Immune responses that should combat a disease caused by yeast instead make the fungus grow, potentially worsening the infection.

Robin May at the University of Birmingham, UK, and his co-workers studied strains of Cryptoccocus gattii, which can cause meningitis and other problems.

They found that oxygen-containing molecules produced by the host as a defence mechanism cause some of the fungal cells to become quiescent and resist immune responses. The remaining cells proliferate quickly, resulting in an overall increase in cell numbers. The resistant cells contained energy-producing organelles called mitochondria that were tubular in shape.

The findings suggest that the fungal cells act as a team during infection, with non-dividing cells helping neighbouring ones to grow rapidly.

Nature Commun. 5, 5194 (2014)