Читать книгу Immunology - Richard Coico - Страница 48

Like other T cells defined as T_H cells, this small population of T cells express CD4 and TCRs, although with restricted variability. Unlike conventional T cells in general, natural killer (NK) T cells also express markers found on innate lymphoid cells called NK cells (see below), including CD56. In addition, unlike conventional T lymphocytes, the rearranged TCR only recognizes lipid antigens presented on CD1d, a “major histocompatibility complex (MHC)‐like molecule,” instead of MHC itself, as will be discussed in subsequent chapters.

Figure 2.10. The TCR/CD3 complex. The α and β chains of the TCR are associated with multiple CD3 dimers including εγ and εδ dimers and ζ homodimers.

Source: © John Wiley & Sons, Inc.

Table 2.1. Properties of Naïve CD4⁺ and CD8⁺ Cells

T cell	Surface phenotype	Cytokines	Transcription factors	Function
CD4+	αβ TCR, CD3, CD4, CCR7, CD62Lhi	IL‐2	THPOK	Patrol through lymph nodes scanning peptide–MHC class II molecule complexes on APCs for the presence of their cognate antigen. Following activation by APCs, naïve CD4+ T cells differentiate into effector or regulatory T cells; activated naïve T cells also give rise to memory T cells
CD8+	αβ TCR, CD3, CD8, CCR7, CD62Lhi	IL‐2	RUNX3	Patrol through lymph nodes scanning peptide–MHC class I molecule complexes for the presence of their cognate antigen. Following activation by APCs, they differentiate into CTLs and memory T cells