title: Decay kinetics of HIV-1 specific T cell responses in vertically HIV-1 exposed seronegative infants.
abstract: OBJECTIVE
  The majority of infants born, in developed countries, to HIV-1 positive women are exposed to the HIV-1 virus in utero or peri/post-partum, but are born uninfected. We, and others, have previously shown HIV-1 specific T cell responses in HIV-1 exposed seronegative (HESN) neonates/infants. Our objective in this study was to examine the rate of decay in their HIV-1 specific T cell response over time from birth.
  
  
  METHODS
  Cross-sectional and longitudinal studies of HIV-1 specific T cell responses in HESN infants were performed.
  
  
  METHODS
  Peripheral blood mononuclear cells (PBMC) were isolated from 18 HIV-1 DNA PCR negative infants born to HIV-1 infected mothers receiving care at the Jacobi Medical Center, Bronx, NY, USA. PBMC were examined for T cell responses to HIV-1 antigens by interferon-gamma (IFN-γ) ELISPOT.
  
  
  RESULTS
  PBMC from 15 HESN neonates/infants were analyzed. We observed a decay of HIV-1 specific T cell responses from birth at a rate of -0.599 spot forming unit/10⁶ cells per day, with a median half-life decay rate of 21.38 weeks (13.39-115.8).
  
  
  CONCLUSIONS
  Our results support the dynamic nature of T cell immunity in the context of a developing immune system. The disparate rate of decay with studies of adults placed on antiretroviral drugs suggests that antigen specific T cell responses are driven by the natural rate of decay of the T cell sub-populations themselves.
authors.affiliation: Division of Experimental Medicine, Department of Medicine, San Francisco General Hospital, University of California San Francisco San Francisco, CA, USA.
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Holditch
authors.forename: Emily M
authors.initials: EM
authors.lastname: Eriksson
authors.forename: Leandro F
authors.initials: LF
authors.lastname: Tarosso
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kuebler
authors.forename: Esper G
authors.initials: EG
authors.lastname: Kallas
authors.forename: Erik K
authors.initials: EK
authors.lastname: Nielsen
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Wiznia
authors.forename: Michael G
authors.initials: MG
authors.lastname: Rosenberg
authors.forename: Douglas F
authors.initials: DF
authors.lastname: Nixon