title: Obesity decreases B cell responses in young and elderly individuals.
abstract: OBJECTIVE
  To evaluate the effects of obesity-associated inflammation on influenza vaccine responses.
  
  
  METHODS
  In young and elderly individuals, both lean and with obesity, antibody responses to influenza vaccination were measured.
  
  
  RESULTS
  A decrease in in vivo vaccine responses, circulating switched memory, and transitional B cells and an increase in pro-inflammatory late/exhausted memory B cells were found. In vitro B cell function was measured by activation-induced cytidine deaminase and E47, markers of optimal antibody responses. Moreover, IL-6 production was increased, whereas IL-10 production was decreased in cultures of B cells from individuals with obesity. Markers of immune activation (TNF-α, TLR4, micro-RNAs) in unstimulated B cells were also found increased and were negatively correlated with B cell function. In order to reveal potential mechanisms, we stimulated B cells from lean individuals in vitro with leptin, the adipokine increased in obesity. Leptin increased phospho-STAT3, crucial for TNF-α production, and decreased phospho-AMPK, the energy sensing enzyme upstream of phospho-p38 MAPK and E47. Leptin-induced phospho-STAT3 and phospho-AMPK levels were similar to those in B cells from individuals with obesity.
  
  
  CONCLUSIONS
  These results demonstrate that leptin can be responsible for decreased B cell function in obesity.
authors: Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, USA.
authors: Daniela
authors: D
authors: Frasca
authors: Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, USA.
authors: Franco
authors: F
authors: Ferracci
authors: Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, USA.
authors: Alain
authors: A
authors: Diaz
authors: Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, USA.
authors: Maria
authors: M
authors: Romero
authors: Department of Psychiatry, University of Miami Miller School of Medicine, Miami, Florida, USA.
authors: Suzanne
authors: S
authors: Lechner
authors: Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, USA.
authors: Bonnie B
authors: BB
authors: Blomberg
mesh_terms: D000367:Age Factors; D000368:Aged; D001402:B-Lymphocytes / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000276:immunology* / Q000517:prevention & control; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D009765:Obesity / Q000276:immunology*; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines