Specificity, restriction and effector mechanisms of immunoregulatory CD8 T cells

• Published in: Immunology 2001-02, Vol.102 (2), p.115-122
• Main Authors: Vukmanovic‐Stejic, M., Thomas, M. J., Noble, A., Kemeny, D. M.
• Format: Article
• Language: English
• Subjects: Animals; CD8 antigen; CD8-Positive T-Lymphocytes - immunology; Humans; Immune Tolerance; Immunoglobulin E - biosynthesis; Inflammation - immunology; Lymphocyte Cooperation - immunology; Mice; Rats; Review; Th1 Cells - immunology; Th2 Cells - immunology
• ISSN: 0019-2805; 1365-2567
• DOI: 10.1046/j.1365-2567.2001.01193.x

A number of groups have demonstrated that human, murine and rat CD8 T cells have the potential to produce a much wider array of cytokines than was initially thought. Moreover, CD8 T cells appear to differentiate in a polarized fashion and can be divided into subsets analogous to those described for CD4 T cells. These subsets were termed type 1 or Tc1 and type 2 of Tc2. However, while in the CD4 cells, different cytokine profiles were closely associated with specific functions, i.e. T helper type 1 (Th1) cells were inflammatory T cells, while T helper type 2 (Th2) cells were helpers for antibody production, a correlation between cytokine profile and function has yet to be clearly defined for CD8 T cells. Furthermore it is difficult to associate the newly described CD8 T-cell subsets with phenomena of immune suppression. However, as some CD8 T cells produce potent immunoregulatory cytokines such as interleukin-4 (IL-4). IL-10 and transforming growth factor- beta (TGF- beta ), it is likely they may play a role in immune regulation including suppression. In addition, more and more evidence has emerged indicating that CD8 T cells have the capacity to regulate both the induction and effector phases of the immune response through their secreted products or through direct interaction with other cells. Here, we review evidence, old and new, for the capacity of CD8 T cells to influence the outcome of numerous immune responses.