Biological susceptibility
The term biological susceptibility covers all phenomena that relate to the more or less specific reactivity of biological material with mostly macromolecular biotic or non-biological structures. Colloquially, the term is translated as receptivity, susceptibility or sensitivity, e.g. B. whether a host is susceptible to a certain pathogen of an infectious disease or whether a drug can work. Susceptibility is used synonymously for permissivity and is therefore the opposite of resistance . The totality of susceptible host species of onePathogen is called the host spectrum .
In a narrower sense, the term is used in connection with the description and explanation of pathogens and toxins . The individual molecular equipment for the reaction to various external noxae (e.g. bacteria , viruses , "environmental toxins") plays an important role. Knowledge of the molecular structures responsible for this is of outstanding importance both for researching the causes of diseases and for developing appropriate drugs to combat diseases. In viruses, the susceptibility of a host species or cell line is called tropism .
For the different individual susceptibility to the same noxa, u. a. the following causes of genetic origin are discussed:
- Hereditary genetic differences based on individual polymorphisms in areas of DNA that are used to code important structures such as B. specific receptors (e.g. docking sites for viruses and bacteria) or enzymes are responsible.
- Variations in the DNA repair systems due to the different sensitivity to external mutation-inducing factors.
- Differences in the regulation of gene expression , which in turn may depend on the combination of several acting toxicants.
- Restriction factors (synonym for resistance factors) that can mediate resistance to the pathogen.