Acquired, but not innate, immune responses to Streptococcus pneumoniae are compromised by neutralization of CD40L

Academic Article


  • Streptococcus pneumoniae is a significant pathogen of young children and the elderly. Systemic infection by pneumococci is a complex process involving several bacterial and host factors. We have investigated the role of CD40L in host defense against pneumococcal infection. Treatment of mice with MR-1 antibody (anti-CD154/CD40L) markedly reduced antibody responses to the pneumococcal protein PspA, elicited by immunization of purified protein or whole bacteria. In mice immunized with whole bacteria, MR-1 treatment reduced antibody responses to capsular polysaccharides but not cell wall polysaccharides. MR-1 did not suppress antibody responses to isolated capsular polysaccharides but did reduce the production of antibody to a capsular polysaccharide-protein conjugate, indicating that when presented in the context of whole bacteria, the humoral response to capsular polysaccharides is partially T-cell dependent. Despite the reduction of the protective humoral responses to pneumococcal infection, administration of MR- 1 had no effect on sepsis, lung infection, or nasal carriage in nonimmune mice inoculated with virulent pneumococci. Thus, short-term neutralization of CD40L does not compromise innate host defenses against pneumococcal invasion.
  • Published In

    Digital Object Identifier (doi)

    Pubmed Id

  • 7038114
  • Author List

  • Hwang YI; Nahm MH; Briles DE; Thomas D; Purkerson JM
  • Start Page

  • 511
  • End Page

  • 517
  • Volume

  • 68
  • Issue

  • 2