Skip to main content
. Author manuscript; available in PMC: 2021 Jun 2.
Published in final edited form as: Sci Transl Med. 2020 Dec 2;12(572):eaaz2253. doi: 10.1126/scitranslmed.aaz2253

Figure 2.

Figure 2

The host immune response and regenerative medicine. (A) Direct allorecognition occurs by cytotoxic T cells (Tc cells) recognizing and eliminating allogeneic donor cells, while indirect allorecognition occurs by helper T cells (Th cells) recognizing donor antigens taken up and displayed by host antigen-presenting cells. (B) Implanted biomaterials can provoke a foreign body reaction resulting in the formation of a fibrous capsule containing both macrophages and foreign body giant (FBG) cells. (C) An example of immune evasion, in which transgene expression and CRISPR/Cas9 are used to generate hypoimmunogenic hiPSCs with upregulated CD47 but neither class of MHC (B2m-/- and Ciita-/-). (D) An example of immune modulation, in which ECM-derived biomaterials recruit T helper 2 cells (Th2 cells), which secrete cytokines that can polarize macrophages to an M2-like phenotype. In turn, these alternatively-activated macrophages secrete cytokines that sustain Th2 cell activation.