Many enzymes require a nonprotein component called apoenzyme and a protein component called cofactor to become active. Cadmium and beryllium are believed to inactivate enzymes by blocking the sites on the enzyme where such co-factors as iron normally attach. When lead covalently bonds to an enzyme, its inhibition of enzymes is considered to be irreversible. The exposure of allergens can trigger a diminished immune response in some people. Chemical pollutants such as ozone can depress the immune response by inactivating alveolar macrophages.
B cells are the principle agents in cell-mediated immunity.
Humoral immune responses are characterized by subcutaneous bleeding. The environmental pollutants such as ozone and fine particulates contribute to the significant rise in the numbers and severity of asthma cases. If absorbed, lead tends to be stored mostly in fatty tissue. Dioxin is considered to be one of the most toxic natural chemicals. List the variety of processes of absorption including their characteristics.