Booster immunization with fTr (±QA) slightly enhanced the hosts' capacity to respond to challenge infection with expansion of Tc-specific antibodies than was observed in TcG2/TcG4-immunized/infected mice (Figure 2A); however, booster immunization with fTr (±QA) did not enhance the TcG2- and TcG4-specific IgGs in DNA vaccinated mice (Figures 2B,C, compare gp5 and gp6 with gp1). The gene discussed is GP6; the disease is infection.