Successful oral administration of suppressor t cell exosomes strongly inhibiting immune inflammation in the skin

New data from the Phil Askenase group at Yale University School of Medicine describes successful oral administration of suppressor T cell-derived exosomes strongly inhibiting immune inflammation in the skin. The results were largely contributed by visiting Professors Krzysztof Bryniarski  and Katarzyna Nazimek  from the Jagellonian College of Medicine in Kracow, Poland. The group studied skin allergic CD4^pos T cell and macrophage orchestrated effector inflammation in the ear skin of mice that was strongly inhibited by oral administration of antigen-specific suppressor CD8^pos T cell-derived exosomes delivering miRNA-150.  Quantitated skin responses were measured kinetically over five days were to the common milk protein casein. The antigen specificity was due to anti-casein antibody light chains coating the exosomes. This was demonstrated by flow cytometry, that also showed that the suppressive exosomes also expressed CD9, CD63 and CD81.

The functioning exosomes were definitively identified by specific affinity column fractionation with beads linked to casein antigen and separately to CD9.  They were recovered and tested for function in vivo. The suppressor exosomes were administered orally in a single physiological dose at the peak of the skin immune inflammatory response.  These  miRNA-150^pos exosomes produced very strong inhibition of the T cell dependent skin inflammation for at least the subsequent four days.  In fact, the oral route produced grater suppression then also examined and more commonly used intraperitoneal, even intravenous and intradermal routes, that also were also administered as a single dose systemically.

This system has many advantages to truly test the xeno miRNA dietary delivery hypothesis concerning activity of food exosome miRNA in ingesting mammalian subjects. For considering the validity of oral miRNA treatment, this skin immune system administers only exosomes, that only work if antigen-specific and delivering miRNA-150 to antigen presenting cells that regulate the effector CD4^pos T cells mediating the immune inflammation. This Askenase laboratory system is measured quantitatively and kinetically, entirely by in vivo function; allowing both dose response and time course determinations, with antibody and miRNA markers to be followed, and functioning to likely make epigenetic alterations affecting skin inflammation, that can be measured in a variety of ways.

Suppression of delayed-type hypersensitivity (DTH) to soluble casein (Cas) antigen is induced by intravenous (iv) injection of Cas-coupled syngeneic red blood cells and by CD8+ suppressor T (Ts) cell-derived extracellular vesicles (EVs) administered via different routes.

(A) Mice had been administered iv with Cas-coupled syngeneic red blood cells, which was followed by intradermal (id) immunization with a saline solution of soluble Cas antigen (100 µg per mouse) 5 days before challenging by id administration of the same Cas solution (5 µg per earlobe). Subsequent ear swelling response was measured daily up to 120 h after challenge and expressed as delta ± SEM [units (U) × 10⁻² mm] (n = 5, N = 2). (B) Mice had been id immunized with a saline solution of soluble Cas antigen (100 µg per mouse) 5 days before challenging by id administration of the same Cas solution (5 µg per earlobe). After measurement of 24 h ear swelling, Ts cell EVs were administered intraperitoneally (ip), id, iv, or per os, and subsequent ear swelling response was measured daily up to 120 h after challenge and expressed as delta ± SEM [units (U) × 10⁻² mm] (n = 5, N = 2). * p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001.

These findings are very important since in general they resemble the clinical situation of treating a patient with a pre-existing and ongoing immune-mediated response. Further, such successful and powerful suppressive exosome administration by the oral route, if translated to the clinical situation, represents a low impact and high effect treatment modality that obviously would be appealing to patients; especially children. Possible application to clinical conditions involving protein Ag-specific Delayed-Type Hypersensitivity-like systems include: asthma, autoimmunity like multiple sclerosis, transplantation and cancer immunity. Such protein Ag-specific universal therapeutic exosomes would be an entirely new, novel, unique and unprecedented dual Ag-specific and gene-specific therapeutic approach for therapies, since none currently exist for chosen Ag-specific targeting and delivery of selected therapeutic miRNA or RNAi.