The main role of the immune system is to protect the organism against damage by ensuring an adequate response against various pathogens such as viruses, bacteria, fungi, parasites, environmental harm stimuli including allergens, haptens and also from damage that may result from inappropriate immune system activation.
The immune system, therefore, has to comprise mechanisms that maintain homeostasis, including both activatory and inhibitory mechanisms. CD200 and CD200R, type I transmembrane-anchored glycoproteins, are structurally similar to immunoglobulins. CD200/CD200R interaction is crucial inhibitory immune system in alternative activation of microglia (M2). However, the role of CD200/CD200R interaction during alternative activation of microglia has not been described yet. Foxp3 is one of the most important transcriptional repressor and inhibits activation pro-inflammatory system. We examined the expression of Foxp3 in kainic acid (KA)-induced neurodeneration of the mouse hippocampus and Foxp3 is co-expressed with CD200R, it suggests that Foxp3 is related with alternative activation of microglia. We suggest that Foxp3 may regulate alternative activation of microglia through CD200/CD200R interaction.