Scientific Publications by FDA Staff

Infect Immun 2008 May;76(5):2177-82

Anamnestic Protective Immunity to Bacillus anthracis is Antibody-mediated but Independent of Complement and Fc Receptors.

Harvill ET, Osorio M, Loving CL, Lee GM, Kelly VK, Merkel TJ

Merkel, TJ (reprint author), US FDA, Ctr Biol Evaluat & Res, DBPAP, Lab Resp & Special Pathogens, Bldg 29,Rm 418,29 Lincoln Dr, Bethesda, MD 20892 USA US FDA, Ctr Biol Evaluat & Res, DBPAP, Lab Resp & Special Pathogens, Bethesda, MD 20892 USA Penn State Univ, Dept Vet & Biomed Sci, University Pk, PA 16802 USA

The threat of bioterrorist use of Bacillus anthracis has focused urgent attention on the efficacy and mechanisms of protective immunity induced by available vaccines. However, the mechanisms of infection-induced immunity have been less well-studied and defined. We used a combination of complement depletion along with immunodeficient mice and adoptive transfer approaches to determine the mechanisms of infection-induced protective immunity to B. anthracis. B- or T-cell-deficient mice lacked the complete anamnestic protection observed in immunocompetent mice. In addition, T-cell deficient mice generated poor antibody titers but were protected by the adoptive transfer of serum from B. anthracis challenged mice. Adoptively transferred sera were protective in mice lacking complement, Fc receptors or both, suggesting that they operate independent of these effectors. Together these results indicate that antibody-mediated neutralization provides significant protection in B. anthracis infection-induced immunity.