Tuesday, September 24, 2013

NIAID-DVI: B-cell responses to dengue infection -- Jens Wrammert

Blog Series: NIAID-DVI

Human B cell responses during dengue infection
Jens Wrammert
Emory University

"Humoral immune responses are thought to play a major role in dengue-induced immuno-pathology, however little is known about the plasmablasts producing these antibodies during an ongoing infection." ~Jens
  •  The group analyzed plasmablast responses in patients with acute dengue infection.
    • plasmablast responses increased more than 1000 fold over baseline levels.
    • These responses made up as much as 30% of the peripheral lymphocyte population
    • Responses were dengue specific
      • IgG secreting cells that reached high numbers after fever onset coinciding with 'the window' where serious dengue-induced pathology is observed.
 
What is a plasmablast?
"The most immature blood cell that is considered a plasma cell instead of a B cell is the plasmablast. Plasmablasts secrete more antibodies than B cells, but less than plasma cells. They divide rapidly and are still capable of internalizing antigens and presenting them to T cells. A cell may stay in this state for several days, and then either die or irrevocably differentiate into a mature, fully differentiated plasma cell." ~Wikipedia
"A plasmablast is basically a B cell that is actively secreting antibodies. This is in response to acute infection only so it is not 'long term' "~Dr. Friberg-Robertson, Immunologist and Friend Extraordinaire 
Questions raised:
Do these cells have a role in dengue immuno-pathology during an ongoing infection?
Ongoing/Future Research to answer said question:
  • Understanding the complete repertoire and specificity of the antibodies that are secreted [en masse] by the plasmablasts.
  • Jens' group has/is generated panels of human monoclonal antibodies from dengue infection-induced plasmablasts for 5 patients and have done initial functional analyses...stay tuned into his research for the results.
Other papers that highlight plasmablast responses in dengue infection: