title: Regulatory T-Cell Activity But Not Conventional HIV-Specific T-Cell Responses Are Associated With Protection From HIV-1 Infection.
abstract: OBJECTIVE
  Two distinct hypotheses have been proposed for T-cell involvement in protection from HIV-1 acquisition. First, HIV-1-specific memory T-cell responses generated on HIV-1 exposure could mount an efficient response to HIV-1 and inhibit the establishment of an infection. Second, a lower level of immune activation could reduce the numbers of activated, HIV-1-susceptible CD4 T cells, thereby diminishing the likelihood of infection.
  
  
  METHODS
  To test these hypotheses, we conducted a prospective study among high-risk heterosexual men and women, and tested peripheral blood samples from individuals who subsequently acquired HIV-1 during follow-up (cases) and from a subset of those who remained HIV-1 uninfected (controls).
  
  
  RESULTS
  We found no difference in HIV-1-specific immune responses between cases and controls, but Treg frequency was higher in controls as compared with cases and was negatively associated with frequency of effector memory CD4 T cells.
  
  
  CONCLUSIONS
  Our findings support the hypothesis that low immune activation assists in protection from HIV-1 infection.
authors.affiliation: *Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA; Departments of †Global Health; ‡Epidemiology; §Medicine, University of Washington, Seattle, WA; ‖Statistical Center for HIV-1/AIDS Research and Prevention, Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA; ¶Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya; #Department of Obstetrics and Gynecology, University of Washington, Seattle, WA; **Department of Medical Microbiology, University of Manitoba, Winnipeg, Canada; ††Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya; and ‡‡Department of Pediatrics, University of Washington, Seattle, WA.
authors.forename: Laura
authors.initials: L
authors.lastname: Pattacini
authors.forename: Jared M
authors.initials: JM
authors.lastname: Baeten
authors.forename: Katherine K
authors.initials: KK
authors.lastname: Thomas
authors.forename: Tayler R
authors.initials: TR
authors.lastname: Fluharty
authors.forename: Pamela M
authors.initials: PM
authors.lastname: Murnane
authors.forename: Deborah
authors.initials: D
authors.lastname: Donnell
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Bukusi
authors.forename: Allan
authors.initials: A
authors.lastname: Ronald
authors.forename: Nelly
authors.initials: N
authors.lastname: Mugo
authors.forename: Jairam R
authors.initials: JR
authors.lastname: Lingappa
authors.forename: Connie
authors.initials: C
authors.lastname: Celum
authors.forename: M Juliana
authors.initials: MJ
authors.lastname: McElrath
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Lund
mesh_terms: D016915:AIDS Vaccines / Q000276:immunology / Q000627:therapeutic use; D000328:Adult; D000068679:Emtricitabine / Q000627:therapeutic use; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000276:immunology* / Q000517:prevention & control* / Q000821:virology; D015497:HIV-1 / Q000187:drug effects / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology*; D008297:Male; D065129:Pre-Exposure Prophylaxis; D011446:Prospective Studies; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000276:immunology*; D000068698:Tenofovir / Q000627:therapeutic use
chemical_list: D016915:AIDS Vaccines; D000068698:Tenofovir; D000068679:Emtricitabine