Immune recognition: how do monkeys cope with pathogens?
16 September 2015
Many pathogens that cause disease in humans, can also cause disease in (rhesus) monkeys and therefore monkeys play an important role as a model-species in the search for cures against these diseases. A lot of therapies involve the stimulation of the immune system in order to eliminate the presence of the pathogens. As a consequence, knowledge of the immune system of monkeys is important for this type of work. This may also aid in the selection of a minimal number of animals for experimental purposes.
In vertebrates, including humans and monkeys, pathogens are eliminated through the action of their immune system. This highly sophisticated system has evolved to combat a wide range of pathogens. BPRC researchers have compared the immune system of rhesus monkeys and humans to provide insights into the genetic events and selective pressures that have shaped two major important gene families and were invited to publish an overview of their results in the reputed journal Immunological Reviews (http://www.ncbi.nlm.nih.gov/pubmed/26284481).
The immune system can recognize degraded segments of pathogens by specific molecules of the so-called Major Histocompatibility Complex (MHC). The MHC is a highly complex system showing a lot of variation, minimizing the possibility that an entire population is being decimated by one pathogen. In humans the specific types of MHC molecules are showing high variability, whereas in monkeys it is demonstrated that variation is achieved by the presence of different combinations of polymorphic MHC molecules. Although this illustrates that the variation is generated in two different ways, the way in which the adaptive immune response works is, however, in essence the same.
Another component of the immune system are the natural killer (NK) cells, which can, through KIR molecules present on their cell-surface, interact with the MHC and regulate the level of their activation. NK cells are important, for instance, in scanning whether pathogens have down regulated the MHC molecules of the host. The KIR system is also highly complex and involves a multitude of variants in humans and even more so in rhesus monkeys. Given the importance of combinations of MHC and KIR for reproductive success and disease outcome, careful description of these molecules in monkeys in experimental settings is necessary to monitor and understand the outcome of vaccination protocols.