title: High CD99 expression in memory T and B cells in reactive lymph nodes.
abstract: We investigated the expression of CD99 in 35 hyperplastic perigastric lymph nodes, which were resected for gastric carcinoma or chronic peptic ulcer. Essentially, all lymphocytes in lymph nodes expressed CD99, but there were two populations with respect to the intensity of CD99 expression--CD99high and CD99low cells. We showed CD99high cells were distributed in paracortical and medullary cords by immunohistochemical study while germinal center cells were CD99low. Using three-color flow cytometric analysis with CD3, CD4, CD8, CD19, CD23, CD45RA, CD45RO, CD69, CD138, IgM, IgD, and IgG, most of CD99high cells were shown to be activated/memory T cells. CD4+CD45RO+ T cells were the subset revealing the highest intensity of CD99 expression while CD4+CD45RA+ T cells were CD99low. Among B cells, IgG+ B cells revealed a higher level of CD99 molecules than IgM+ B cells. These results suggest that CD99 is one of activation-related molecules which are upregulated in recently activated lymphocytes.
authors.affiliation: Department of Pathology, Sungkyunkwan University School of Medicine, Suwon, Korea.
authors.forename: C K
authors.initials: CK
authors.lastname: Park
authors.forename: Y K
authors.initials: YK
authors.lastname: Shin
authors.forename: T J
authors.initials: TJ
authors.lastname: Kim
authors.forename: S H
authors.initials: SH
authors.lastname: Park
authors.forename: G H
authors.initials: GH
authors.lastname: Ahn
mesh_terms: D000071443:12E7 Antigen; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis*; D001402:B-Lymphocytes / Q000276:immunology*; D015815:Cell Adhesion Molecules / Q000032:analysis*; D005434:Flow Cytometry; D018858:Germinal Center / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D007156:Immunologic Memory / Q000276:immunology*; D008198:Lymph Nodes / Q000276:immunology*; D008875:Middle Aged; D010437:Peptic Ulcer / Q000276:immunology*; D013274:Stomach Neoplasms / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules