How does activation of the adaptive immune system affect immunotherapeutic targeting in pediatric oncology?

Updated: Mar 20, 2018
  • Author: Crystal L Mackall, MD; Chief Editor: Jennifer Reikes Willert, MD  more...
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The adaptive (acquired) immune system is composed of T cells and B cells that undergo specific recognition of foreign antigens and generate immunologic memory.

T cells are lymphoid cells that are generated in the bone marrow but undergo maturation in the thymus. They only recognize foreign peptides when presented with a self-major histocompatibility complex (MHC) molecule; this interaction is the first signal needed to activate a T cell. These cells also require stimulation by a second signal, a costimulatory molecule provided by professional antigen-presenting cells (APCs)—typically dendritic cells (DCs)—which instruct T cells to become activated against antigens expressed in the milieu.

In this regard, researchers have designed vaccines that provide these 2 signals to target a tumor-associated antigen. Other than their direct cytotoxic effects against tumors, T cells can also secrete various cytokines that recruit other components of the immune system.

B cells are lymphoid cells that serve as professional APCs but also secrete antibodies in response to a foreign antigen. Generation of monoclonal antibodies against tumor-associated antigens and receptor tyrosine kinases has led to various targeted therapies that have improved tumor responses even in tumors that failed conventional therapies.

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