The density of two types of these cells forms the basis of a classification scheme proposed by Jérôme Galon, which ranges from I0 to I4 and may outperform traditional TNM staging. A type of these cells requires B7 proteins to provide costimulatory signals that prevent incomplete activation, which can lead to anergy. (10[1])A type of these cells begins to express FOXP3 after receiving intermediate strength signals (-5[1])during negative selection. These cells, which include (10[1])a “regulatory” subtype, have receptors that bind to (10[1])MHCs found on antigen-presenting cells. CD4-positive and CD8-positive (10[2])types of these cells, which mature in the thymus, are respectively known (10[1])as these cells’ helper and killer varieties. (10[1])For 10 points, the adaptive immune system primarily consists of B cells and what other white blood cells? ■END■