Beryllium-specific CD4+ T cells induced by chemokine neoantigens perpetuate inflammation
Michael T. Falta, Jeremy C. Crawford, Alex N. Tinega, Laurie G. Landry, Frances Crawford, Douglas G. Mack, Allison K. Martin, Shaikh M. Atif, Li Li, Radleigh G. Santos, Maki Nakayama, John W. Kappler, Lisa A. Maier, Paul G. Thomas, Clemencia Pinilla, Andrew P. Fontenot
Michael T. Falta, Jeremy C. Crawford, Alex N. Tinega, Laurie G. Landry, Frances Crawford, Douglas G. Mack, Allison K. Martin, Shaikh M. Atif, Li Li, Radleigh G. Santos, Maki Nakayama, John W. Kappler, Lisa A. Maier, Paul G. Thomas, Clemencia Pinilla, Andrew P. Fontenot
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Research Article Pulmonology

Beryllium-specific CD4+ T cells induced by chemokine neoantigens perpetuate inflammation

Abstract

Discovering dominant epitopes for T cells, particularly CD4+ T cells, in human immune-mediated diseases remains a significant challenge. Here, we used bronchoalveolar lavage (BAL) cells from HLA-DP2–expressing patients with chronic beryllium disease (CBD), a debilitating granulomatous lung disorder characterized by accumulations of beryllium-specific (Be-specific) CD4+ T cells in the lung. We discovered lung-resident CD4+ T cells that expressed a disease-specific public CDR3β T cell receptor motif and were specific to Be-modified self-peptides derived from C-C motif ligand 4 (CCL4) and CCL3. HLA-DP2–CCL/Be tetramer staining confirmed that these chemokine-derived peptides represented major antigenic targets in CBD. Furthermore, Be induced CCL3 and CCL4 secretion in the lungs of mice and humans. In a murine model of CBD, the addition of LPS to Be oxide exposure enhanced CCL4 and CCL3 secretion in the lung and significantly increased the number and percentage of CD4+ T cells specific for the HLA-DP2–CCL/Be epitope. Thus, we demonstrate a direct link between Be-induced innate production of chemokines and the development of a robust adaptive immune response to those same chemokines presented as Be-modified self-peptides, creating a cycle of innate and adaptive immune activation.

Authors

Michael T. Falta, Jeremy C. Crawford, Alex N. Tinega, Laurie G. Landry, Frances Crawford, Douglas G. Mack, Allison K. Martin, Shaikh M. Atif, Li Li, Radleigh G. Santos, Maki Nakayama, John W. Kappler, Lisa A. Maier, Paul G. Thomas, Clemencia Pinilla, Andrew P. Fontenot

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Figure 8

LPS increased chemokine/Be-specific CD4+ T cells and inflammation in BeO-exposed HLA-DP2 Tg mice.

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LPS increased chemokine/Be-specific CD4+ T cells and inflammation in BeO...
(A) CCL4 (left) and CCL3 (right) measured by ELISA (pg/ml) in the BAL fluid of FVB/N HLA-DP2 Tg mice. After standard sensitization with BeO, mice were boosted on day 14 with either BeO (n = 5) or BeO plus LPS (10 μg; n = 5) and sacrificed 24 hours later. (B) Frequency of Be-specific CD4+ T cells at day 21 in the lungs of PBS- (n = 4), BeO- (n = 5), and BeO/LPS-treated (n = 5) HLA-DP2 Tg mice measured by IFN-γ (left) and IL-2 (right) ELISPOT is shown. Data are expressed as the mean ± SEM spot-forming units per 4 × 104 cells. (C) Shown are the frequency (left) and total number (right) of HLA-DP2–CCL4/Be tetramer staining CD4+ T cells isolated from the lungs of PBS- (n = 4), BeO (n = 5), and BeO/LPS-treated mice (n = 5) sacrificed on day 21. (D) Flow cytometric density plots illustrating representative HLA-DP2–CCL4/Be tetramer staining of lung cells derived from PBS- (left), BeO- (middle), and BeO/LPS-exposed (right) HLA-DP2 Tg mice sacrificed on day 21. (E) Frequency of HLA-DP2–plexin A/Be tetramer staining CD4+ T cells from the lungs of mice treated as indicated (PBS, n = 4; BeO, n = 5; BeO/LPS, n = 5). (F) Representative H&E staining of lungs from BeO-treated (upper panels) and BeO/LPS-treated (lower panels) mice showing mononuclear cell infiltrates at low and higher magnification. (G) Quantification of mononuclear cells in lung tissue of HLA-DP2 Tg mice treated as indicated (PBS, n = 3; BeO n = 4; BeO/LPS, n = 4). Bars for all data plots represent the mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001, Mann-Whitney U test (A) and 1-way ANOVA (B, C, E, and G). Data are representative of 2 separate experiments.