Utilizing the combined actions of HBV-specific CD4+ T-cells [essential for the induction and the maintenance of both CD8+ T-cells and antibody responses (67, 68)] and HBV-specific CD8+ T-cells [which kill infected hepatocytes and induce local production of proinflammatory cytokines (69–71)], a healthy person can easily overcome acute HBV infection, and thus avoid the chronic and life-threatening phase of the infection. This evidence concerns the gene CD4 and infection.