B1b lymphocytes confer T cell-independent long-lasting immunity

Immunity. 2004 Sep;21(3):379-90. doi: 10.1016/j.immuni.2004.06.019.

Abstract

Many microbial pathogens employ antigenic variation as a strategy to evade the immune system, posing a challenge in vaccine development. To understand the requirements for immunity against such pathogens, we studied Borrelia hermsii, a relapsing fever bacterium. We found that mice deficient in T, follicular B, marginal zone B, or B1a lymphocytes resolved B. hersmii bacteremia and became resistant to reinfection. The resolution of bacteremia coincided with an expansion and persistence of B1b lymphocytes, and purified B1b lymphocytes from convalescent wild-type or TCR-betaxdelta-/- mice conferred immunity to Rag1-/- mice. The B1b lymphocytes in the reconstituted Rag1-/- mice provided long-lasting immunity by rapidly generating B. hermsii-specific IgM but not IgG upon bacterial challenge. Unmutated IgM is sufficient to eliminate B. hermsii, because AID-/- mice deficient in somatic hypermutation and class switch recombination efficiently resolved all bacteremic episodes. These data demonstrate that B1b lymphocytes can provide long-lasting T cell-independent IgM memory.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adoptive Transfer
  • Animals
  • Antigens, T-Independent / immunology*
  • B-Lymphocytes / immunology*
  • Borrelia Infections / immunology*
  • Enzyme-Linked Immunosorbent Assay
  • Flow Cytometry
  • Immunoglobulin M / blood
  • Immunologic Memory*
  • Mice

Substances

  • Antigens, T-Independent
  • Immunoglobulin M