A specific role for B cells in the generation of CD8 T cell memory by recombinant Listeria monocytogenes.
In this study, we investigated whether B cells play a role in the induction and maintenance of CD8 T cell memory after immunization with an intracellular bacterium, Listeria monocytogenes. Our results show that B cells play a minimal role in the initial activation and Ag-driven expansion of CD8 T lymphocytes. However, absence of B cells results in increased death of activated CD8 T cells during the contraction phase, leading to a lower level of Ag-specific CD8 T cell memory. Once memory is established, B cells are no longer required for the long-term maintenance and rapid recall response of memory CD8 T cells. Increased contraction of Ag-specific CD8 T cells in B cell-deficient mice is not due to impaired CD4 T cell responses since priming of epitope-specific CD4 T cell responses is normal in B cell-deficient mice following L. monocytogenes infection. Furthermore, no exaggerated contraction of Ag-specific CD8 T cells is evident in CD4 knockout mice. Thus, B cells play a specific role in modulating the contraction of CD8 T cell responses following immunization. Elucidation of factors that regulate the death phase may allow us to manipulate this process to increase the level of immunological memory and thus, vaccine efficacy.
Shen
Hao
H
Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. hshen@mail.med.upenn.edu
Whitmire
Jason K
JK
Fan
Xin
X
Shedlock
Devon J
DJ
Kaech
Susan M
SM
Ahmed
Rafi
R
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology* / Q000473:pathology; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000382:microbiology; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000032:analysis; D007156:Immunologic Memory / Q000235:genetics*; D008089:Listeria monocytogenes / Q000235:genetics* / Q000276:immunology*; D008088:Listeriosis / Q000235:genetics / Q000276:immunology; D008213:Lymphocyte Activation / Q000235:genetics*; D018655:Lymphocyte Count; D008212:Lymphocyte Depletion; D008231:Lymphopenia / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology
D001428:Bacterial Vaccines; D018984:Epitopes, T-Lymphocyte; D014614:Vaccines, Synthetic