Tumor antigen-specific T-cell expansion is greatly facilitated by in vivo priming.
OBJECTIVE
Adoptive T-cell therapy is a promising strategy for the treatment of patients with established tumors but is often limited to specific cancers where tumor-infiltrating lymphocytes, the source of T cells for ex vivo culture, can be obtained. In this study, we evaluated the feasibility of expanding HER-2/neu-specific T cells derived from peripheral blood ex vivo following in vivo priming with a HER-2/neu peptide vaccine.


METHODS
Peripheral blood mononuclear cells from cytomegalovirus (CMV)-seronegative and CMV-seropositive donors as well as HER-2/neu-positive cancer patients who had or had not been vaccinated with a HER-2/neu peptide-based vaccine was used as a source of T lymphocytes. Antigen-specific T-cell lines were generated by in vitro stimulation with antigen followed by nonspecific expansion on CD3/CD28 beads. The ability to expand antigen-specific T cells was assessed using IFN-gamma and granzyme B enzyme-linked immunosorbent spot. The phenotype of the resultant T-cell lines was evaluated by flow cytometry, including the presence of FOXP3-expressing CD4(+) T cells.


RESULTS
The frequencies of CMV-specific T cells generated from CMV(+) donors were >11-fold higher than the frequencies from CMV(-) donors (P = 0.001), with 22-fold increase of total number of CD3(+) T cells. The frequencies of HER-2/neu-specific T cells generated from the primed patients were >25-fold higher than the frequencies from unvaccinated patients (P = 0.006), with an average of a 19-fold increase of total number of CD3(+) T cells. Using peripheral blood as the source of T cells did not result in concurrent expansion of FOXP3(+)CD4(+) regulatory T cells despite the use of interleukin-2 in in vitro culture. Both CD4(+) and CD8(+) HER-2/neu-specific T cells could be expanded. The extent of ex vivo expansion correlated with the magnitude of immunity achieved during immunization (P = 0.008).


CONCLUSIONS
Tumor-specific T cells can be efficiently expanded from the peripheral blood ex vivo following in vivo priming with a vaccine. This approach provides an effective method to generate tumor-specific polyclonal T cells for therapeutic use that could be applied to cancer patients with any tumor type.
Dang
Yushe
Y
Tumor Vaccine Group, Center for Translational Medicine in Women's Health, University of Washington, Seattle, WA 98109, USA. ydang@u.washington.edu
Knutson
Keith L
KL
Goodell
Vivian
V
dela Rosa
Corazon
C
Salazar
Lupe G
LG
Higgins
Doreen
D
Childs
Jennifer
J
Disis
Mary L
ML
D000951:Antigens, Neoplasm / Q000276:immunology*; D001943:Breast Neoplasms / Q000097:blood / Q000276:immunology / Q000628:therapy / Q000821:virology; D019496:Cancer Vaccines / Q000276:immunology* / Q000627:therapeutic use; D049109:Cell Proliferation; D002478:Cells, Cultured; D003587:Cytomegalovirus / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007156:Immunologic Memory; D016219:Immunotherapy, Adoptive / Q000379:methods; D008213:Lymphocyte Activation / Q000276:immunology*; D010051:Ovarian Neoplasms / Q000097:blood / Q000276:immunology / Q000628:therapy / Q000821:virology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology* / Q000637:transplantation* / Q000821:virology
D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D018984:Epitopes, T-Lymphocyte; D018719:Erb-b2 Receptor Tyrosine Kinases