Microbial Pathogenesis: Secretation of Toxins, Endotoxins and Killing of Host Cells

microbial pathogenesis
The final stage of the disease process (although it may not be the final stage of the infection) is the actual production of disease. Many microorganisms live in or on the body without causing disease. These organisms are called commensal organisms and may be beneficial to the host: the production of lactic and lactobacilli proprionic acidophilus in the vagina inhibits the growth of many other bacteria and many commensal organisms compete with pathogens for ‘living space’ in the gut. Microbial pathogens differ in that they cause dis- ease by one or more mechanisms like picture bellow. These include the following: (more…)

Allergen Exposure And The Development Of Atopic Sensitization

There is much controversy as to the role of allergen exposure for the development of atopic sensitization towards this allergen. While in some studies, a clear, almost linear dose-response relation between allergen exposure and sensitization has been found, others described a bell-shaped association with higher levels of exposures relating to lower rates of atopic sensitization. Part of the discrepancy may relate to the type of allergen, since mostly cat but not house dust mite allergy allergen exposure has been shown, in some studies, to exert protective effects at higher levels of exposure. (more…)

Endotoxins and Exotoxins

endotoxins and exotoxins
Exotoxins are noxious proteins secreted by many bacteria. These toxins are often heat-labile and thus can be heat-inactivated for use as vaccines to prevent toxigenic immunity to bacteria disease. Many bacteria produce more than one protein exotoxin, making vaccine development more difficult. (more…)