The antibody responses of aged animals and humans may change in the magnitude and/or in the structure of antibody molecules. The long-term objective of this proposal is to elucidate the mechanisms of those immunological changes, and their effects on the ability of aged individuals to resist infections, using an experimental model of mouse antibody response against S. pneumonia strain R36a (Pn). The Pn-antibody response, which is directed against the immunodominant bacterial epitope, phosphorylcholine (PC), protects the mice against lethal infection with pneumococci. The PC antibody molecules produced by young/adult mice (2-6 mo. age) are encoded by a single combination of V (D) J genetic segments designated as T15 genes. Surprisingly, the antibody produced by aged (>20 mo old) mice may be quite robust, but it appears to be encoded by different germline Ig genes. The first proposed aim is to determine as to how many different V gene families encode the H and L chains of Pc-specific hybridomas Ab generated from aged mice. Selected VH (V-D-J) regions will be sequenced to asses the extent of somatic mutations, in comparison with similar genes from young Mab. The effects of genetic shift on the specificity and antipneumococcal activity of aged PC-antibody will be determined in both active and passive protection experiments. Subsequent aims are on the mechanisms of age-related antibody repertoire shift. An adoptive transfer of purified lymphocytes will be used to determine whether the aged pre-B cells develop into different PC-reactive clones, alone or whether the shift is influenced by the aged T cells. The competence of aged T cells to regulate the magnitude and the diversity of antibody response to PC antigens will be studied both in vitro and in thymic mice reconstituted with T cell subsets from young and aged donors. The proposed studies will determine whether (a) the aged CD4+ cells fail to drive the formation of germinal centers as well as the somatic diversification of the antibody repertoire, and (b) the magnitude of PC response in age mice is determined by the genetic make-up o the host via a mechanism related to T cells.

National Institute of Health (NIH)
National Institute on Aging (NIA)
Research Program Projects (P01)
Project #
Application #
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Han, Shuhua; Yang, Kaiyong; Ozen, Zeynep et al. (2003) Enhanced differentiation of splenic plasma cells but diminished long-lived high-affinity bone marrow plasma cells in aged mice. J Immunol 170:1267-73
Dal Porto, Joseph M; Haberman, Ann M; Kelsoe, Garnett et al. (2002) Very low affinity B cells form germinal centers, become memory B cells, and participate in secondary immune responses when higher affinity competition is reduced. J Exp Med 195:1215-21
Davila, M; Foster, S; Kelsoe, G et al. (2001) A role for secondary V(D)J recombination in oncogenic chromosomal translocations? Adv Cancer Res 81:61-92
Lu, Y F; Singh, M; Cerny, J (2001) Canonical germinal center B cells may not dominate the memory response to antigenic challenge. Int Immunol 13:643-55
Chen, Z; Koralov, S B; Kelsoe, G (2000) Regulation of humoral immune responses by CD21/CD35. Immunol Rev 176:194-204
Chen, Z; Koralov, S B; Kelsoe, G (2000) Complement C4 inhibits systemic autoimmunity through a mechanism independent of complement receptors CR1 and CR2. J Exp Med 192:1339-52
Takahashi, Y; Cerasoli, D M; Dal Porto, J M et al. (1999) Relaxed negative selection in germinal centers and impaired affinity maturation in bcl-xL transgenic mice. J Exp Med 190:399-410
Yang, K; Davila, M; Kelsoe, G (1999) Do germinal centers have a role in the generation of lymphomas? Curr Top Microbiol Immunol 246:53-60;discussion 61-2
Song, H; Nie, X; Basu, S et al. (1999) Regulation of VH gene repertoire and somatic mutation in germinal centre B cells by passively administered antibody. Immunology 98:258-66
Dal Porto, J M; Haberman, A M; Shlomchik, M J et al. (1998) Antigen drives very low affinity B cells to become plasmacytes and enter germinal centers. J Immunol 161:5373-81

Showing the most recent 10 out of 24 publications