Components of Bordetella pertussis that are important in the organism's ability to cause disease include: (1) tracheal cytotoxin that destroys cilia, making it difficult to clear thickened mucus; (2) pertussis toxin (also called lymphocytosis-promoting factor), which interferes with immune cell function, contributes to ciliary damage, and aids attachment to respiratory epithelium; (3) filamentous hemagglutinin, which helps the bacteria attach to cilia of the respiratory tract; (4) pertactin (also called 69 kilodalton protein), which also aids bacterial attachment to cilia; and (5)
agglutinogens, which may aid persistent attachment to cilia.
The A and B antigens are inherited as Mendelian dominants, and individuals are divided into four major blood types on the basis of the presence of
agglutinogens. Type A individuals have the A antigen, Type B have the B, Type AB have both, and Type O have neither.
Agglutination occurs when antibodies (also called agglutinins) cross-link with insoluble antigens (also called
agglutinogens) to form visible clumps (Figure 2-12A).
Potential vaccine-target antigens important in disease production include (1) pertussis toxin (lymphocytosis-prorooting factor), which interferes with immune-cell function, contributes to ciliary damage, and aids in attachment to respiratory epithelium; (2) filamentous hemagglutinin, which helps the bacteria attach to cilia of the respiratory tract; (3) pertactin (69-kDa protein), which also enhances bacterial attachment to cilia; and (4)
agglutinogens, which may aid persistent attachment to cilia.