MHC class Ib-restricted CTL provide protection against primary and secondary Listeria monocytogenes infection.
Infection of B6 mice with the intracellular pathogen Listeria monocytogenes (LM) results in the activation of CD8(+) T cells that respond to Ag presented by both MHC class Ia and class Ib molecules. Enzyme-linked immunospot analysis reveals that these CTL populations expand and contract at different times following a primary sublethal LM infection. Between days 4 and 6 postinfection, class Ib-restricted CTL exhibit a rapid proliferative response that is primarily H2-M3 restricted. The peak response of class Ia-restricted CD8(+) T cells occurs a few days later, after the majority of bacteria have been cleared. Although class Ia-restricted CTL exhibit a vigorous recall response to secondary LM infection, we observe limited expansion of class Ib-restricted memory CTL, even in MHC class Ia-deficient mice (B6.K(b-/-)D(b-/-)). Despite this lack of enhanced expansion in vivo, class Ib-restricted memory CTL retain the ability to proliferate and expand when provided with Ag in vitro. Furthermore, we demonstrate that in vivo depletion of CD8(+) T cells in LM-immune B6.K(b-/-)D(b-/-) mice severely impairs memory protection. Together, these data demonstrate that class Ib-restricted CTL play an important role in clearing a primary LM infection and generate a memory population capable of providing significant protection against subsequent infection.
Seaman
M S
MS
Immunology Graduate Program and Center for Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA.
Wang
C R
CR
Forman
J
J
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D002460:Cell Line; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic / Q000235:genetics; D018984:Epitopes, T-Lymphocyte / Q000235:genetics / Q000276:immunology; D006183:H-2 Antigens / Q000235:genetics* / Q000276:immunology*; D006681:HLA-D Antigens / Q000235:genetics / Q000276:immunology; D000949:Histocompatibility Antigens Class II; D007117:Immunization, Secondary; D016056:Immunodominant Epitopes / Q000235:genetics / Q000276:immunology; D007156:Immunologic Memory / Q000235:genetics; D016130:Immunophenotyping; D007700:Kinetics; D008089:Listeria monocytogenes / Q000276:immunology; D008088:Listeriosis / Q000235:genetics / Q000276:immunology* / Q000517:prevention & control; D008213:Lymphocyte Activation / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology*
D018984:Epitopes, T-Lymphocyte; D006183:H-2 Antigens; C024755:H-2K(K) antigen; C032876:H-2Kb protein, mouse; C416189:H2-M antigens; D006681:HLA-D Antigens; C084245:HLA-DM antigens; D000949:Histocompatibility Antigens Class II; D016056:Immunodominant Epitopes