Studying fungal infection in zebrafish larvae, researchers found that macrophages don't kill Aspergillus spores directly. Instead, these immune cells release reactive molecules that block spores from sprouting into invasive threads. The fungus fights back with melanin, a pigment that shields it from this attack.
Aspergillus fumigatus causes serious infections in people with weakened immune systems, such as transplant and chemotherapy patients. This work pinpoints where the immune fight actually happens: not at killing spores, but at stopping their growth into invasive threads. That clarifies which stage of infection decides whether disease takes hold.
✦ Sometimes the immune system wins not by killing a fungus, but by keeping it from growing.