High-affinity antibodies that are protective against infection evolve from lower-affinity precursors in the germinal center (GC). This evolution is thought to occur by selective expansion of higher-affinity B cell mutants while lower-affinity ones are eliminated by apoptosis. However, the degree to which affinity-based selection restricts clonal diversity in the antibody response is unknown, as are the precise kinetics and strength of clonal evolution in GCs. Thus, we do not know how (or indeed whether) the GC generates the ideal balance between antibody affinity and clonal diversity necessary for a protective response. This parameter is important to consider when devising vaccination strategies, especially those aimed at fostering the development of rare B cell clones with ?broadly-neutralizing? potential against HIV and influenza. This gap in knowledge is largely due to our technical inability to precisely measure clonal diversity and the strength of selection over time in individual GCs. We have recently developed two microscopy-based techniques that greatly improve our ability to measure the evolution of clonal diversity during the GC response in mice: (i) multicolor fate-mapping, which relies on stochastic recombination of a ?Brainbow? allele to quantify the extent of clonal selection in individual GCs by imaging; and (ii) in situ photoactivation, which allows us to isolate hundreds of B and T cells from individual GCs by flow cytometry. We propose to use these methods to further our understanding of the role of T cell help in controlling GC clonal diversity, to understand the difference in clonal dynamics between primary and recall GCs, and to investigate the how clonal dynamics change over time in chronic GCs induced by retroviral infection. Upon fulfillment of our specific aims, we expect to have increased our understanding of how clonal competition in GCs affects the diversity and immunodominance of the antibody response. We expect that our findings will inform future vaccine development, especially against highly diverse pathogens such as HIV and influenza.

Public Health Relevance

The proposed research is relevant to public health because it addresses the question of why vaccination, which is effective against many infections, fails to induce broadly protective antibodies against HIV and influenza. We propose that understanding the competition between different antibody-producing cells may lead to answers to this question. Thus, the proposed research is relevant to the NIH's mission of developing basic knowledge that will help reduce the burden of human disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI119006-02
Application #
9406693
Study Section
Cellular and Molecular Immunology - B Study Section (CMIB)
Program Officer
Ferguson, Stacy E
Project Start
2017-01-01
Project End
2021-12-31
Budget Start
2018-01-01
Budget End
2018-12-31
Support Year
2
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Rockefeller University
Department
Microbiology/Immun/Virology
Type
Graduate Schools
DUNS #
071037113
City
New York
State
NY
Country
United States
Zip Code
10065
Jacobsen, Johanne T; Mesin, Luka; Markoulaki, Styliani et al. (2018) One-step generation of monoclonal B cell receptor mice capable of isotype switching and somatic hypermutation. J Exp Med 215:2686-2695
Pasqual, Giulia; Chudnovskiy, Aleksey; Tas, Jeroen M J et al. (2018) Monitoring T cell-dendritic cell interactions in vivo by intercellular enzymatic labelling. Nature 553:496-500
DeWitt 3rd, William S; Mesin, Luka; Victora, Gabriel D et al. (2018) Using Genotype Abundance to Improve Phylogenetic Inference. Mol Biol Evol 35:1253-1265
Degn, Søren E; van der Poel, Cees E; Firl, Daniel J et al. (2017) Clonal Evolution of Autoreactive Germinal Centers. Cell 170:913-926.e19
Ersching, Jonatan; Efeyan, Alejo; Mesin, Luka et al. (2017) Germinal Center Selection and Affinity Maturation Require Dynamic Regulation of mTORC1 Kinase. Immunity 46:1045-1058.e6