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Antigen Processing Takes a New Direction
- Goonetilleke, Nilu, McMichael, Andrew J.
- Science 2013 v.340 no.6135 pp. 937-938
- T-lymphocytes, antigen-presenting cells, cytokines, epitopes, genetic engineering, glycoproteins, major histocompatibility complex, receptors, secretion, vaccines
- T lymphocytes expressing αβ T cell receptors can be divided into those that express either CD8 or CD4 glycoproteins on their cell surface. Major histocompatibility complex (MHC) molecules on antigen-presenting cells present small fragments of antigenic proteins (epitopes) to T cells, and here again is a distinction: MHC class I (MHC-I) present to CD8 ⁺ T cells, whereas MHC class II (MHC-II) present to CD4 ⁺ T cells. Classical CD8 ⁺ T cells kill target cells, whereas CD4 ⁺ T cells exhibit effector and regulatory functions through cytokine secretion. On page 940 of this issue, Hansen et al. (1) challenge these paradigms of T cell antigen recognition and function and raise the possibility of achieving distinct T cell responses through the genetic manipulation of vaccine vectors.