Pertussis toxin they are formed from two subunits. The "A" subunit possesses enzyme activity, and is transferred to the host cell following a conformational change in the membrane-bound transport "B" subunit. Pertussis toxin is an exotoxin with six subunits (named "S1" through "S5"—each complex contains two copies of "S4"). The subunits are arranged in "A-B" structure: the "A" component is enzymatically active and is formed from the S1 subunit, while the "B" component is the receptor-binding portion and is made up of subunits S2–S5. The subunits are encoded by "ptx" genes encoded on a large PT operon that also includes additional genes
Rh disease Rh disease Rh disease (also known as rhesus isoimmunisation, Rh (D) disease, rhesus incompatibility, rhesus disease, RhD hemolytic disease of the newborn, rhesus D hemolytic disease of the newborn or RhD HDN) is a type of hemolytic disease of the newborn (HDN). The disease ranges from mild to severe, and typically occurs only in some second or subsequent pregnancies of Rh negative women where the fetus's father is Rh positive, leading to a Rh+ pregnancy. During birth, the mother may be exposed to the infant's blood, and this causes the development of antibodies, which may affect the health of subsequent