Changes

* Immune deviation/suppression

* Immune deviation/suppression

===Ignorance===

'''Ignorance''' can occur when self-reactive T cells cannot penetrate an endothelial barrier, when self-antigen is present in very low amounts, when self-antigen is present on cells that do not express or express low amounts of MHC or when self-antigen is presented without co-stimulation, which can lead to ignorance or anergy, depending on the type of antigen and the affinity to the TCR. Ignorance also occurs when the T cells are not present in sufficient numbers to mount an effective response.

Can occur if;

* Self-reactive T cells cannot penetrate an endothelial barrier

* Self-antigen is present in very low amount

* Self-antigen is present on cells that do not express/express low amount of MHC

* Self-antigen is presented without co-stimulation- can lead to ignorance or anergy, depending on type of antigen and affinity to TCR

===Anergy===

===Anergy===