Germination

Cancer

CTL*

Cytotoxic T cell

In vitro

Immunology

T cell

Immunotherapy

Dendritic cell

Cancer immunotherapy

Cancer research

Genetics

Biochemistry

Botany

Medicine

Priming (agriculture)

Biology

Immune system

Nature reviews. Immunology

Cancer immunotherapy aims to promote the activity of cytotoxic T lymphocytes (CTLs) within a tumour, assist the priming of tumour-specific CTLs in lymphoid organs and establish efficient and durable antitumour immunity. During priming, help signals are relayed from CD4+ T cells to CD8+ T cells by specific dendritic cells to optimize the magnitude and quality of the CTL response. In this Review, we highlight the cellular dynamics and membrane receptors that mediate CD4+ T cell help and the molecular mechanisms of the enhanced antitumour activity of CTLs. We outline how deficient CD4+ T cell help reduces the response of CTLs and how maximizing CD4+ T cell help can improve outcomes in cancer immunotherapy strategies. CD4+ T cells provide help to CD8+ T cells via lymph node-resident dendritic cells. In this Review, the authors discuss the molecular nature of help signals and how they can be harnessed to improve cancer immunotherapy.

CD4+ T cell help in cancer immunology and immunotherapy