Respiratory viral infection (RVI) following human lung transplantation (LTx) increases the risk for chronic rejection. We demonstrated that lung transplant recipients (LTxR) with acute and chronic rejection induce exosomes containing HLA and self-antigens (SAg), Kα1Tubulin (Kα1T) and Collagen V (Col-V). We determined whether RVI can induce exosomes containing SAg leading to immune response resulting in rejection and their immunogenicity in mice. Sera from RVI (n=35) and stable LTxR (n=32) were used for exosomes isolation and Abs to SAg. Exosomes were isolated by ultracentrifugation, validated by sucrose cushion and tested for CD-9. SAg, viral antigens for respiratory syncytial virus (RSV), corona virus (CV) and rhino virus (RV) were detected by immunoblot. Exosomes from RVI and stable LTxR were injected subcutaneously (10[micro]g/100[micro]l) into C57BL/6 mice. Sera were analyzed for Abs to SAg by ELISA. Since studies have shown that a primary insult to lung is needed for Abs to SAg to induce Obliterative Airway Disease (OAD) we administered 0.1% HCL into the native lungs on day 1. Lungs from immunized mice were analyzed for histopathology with H&E and trichrome. Sera from RVI patients contained exosomes with increased concentration of Col-V (0.73±0.09 vs 1.9±0.2, p=0.0003) and Kα1T (4.06±1.09 vs 0.83±0.31, p=0.009) compared to exosomes from stable. The sera demonstrated increased Abs to SAg (Col-V; 54.9±25.1 vs 78.3±71.1, p=0.0169; Kα1T, 43.3±27.2 vs 74.7±64.6, p=0.0145). RVI LTxR also contained viral antigens RSV (6.3±2.1vs1.2±0.3, p=0.033) CV (3.7±1.1vs 0.8±0.2, p=0.021) and RV (5.3±1.6 vs 1.1±0.1, p=0.030) compared to stable. Sera from mice immunized with RVI exosomes showed increased Abs to SAg (Col-V, 28.1±4.0 vs 45.9±6.5, p=0.04; Kα1T, 230.4±77.1 vs 604.6±140, p=0.04). Mice immunized with RVI exosomes following lung injury by HCL also showed cellular infiltration and fibrosis of the airways compared to stable exosomes injected mice. RVI following LTx induces exosomes containing SAg, viral antigens and Abs to SAg. Immunization of mice with exosomes from RVI leads to immune responses to SAg resulting in histopathology similar to OAD. Therefore, persistent exosomes originating from the transplanted lung following RVI can lead to immune responses increasing the risk for chronic rejection following LTx.

CITATION INFORMATION: Gunasekaran M., Bansal S., Sharma M., Walia R., Hachem R., Limaye A., Bremner R., Smith M., Mohanakumar T. Respiratory Viral Infections Induces Exosomes and Antibodies to Lung Self-Antigens, Kα1Tubulin and Collagen V, Following Human Lung Transplantation Am J Transplant. 2017;17 (suppl 3).

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