T-Cell $\alpha \beta ^{+}$ and $\gamma \delta ^{+}$ Deficient Mice Display Abnormal but Distinct Phenotypes toward a Natural, Widespread Infection of the Intestinal Epithelium

• Published in: Proceedings of the National Academy of Sciences - PNAS 1996-10, Vol.93 (21), p.11774-11779
• Main Authors: Roberts, Scott J., Smith, Adrian L., West, A. Brian, Wen, Li, Findly, R. Craig, Owen, Michael J., Hayday, Adrian C.
• Format: Article
• Language: English
• Subjects: Adoptive Transfer; Animals; Bleeding; Blood; CD4-Positive T-Lymphocytes - immunology; Coccidiosis - genetics; Coccidiosis - immunology; Coccidiosis - pathology; Coinfection; Eimeria - immunology; Eimeria - isolation & purification; Epithelial cells; Gastrointestinal Hemorrhage - genetics; Gastrointestinal Hemorrhage - immunology; Immunity; Infections; Intestinal Diseases - immunology; Intestinal Diseases - parasitology; Intestinal Diseases - pathology; Intestinal Mucosa - parasitology; Intestinal Mucosa - pathology; Intestine, Small - immunology; Intestine, Small - pathology; Lymph Nodes - immunology; Lymphocyte Transfusion; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Mice, Knockout; Oocysts; Phenotype; Receptors, Antigen, T-Cell, alpha-beta - genetics; Receptors, Antigen, T-Cell, gamma-delta - genetics; T cell antigen receptors; T lymphocytes; T-Lymphocytes - immunology
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.93.21.11774

Vertebrate immune systems contain T cells bearing either $\alpha \beta $ or $\gamma \delta $ T-cell antigen receptors (TCRs). $\alpha \beta $ T cells perform all well-characterized T-cell effector functions, while the biological functions of $\gamma \delta ^{+}$ cells remain unclear. Of particular interest is the role of $\gamma \delta ^{+}$ cells during epithelial infections, since $\gamma \delta ^{+}$ cells are commonly abundant within epithelia. Eimeria spp. are intracellular protozoa that infect epithelia of most vertebrates, causing coccidiosis. This study shows that in response to Eimeria vermiformis, mice lacking $\alpha \beta $ T cells display defects in protective immunity, while mice lacking $\gamma \delta ^{+}$ cells display exaggerated intestinal damage, apparently due to a failure to regulate the consequences of the $\alpha \beta $ T cell response. An immuno-downregulatory role during infection, and during autoimmune disease, may be a general one for $\gamma \delta ^{+}$ cells.