Date: Sunday, April 30, 2017
Session Time: 4:30pm-6:00pm
Presentation Time: 4:42pm-4:54pm
Background: Exosomes isolated from acute and chronic rejections in lung transplant recipients (LTxR) demonstrated surface expression of mismatched donor human leukocyte antigen and lung associated self-antigens (SAgs) Kα1Tubulin (Kα1T) and Collagen-V (Col-V). To determine the immunogenicity of circulating exosomes, immunization of mice were carried out using exosomes isolated from LTxR with rejection or stable and resulting immune responses and their specificities were analyzed.
Methods: Exosomes were isolated using sera from rejecting bronchiolitis obliterans syndrome (BOS) and stable LTxR using ultracentrifugation method. Isolated exosomes were validated for exosome specific markers, Annexin-V and CD-63. Lung associated SAgs, Kα1T and Col-V, and co-stimulatory molecules (CD-80, CD-86) were detected by immunoblot. Serum derived exosomes from BOS (pooled N=10) and stable LTxR (pooled N=10) were used for immunization (subcutaneous with freund's incomplete adjuvant) (days 1, 13 and 20) of C57BL/6 (N=5). Sera was collected on days 10, 20 and 30 and analyzed for antibodies (Abs) to Kα1T and Col-V by ELISA. The frequency of IL17, IFN-γ and IL-10 producing cells in the spleen against SAgs were enumerated by ELISPOT.
Results: Annexin-V and CD-63 (exosome specific markers) were demonstrable on exosomes isolated from both BOS and stable LTxR. However, only exosomes isolated from BOS patients, but not stable LTxR, demonstrated expression of lung SAgs, Kα1T and Col-V. Immunization of mice with exosomes isolated from BOS patients, but not stable, developed Abs to lung SAgs (p<0.05). The animals immunized with exosomes from BOS also demonstrated increased frequency of IL17 (Kα1T, p=0.014; Col-V, 0.013) and IFN-γ (Kα1T, p=0.012; Col-V, 0.042) and reduced frequency of IL-10 producing cells (Kα1T, p=0.017; Col-V, 0.016).
Conclusion: Circulating exosomes isolated from human LTxR undergoing rejection can induce both humoral and cellular immune responses to lung SAgs. Therefore, exosomes may play an important role in augmentation and spreading of immune responses to donor allo- and SAgs leading to chronic rejection following human LTx.
CITATION INFORMATION: Gunasekaran M, Sharma M, Bansal S, Biswas Roy S, Walia R, Bremner R, Smith M, Mohanakumar T. Circulating Exosomes Isolated from Human Lung Transplant Recipients with Rejection Are Immunogenic and Induce Antibodies to Lung Associated Self-Antigens, Kα1 Tubulin and Collagen-V. Am J Transplant. 2017;17 (suppl 3).
To cite this abstract in AMA style:Gunasekaran M, Sharma M, Bansal S, Roy SBiswas, Walia R, Bremner R, Smith M, Mohanakumar T. Circulating Exosomes Isolated from Human Lung Transplant Recipients with Rejection Are Immunogenic and Induce Antibodies to Lung Associated Self-Antigens, Kα1 Tubulin and Collagen-V. [abstract]. Am J Transplant. 2017; 17 (suppl 3). https://atcmeetingabstracts.com/abstract/circulating-exosomes-isolated-from-human-lung-transplant-recipients-with-rejection-are-immunogenic-and-induce-antibodies-to-lung-associated-self-antigens-k1-tubulin-and-collagen-v/. Accessed October 24, 2020.
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