title: Minor Antigen Vaccine-Sensitized DLI: In Vitro Responses Do Not Predict In Vivo Effects.
abstract: We reported on a pilot study of minor histocompatibility antigen vaccination using constructs expressing male-specific gene disparities of selected mouse CDNA on Y and sex determining region Y in the canine model. We performed reduced-intensity hematopoietic cell transplantation with female donors and male recipients, producing stable mixed donor-recipient hematopoietic chimeras. We then performed a vaccine series in three female transplant donors followed by donor lymphocyte infusion (DLI) into their respective mixed chimeras. One mixed chimera experienced a significant shift in the percentage of donor chimerism, but no response occurred in the other 2 recipients. We then hypothesized that inadequate donor sensitization was responsible for these results.
  
  
  METHODS
  To test this hypothesis, we added 4 monthly booster vaccinations to 2 of the original hematopoietic cell transplantation donors, including the donor that drove the partial response, followed by a second DLI.
  
  
  RESULTS
  Strong T cell responses were shown by ELISpot and confirmed by intracellular cytokine staining in both donors. A second DLI resulted in a further increase in donor chimerism in the same mixed chimera that experienced the previous increase, but no change in donor chimerism was again seen in the other recipient. Evaluation of RNA expression of the target antigens demonstrated that conversion occurred in the recipient that expressed both selected mouse CDNA on Y and sex determining region Y.
  
  
  CONCLUSIONS
  T cell responses against Y chromosome-encoded disparities were not necessarily sufficient to drive in vivo female antimale responses. Other factors including the presence of specific haplotypes or the heterogeneous expression of the target antigen may affect T cell responses against minor histocompatibility antigens. These results warrant future vaccine studies in a larger transplant cohort using epigenetic modulation of the recipient to promote target gene expression.
authors.affiliation: Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA.; Department of Medicine, University of Washington, Seattle, WA.
authors.forename: Steven Lawrence
authors.initials: SL
authors.lastname: Rosinski
authors.affiliation: Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA.
authors.forename: Brad
authors.initials: B
authors.lastname: Stone
authors.affiliation: Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA.; Department of Medicine, University of Washington, Seattle, WA.
authors.forename: Scott S
authors.initials: SS
authors.lastname: Graves
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA.; Washington National Primate Research Center, University of Washington, Seattle, WA.
authors.forename: Deborah H
authors.initials: DH
authors.lastname: Fuller
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA.
authors.forename: James T
authors.initials: JT
authors.lastname: Fuller
authors.affiliation: Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA.; Department of Medicine, University of Washington, Seattle, WA.
authors.forename: Rainer
authors.initials: R
authors.lastname: Storb