Self/Non-Self Recognition ---一-----一-·一-一 x Immune system needs to be able to differentiate between self and non-self cells x Antigenic encounters may result in cell death therefore Some kind of positive selection Some element of negative selectionSelf/Non-Self Recognition Immune system needs to be able to differentiate between self and non-self cells Antigenic encounters may result in cell death, therefore Some kind of positive selection Some element of negative selection