Beryllium-specific CD4+ T cells induced by chemokine neoantigens perpetuate inflammation
Michael T. Falta, … , Clemencia Pinilla, Andrew P. Fontenot
Michael T. Falta, … , Clemencia Pinilla, Andrew P. Fontenot
Published February 25, 2021
Citation Information: J Clin Invest. 2021;131(9):e144864. https://doi.org/10.1172/JCI144864.
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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 7

HLA-DP2 transgenic mice and 8845-c3 TCR retrogenic HLA-DP2 mice replicate features of CBD.

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HLA-DP2 transgenic mice and 8845-c3 TCR retrogenic HLA-DP2 mice replicat...
(A) Flow cytometric density plots illustrating representative HLA-DP2–CCL4/Be (left), HLA-DP2–CCL3/Be (middle), and cotetramer staining (right) of HLA-DP2 transgenic C57BL/6 mouse BAL cells treated with BeO. (B) CCL4 and CCL3 chemokines present in the BAL fluid of BeO-treated C57BL/6 mice. BAL fluid from control (PBS: CCL4, n = 4; CCL3, n = 12) and treated (BeO: CCL4, n = 7; CCL3 n = 12) mice was assessed by ELISA. (C and D) Amino acid differences (red) between orthologous human and murine Be-dependent CCL4 and CCL3 epitopes (C) and dose-response curves of hybridoma 8845-c3 (D) comparing its activity to the human and murine peptides in the presence of BeSO4. (E) Representative CD4 staining of lungs from BeO-treated control DV-13 TCR (left panels) and Be-specific 8845-c3 TCR (right panels) retrogenic RAG–/– B6 mice showing CD4 T cell infiltrates. (F) Quantification of CD4+ T cells in lung tissue of BeO-treated DV-13 (n = 6) and 8845-c3 (n = 14) retrogenic mice. (G and H) Summary of IL-2– (G) and IFN-γ–secreting (H) T cells in spleen of PBS-exposed HLA-DP2 Tg mice (IL-2, n = 7; IFN-γ, n = 7) and BeO-exposed HLA-DP2 Tg (IL-2, n = 7; IFN-γ, n = 7) and 8845-c3 TCR retrogenic is shown (IL-2, n = 10; IFN-γ, n = 14). ELISPOT data are expressed as the mean ± SEM spot-forming units (SFUs) per 1 × 106 cells. (I) Total protein (left), albumin (middle), and podoplanin (T1a, right) measured by ELISA from BAL fluid of HLA-DP2 Tg C57BL/6 mice treated with PBS (n = 3) and BeO (n = 11) and BeO-treated 8845-c3 TCR retrogenic mice (n = 8). Statistical significance was determined using a Mann-Whitney U test (B and F) and 1-way ANOVA (G–I). Bars for all data plots represent mean values ± SEM. *P < 0.05; ** P < 0.01; *** P < 0.001; **** P < 0.0001, determined by 1-way ANOVA. Data are pooled from separate experiments.