Arising in the mucous membranes, these white patches on the tongue, gums, cheeks, or elsewhere inside the mouth have the potential to develop into squamous cell carcinoma. They may be caused by sources of chronic irritation, such as habitual alcohol consumption or tobacco use, or rough edges on teeth or dentures.
Virus infection in vertebrates results in two general types of immune response. The first is a rapid-onset innate response against the virus, which involves the synthesis of proteins called interferons and the stimulation of natural killer lymphocytes.
Cells of the innate system respond to pathogens in a very general, generic way. Their response does not change, regardless of the type of pathogen involved. Another key feature of the innate immune response is that it has no memory, and it cannot trigger the development of memory. The innate response is, in evolutionary terms, a much older defense system than the adaptive response â plants, fungi, insects, and more primitive multicellular organisms have innate immune defense systems.