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…)
There are thousands of components to the immune system, and during the course of learning about some of these it can appear tha ...
Most initial infections are local, i.e. the infectious agent gains entry to the body at a single site, e.g. via an insect bite ...
There are several pathogen types that can cause disease include many groups of single-celled microorganisms and larger multicel ...
Routes by which infectious organisms gain entry into the body include the skin, respiratory tract, gastro-intestinal (GI) tract ...
Exotoxins are secreted products, usually of bacteria but sometimes protozoa and fungi. They can act in a number of ways: • ...
Bacteria cause allergic disease because of toxicity, invasiveness, immunopathology, or lends of these three mechanisms. Thus much of the interaction between a given bacterial species and the cellular immune response can be predicted by considering the immunological mechanisms available in relation to the mechanism of pathogenicity, and the structure of the bacterium. For a toxigenic bacterium, neutralizing antigen & antibody may be all that is needed. Otherwise destruction of the organism itself may be required. (more…)
One especially favored target for immune recognition is bacterial lipopolysaccharide (LPS). This macromolecule is found only in ...
Exotoxins are noxious proteins secreted by many bacteria. These toxins are often heat-labile and thus can be heat-inactivated f ...
Innate immune responses are seen in a very broad range of tissues. Indeed, the Toll-like receptors (TLRs, one of the most important ...
An especially elaborate and important type of innate antimicrobial enzymes defense is provided by a group of serum proteins tha ...
Once it is tethered onto the venule wall, the neutrophil or other leukocyte comes into contact with a wide variety of inflammatory ...