Fish Vaccine That Triggers Cell Death to Stop Virus

Scientists studied a live fish vaccine that weakens a deadly virus in goldfish. The vaccine was made by changing the virus’s DNA. They found seven small changes, five missing pieces and one swapped section in important genes. One key change removed the start of a gene that normally stops cells from dying. In lab tests, fish cells infected with either the normal virus or the vaccine turned on genes that usually trigger cell death. The vaccine‑infected cells showed more signs of dying, like exposed phosphatidylserine and broken DNA. This means the vaccine can push cells to self‑destruct when they are infected.When goldfish received the vaccine, their tissues did not show major damage. Instead, immune cells gathered in groups and special pigment‑laden cells formed centres. The fish’s own genes for inflammation and a killer protein called granzyme B were turned up. The early cell death likely helps the fish fight off the virus. By killing infected cells quickly, the vaccine reduces how much virus can grow and spread. These findings give clues about why the virus hurts fish. They also suggest that targeting genes that control cell death could help design better vaccines for other fish viruses.