Furthermore, recent animal studies using a woodchuck model have shown promise for immunotherapeutic strategies targeting the PD-1 pathway as an adjunct to vaccination; PD-1 blockade in combination with both entecavir and DNA vaccination increased virus-specific T cell function associated with anti-woodchuck hepatitis surface antibodies and viral eradication in some animals [25]. The gene discussed is PDCD1; the disease is hepatitis A virus infection.