title: Further characterization of memory T cells existing in a case of CD8 deficiency.
abstract: CD8 deficiency is a rare primary immunodeficiency caused by a defect of ZAP-70, which plays a pivotal role in T cell activation. We previously reported the existence of memory phenotype-CD4+ T cells in a case of CD8 deficiency, which demonstrates that activation signals through ZAP-70 are not essential to the phenotypic conversion of T cells from "naive" to "memory." In this study, we further characterized CD45RO+ T cells in a CD8 deficient patient. We showed that the patient's CD45RO+ T cell population had a wide variety of T cell receptor Vbeta-chain gene usage, and contained few clonally expanded T cells, while many clonally expanded T cells were present in the memory T cell population of age-matched healthy children. These results suggest that various kinds of antigens were involved in the differentiation of the patient's T cells, and that the differentiation into memory T cells was not accompanied by profound T cell proliferation. Moreover, our findings confirmed that the patient's CD45RO+CD4+ T cells had acquired effector-cytokine producing ability, indicating that there exists an alternative activation pathway which is independent of ZAP-70 for the acquisition of effector-cytokine producing ability.
authors.affiliation: Department of Pediatrics, Central Clinical Laboratory, Kyoto University Hospital, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ueno
authors.forename: K
authors.initials: K
authors.lastname: Katamura
authors.forename: T
authors.initials: T
authors.lastname: Yorifuji
authors.forename: K
authors.initials: K
authors.lastname: Ohmori
authors.forename: T
authors.initials: T
authors.lastname: Kiyomasu
authors.forename: J
authors.initials: J
authors.lastname: Iio
authors.forename: K
authors.initials: K
authors.lastname: Ohmura
authors.forename: M
authors.initials: M
authors.lastname: Mayumi
mesh_terms: D016827:CD8 Antigens / Q000378:metabolism*; D002454:Cell Differentiation; D016207:Cytokines / Q000096:biosynthesis; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D007156:Immunologic Memory; D007223:Infant; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008213:Lymphocyte Activation; D008297:Male; D011505:Protein-Tyrosine Kinases / Q000172:deficiency / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000473:pathology; D051746:ZAP-70 Protein-Tyrosine Kinase
chemical_list: D016827:CD8 Antigens; D016207:Cytokines; D016693:Receptors, Antigen, T-Cell, alpha-beta; D011505:Protein-Tyrosine Kinases; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human; D017493:Leukocyte Common Antigens