Immune surveillance

Biology

Patrolling

Endocrinology

Political science

Immunology

Immunity

Cell biology

Platelet activation

Vascular wall

Immune system

Platelet

Nature reviews. Immunology

Platelets are small anucleate cellular fragments that are released by megakaryocytes and safeguard vascular integrity through a process termed ‘haemostasis’. However, platelets have important roles beyond haemostasis as they contribute to the initiation and coordination of intravascular immune responses. They continuously monitor blood vessel integrity and tightly coordinate vascular trafficking and functions of multiple cell types. In this way platelets act as ‘patrolling officers of the vascular highway’ that help to establish effective immune responses to infections and cancer. Here we discuss the distinct biological features of platelets that allow them to shape immune responses to pathogens and tumour cells, highlighting the parallels between these responses. Platelets are best known for their roles in haemostasis, but they also contribute to host immunity. In this Review, Gaertner and Massberg consider how platelets ‘patrol the vascular highway’ to shape immune responses during infection and cancer.

Patrolling the vascular borders: platelets in immunity to infection and cancer