The secondary signal needed for T_H0 helper cells to differentiate into either T_H1 cells or T_H2 cells is the cross-link between (on TH0 helper cells) and (on APC cell).

Question

The secondary signal needed for T_H0 helper cells to differentiate into either T_H1 cells or T_H2 cells is the cross-link between ________ (on TH0 helper cells) and ________ (on APC cell).

The secondary signal needed for TH0 helper cells to differentiate into either TH1 cells or TH2 cells is the cross-link between ________ (on TH0 helper cells) and ________ (on APC cell).

The secondary signal needed for T_H0 helper cells to differentiate into either T_H1 cells or T_H2 cells is the cross-link between (on TH0 helper cells) and (on APC cell).