1920 using whole bacterium. In 1942, the whole-cell pertussis vaccine was combined with diphtheria and tetanus toxoids to generate the first DTP combination vaccine. Whole cell vaccines have some side effects. Acellular pertussis vaccine consisting of purified haemagglutinins (HAs: filamentous HA and leucocytosis- promoting-factor HA), which are secreted by B. pertussis into the culture medium are being using alone or in combination with DTaP (aP represents acellular vaccine). The introduction of acellular pertussis (Pa) vaccines in countries with a low uptake of whole-cell pertussis (Pw) vaccines has led to a dramatic reduction in pertussis disease. Those with three or more components consisting of filamentous hemagglutinin (FHA), pertussis toxin (PT) and pertactin (PRN) are considered to be more effective than one/two-component Pa vaccines that contain only PT or both PT and FHA. Pertactin (PRN or p69 protein) is a highly immunogenic virulence factor of Bordetella pertussis, a bacterium that causes pertussis. Specifically, it is an outer membrane protein that promotes adhesion to tracheal epithelial cells. PRN is purified from Bordetella pertussis and is used for the vaccine production as one of the important components of acellular pertussis vaccine. Pertactin domains are common components of the excreted portion of bacterial autotransporter proteins. The domain is made up of a beta helix of variable length. P.69 is produced as a large (910aa) precursor molecule. It is proteolytically processed at its N and C termini to produce P.69 and P.30, which are located at the cell surface and in the outer membrane, respectively. P.69 contains the amino acid triplet arginine-glycine-aspartic acid (RGD), a sequence motif which functions as a cell-binding site in a number of mammalian proteins, and it has been shown that the P.69 RGD sequence is also involved in adherence to host cells . Like P.69, pertussis toxin is excreted and may be found loosely associated with the outer membrane. Pertussis toxin has numerous biological activities and probably plays a role in hampering the host immune response.