title: CD69 expression as an index of T-cell function: assay standardization, validation and use in monitoring immune recovery.
abstract: BACKGROUND
  CD69 is a surrogate marker of T-cell responsiveness to mitogen and Ag stimulus and can be used as a measure of T-lymphocyte activation. Quantitative flow cytometric determination of CD69 expression on T lymphocytes has several advantages over traditional lymphocyte proliferation assays, but this method has not yet been standardized for clinical applications.
  
  
  METHODS
  We qualified a commercially available assay using the manufacturer's procedures for measurement of T-cell response to a mitogen (PHA), superantigen (Staphylococcus endotoxin B; SEB) and Ca(2+) ionophore (phorbyl myristate acetate; PMA) with peripheral blood from healthy volunteers. Following this, we tested the usefulness of the assay in determining T-cell responses to PHA and SEB for six immunocompromised patients.
  
  
  RESULTS
  Healthy volunteers showed 17-fold increases in T-cell CD69 Ab bound per cell (ABC) with PHA stimulation compared with the baseline. SEB was also an effective T-cell activating agent, increasing CD69 ABC by 5-fold, comparable with results obtained with PMA stimulation. PHA- and SEB-stimulated T-cell CD69 ABC for patients 100 days post-BM transplant were generally below 1 SD of that from healthy volunteers. SEB-stimulated T-cell CD69 expression was significantly depressed for CD8(+) T cells while CD4(+) T-cell responses to SEB were generally within 1 SD of the mean for healthy volunteers.
  
  
  CONCLUSIONS
  These results suggest that quantitative measurement of CD69 surface expression by flow cytometry is a useful diagnostic tool for detailed assessment of T-lymphocyte and subset activation.
authors: South Carolina Cancer Center, Columbia, South Carolina, USA.
authors: W B
authors: WB
authors: Lindsey
authors: M W
authors: MW
authors: Lowdell
authors: G E
authors: GE
authors: Marti
authors: F
authors: F
authors: Abbasi
authors: V
authors: V
authors: Zenger
authors: K M
authors: KM
authors: King
authors: L S
authors: LS
authors: Lamb
mesh_terms: D015703:Antigens, CD / Q000378:metabolism*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism*; D016026:Bone Marrow Transplantation; D005434:Flow Cytometry / Q000379:methods* / Q000592:standards; D006801:Humans; D016867:Immunocompromised Host / Q000276:immunology; D037181:Lectins, C-Type; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D008934:Mitogens / Q000494:pharmacology; D015203:Reproducibility of Results; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D013997:Time Factors; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D037181:Lectins, C-Type; D008934:Mitogens; D000099192:CD69 Antigens