Quantitation of CD8+ T Cell Expansion, Memory, and Protective Immunity After Immunization with Peptide-Coated Dendritic Cells

Abstract

Dendritic cells (DCs) are potent APCs for naive CD8+ T cells and are being investigated as vaccine delivery vehicles. In this study, we examine the CD8+ T cell response to defined peptides from Listeria monocytogenes (LM), lymphocytic choriomeningitis virus, and murine CMV coated singly and in combination onto mature bone marrow-derived DCs (BMDCs). We show that immunization of mice with 2 × 105 mature BMDCs coated with multiple MHC class I peptides generates a significant Ag-specific CD8+ T cell response in both the spleen and nonlymphoid organs. This immunization resulted in a peptide-specific hierarchy in the magnitude of CD8+ T cell priming and noncoordinate kinetics in response to different peptide epitopes. Kinetics were not exclusively due to specific characteristics of the MHC class I molecule, and were not altered in an Ag-independent manner by concurrent LM infection. Mice immunized with listeriolysin O 91–99-coated BMDCs are protected against high dose challenge with virulent LM. This protection was enhanced by diversifying the memory CD8+ T cell compartment, even in the absence of a large increase in Ag-specific CD8+ memory T cells.

CD8 T cell competition for dendritic cellsin vivois an early event in activation

“…We cannot rule out a soluble factor such as a cytokine as the limiting factor in competition, and there is clearly an upper limit to the expansion of T cell precursors in a given immune response that is not caused by DC availability (4,5,40,41). However, in this and other published reports of competition between T cells of different specificities, the competition was alleviated or eliminated when antigen was provided on separate DCs (2,6,7,10,42). Such competition may limit the efficacy of multivalent vaccines that deliver multiple CD8 T cell epitopes simultaneously, and care must be taken in the design of such vaccines to maintain as broad of an immune response as possible.…”

Regulation of CD8+ T Cells Undergoing Primary and Secondary Responses to Infection in the Same Host

“…7A). One day later, the recipient mice were immunized with 2.5 ϫ 10 5 LLO 91-99 -coated CD11c ϩ DC (22). In repeated experiments, the peak of the expansion of LLO 91-99 -specific CD8 ϩ T cells, for primary and secondary responses, was day 5 postimmunization (Fig.…”

“…Thus, it is possible that the nature of the APC dictates the program of contraction. To address this issue, we activated primary and secondary CD8 ϩ T cell responses in the same host by immunization with peptide-coated DC (22) and followed the kinetics of contraction.…”

“…CD11c ϩ BMDC were generated as previously described (22). Briefly, RBC-depleted BALB/c (H-2 d ) bone marrow was subjected to complement depletion after incubation with mAbs anti-CD8 (3.168), anti-I-A d (34-5-3), anti-CD4 (RL172), anti-B220/CD45R (RA3-3A1/6.1), and anti-Ly6G (RB6-8C5).…”

Cutting Edge: Differential Self-Peptide/MHC Requirement for Maintaining CD8 T Cell Function versus Homeostatic Proliferation

“…DCs were generated from B6 or TAP Ϫ/Ϫ bone marrow and matured with LPS in vitro as described previously (21). DCs were coated with 1 M peptide consisting of aa 257-264 of hen egg OVA (ova [257][258][259][260][261][262][263][264] ) for 1 h and washed three times.…”