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Antiviral Cytotixic T Lymphocytes Can be Rapidly Generated Against an Extended Spectrum of Viruses
Saturday, March 5, 2016: 2:45 PM
Theatre, Room 411 (Convention Center)
Michael Keller, MD, , ,
Rationale: Adoptive immunotherapy using virus-specific cytotoxic T-lymphocytes (VST) has been successful in restoring antiviral immunity in patients with primary immunodeficiency.  We hypothesized that ex vivo expanded VST generated using a rapid GMP compliant protocol will be (i) polyclonal and polyfunctional and (ii) elicit broad activity against multiple viral antigens in a single culture.

Methods: VST were cultured by stimulating peripheral blood mononuclear cells from 5 healthy donors with overlapping peptide pools encompassing 17 epitopes from 8 viruses (CMV, EBV, adenovirus, BK virus, human herpesvirus 6B, RSV, influenza (H3N2), and varicella), followed by 10-12 days of culture with cytokines.   VST were tested via flow cytometry, IFN-g ELISpot against viral epitopes, and for non-alloreactivity via 51Cr cytotoxicity assays using HLA-mismatched PHA blasts. 

Results: VST predominantly expressed CD3+ (mean 92%, range 88-95%) and CD4+ (mean 66%) or CD8+ (mean 29%), with few B-cells or natural killer cells (<1%). Central memory T-cells (CD3+/CD45RA-/CCR7+) were present in all VST lines (mean 14.6%, range 9-19%). Viral specificity was seen against a median of 7 viruses (range 3-8), with T-cells responding to a median of 12 epitopes tested on Inf-g elispot (range 5-17).  VST demonstrated no killing (<5% specific lysis) of mismatched PHA blasts in cytotoxicity assays.

Conclusions: VST can be rapidly expanded with specificity against 8 viruses, with CD4, CD8, and central memory populations suggesting polyclonality. VST are non- alloreactive in vitro, and may be beneficial for prevention and treatment of a multitude of viral infections in patients with primary immunodeficiency.