Antigen-Independent Selection of T15 Idiotype During B-Cell Ontogeny in Mice

Academic Article

Abstract

  • Precursors of B cells capable of responding to a T-independent form of phosphorylcholine (PC) in splenic focus assays were detected in the spleens of neonatal mice as early as 4 days after birth. The earliest anti-PC B cells were T15-. T15+ foci-forming B cells were first detected 6 days after birth and expanded rapidly to constitute greater than 80% of the total PC-specific foci by day 10. Injection of heat-killed S. pneumoniae (R36A) into neonatal mice resulted in priming of the antibody response to PC, with an idiotype profile reflecting that of precursors of foci-forming B cells at the time of antigen administration. Priming of 2-day- old mice with 2 ×106 and 2 ×107 R36A induced a five- and ten-fold increase in the antibody response to phosphorylcholine 6 to 8 weeks later. However, only 10 to 15% of the serum antibodies expressed the normally dominant T15 idiotype. Doses below 2 ×105 R36A showed no detectable priming activity. PC-specific hybridomas derived from mice injected with 2 ×107 R36A 2 days after birth lacked the idiotypic and molecular characteristics typical of T15+ antibodies. Antibodies to phosphorylcholine, raised by immunization of 6-week-old mice are normally protective against pneumococcal infection. However, serum antibodies from mice treated with R36A 2 days after birth and responding to phosphorylcholine following challenge with R36A at 6 weeks of age failed to protect against deliberate infection with virulent S. pneumoniae. These observations imply that the antigen phosphorylcholine does not play a role in the selective expansion and dominant expression of the T15 idiotype. © 1991, Harwood Academic Publishers GmbH.
  • Published In

  • Autoimmunity  Journal
  • Digital Object Identifier (doi)

    Pubmed Id

  • 6161231
  • Author List

  • Vakil M; Briles DE; Kearney JF
  • Start Page

  • 203
  • End Page

  • 212
  • Volume

  • 1
  • Issue

  • 3