Mature dendritic cells boost functionally superior CD8+ T-cell in humans without foreign helper epitopes
Madhav V. Dhodapkar, … , Ralph M. Steinman, Nina Bhardwaj
Madhav V. Dhodapkar, … , Ralph M. Steinman, Nina Bhardwaj
Published March 15, 2000
Citation Information: J Clin Invest. 2000;105(6):R9-R14. https://doi.org/10.1172/JCI9051.
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Mature dendritic cells boost functionally superior CD8+ T-cell in humans without foreign helper epitopes

Abstract

We have recently shown that a single injection of mature, antigen-pulsed, human dendritic cells (DCs) rapidly elicits CD4+ and CD8+ T-cell immunity in vivo. The DCs were pulsed with 2 foreign proteins, keyhole limpet hemocyanin (KLH) and tetanus toxoid (TT), as well as an HLA A2.1-restricted influenza matrix peptide (MP). Responses to all 3 antigens peaked at 30–90 days after immunization and declined thereafter. To determine if the foreign helper proteins (TT and KLH) were essential for CD8+ T-cell responses to the viral peptide, we reinjected 3 of the HLA-2.1 subjects with mature DCs pulsed with MP alone. All 3 volunteers showed a rapid boost in MP-specific immunity, and freshly sampled blood from 1 contained cytolytic T cells. In all 3 subjects, CD8+ T-cell responses to booster DCs were faster and of greater magnitude than the responses to the first DC injection. Importantly, the T cells that proliferated after booster DC treatment secreted interferon-γ upon challenge with much lower doses of viral peptide than those elicited after the first injection, indicating a higher functional avidity for the ligand. These data begin to outline the kinetics of T-cell immunity in response to DCs and demonstrate that booster injections of mature DCs enhance both qualitative and quantitative aspects of CD8+ T-cell function in humans.

Authors

Madhav V. Dhodapkar, Joseph Krasovsky, Ralph M. Steinman, Nina Bhardwaj

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Figure 1

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TT- and KLH-specific immunity after DC injection. (a) Longevity of KLH-s...
TT- and KLH-specific immunity after DC injection. (a) Longevity of KLH-specific immune response after single DC injection. For each measurement shown, 105 freshly isolated PBMCs were incubated in the presence or absence of 10 μg/mL KLH for 5 days, and proliferation was measured as 3H-TdR incorporation. Results are expressed as stimulation index. SEM < 30%; cpm without antigen < 5 × 103. (b) Longevity of TT-specific immune response after single DC injection. For each measurement shown, 105 freshly isolated PBMCs were incubated in the presence or absence of 3 μg/mL TT for 5 days, and proliferation was measured as 3H-TdR incorporation. Results are expressed as stimulation index. SEM < 30%. (c) Evaluation of longevity of KLH-specific response using cryopreserved specimens. Pre- and postimmunization specimens were thawed together and cultured in the presence or absence of 10 μg/mL KLH for 5 days. Antigen-specific proliferation was measured as 3H-TdR incorporation. Results are shown as stimulation index. Data shown are for 1 subject (P5), representative of 3 subjects tested. (d) Evaluation of longevity of TT- specific response using cryopreserved specimens. Pre- and postimmunization specimens were thawed together and cultured in the presence or absence of 3 μg/mL TT for 5 days. Antigen-specific proliferation was measured as 3H-TdR incorporation. Results are shown as stimulation index. Data shown are for 1 subject (P5), representative of 2 subjects tested. (e) Quantification of CD4 proliferative response as percent of CD4 blasts. T-cell cultures from the experiment in c and d were stained for CD4 and analyzed by flow cytometry. Percent of CD4 blasts were quantified as percent of CD4+ T cells with high forward scatter, noted in the upper-right quadrant. Data shown are gated for CD4+ cells. (f and g) Detection of KLH-specific antibodies. (f) Presence of KLH-specific antibodies was determined in sera before and 3 months after immunization by ELISA as described in Methods. Data shown are at a serum dilution of 1:104. Because of variable background, reactivity was assayed by comparing pre- and postimmunization samples in the same individual. All assays were repeated to verify results. *P < 0.05. (g) Representative data from a subject (A1) injected with KLH alone. KLH-specific antibodies were detected in only 1 of 7 volunteers (P4) injected with KLH-pulsed DCs. Positive control was an individual with known high-titer anti-KLH antibodies.