title: Functional integrity of the CD28 co-stimulatory pathway in T lymphocytes from elderly subjects.
abstract: BACKGROUND
  the antigen CD28, expressed in most T cells, has co-stimulatory properties and plays a pivotal role in clonal T cell anergy mechanisms.
  
  
  METHODS
  we have compared proliferative T cell responses after anti-CD3 or in phorbol myristate acetate activation with concomitant CD28 signal in peripheral blood mononuclear cells from healthy donors aged over 65 [elderly donors; ED] and young healthy donors (YD); mean age 30+/-2.7 years).
  
  
  RESULTS
  no proliferative responses were observed in ED and YD with anti-CD28 monoclonal antibody alone. These responses both were defective in ED, particularly after anti-CD3 monoclonal antibody stimulus (7604 compared with 12,438 c.p.m. in YD, P=0.001) and were corrected when anti-CD28 monoclonal antibody was added to the culture (17,216 vs 18,536, not significant). Functional integrity of the CD28 co-stimulatory pathway was demonstrated by analysis of CD25 expression, interleukin-2 secretion and interleukin-2 gene expression on T cells from ED and YD. Age-associated phenotypic T cell changes were not crucial for an adequate CD28 response.
  
  
  CONCLUSIONS
  these experiments demonstrate the integrity of the CD28 pathway in elderly people, and suggest that ageing does not affect different T cell activation pathways equally.
authors.affiliation: Services of Geriatrics, Hospital Clínico San Carlos, Madrid, Spain.
authors.forename: M T
authors.initials: MT
authors.lastname: Vidán
authors.forename: B
authors.initials: B
authors.lastname: Fernández-Gutiérrez
authors.forename: C
authors.initials: C
authors.lastname: Hernández-García
authors.forename: J A
authors.initials: JA
authors.lastname: Serra
authors.forename: J M
authors.initials: JM
authors.lastname: Ribera
authors.forename: M
authors.initials: M
authors.lastname: Pérez-Blas
authors.forename: J R
authors.initials: JR
authors.lastname: Regueiro
authors.forename: A
authors.initials: A
authors.lastname: Bañares
authors.forename: J A
authors.initials: JA
authors.lastname: Jover
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000276:immunology; D018106:CD28 Antigens / Q000378:metabolism*; D002455:Cell Division; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D007376:Interleukin-2 / Q000235:genetics / Q000378:metabolism; D008297:Male; D008934:Mitogens / Q000494:pharmacology; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic
chemical_list: D018106:CD28 Antigens; D007376:Interleukin-2; D008934:Mitogens; D015375:Receptors, Interleukin-2; D013755:Tetradecanoylphorbol Acetate