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 (-5[1])requires B7 proteins (-5[1])to provide costimulatory signals that prevent incomplete activation, which can lead to anergy. (10[1])A type (10[1])of these cells begins (10[1])to express FOXP3 (-5[2])after (-5[1])receiving intermediate (10[1]-5[1])strength signals (-5[1])during (10[1])negative selection. These cells, (10[1]-5[1])which include (10[2])a “regulatory” subtype, (10[1])have receptors (10[3])that bind to (10[1])MHCs (10[1]-5[1])found on (10[1])antigen-presenting (-5[1])cells. CD4-positive (10[1])and CD8-positive (10[5])types (10[1]-5[1])of these cells, which mature in the thymus, (10[3])are respectively (10[2])known (10[1])as these cells’ helper (-5[1])and (10[2])killer (10[2])varieties. (10[3]-5[1])For 10 points, the adaptive (10[1])immune system primarily consists of B cells and what other white (10[1])blood cells? (10[1])■END■ (10[7])