CDR3 spectratyping identifies clonal expansion within T-cell subpopulations that demonstrate therapeutic antitumor activity.
BACKGROUND
Antigen-specific T cells undergoing clonal expansion share common rearrangements of the variable complementary determining region 3 (CDR3) of the T-cell receptor (TCR), which can be identified using polymerase chain reaction-based V beta (VB) spectratyping. The purpose of this study was to determine whether CDR3 spectratyping identifies clonal expansion within tumor-draining lymph node (TDLN) subpopulations with antitumor therapeutic activity.


METHODS
Recently sensitized T cells from 4T1 murine mammary carcinoma TDLN were fractionated based on CD62L (L-selectin) surface expression before RNA isolation and culture. L-selectinlow and L-selectinhigh TDLN were analyzed for T-cell receptor usage by immunophenotyping and CDR3 spectratyping, and then culture activated with anti-CD3/IL-2 to assess therapeutic efficacy after adoptive transfer.


RESULTS
Adoptive transfer experiments confirmed that mice treated with culture-activated L-selectinlow TDLN cells exhibited delayed subcutaneous tumor growth and prolonged survival as compared to control or L-selectinhigh-treated mice (P < .01). CDR3 spectratyping demonstrated oligoclonal skewing of the CDR3 regions within several VB families including VB3, VB5.2, and VB17 in L-selectinlow but not in L-selectinhigh TDLN. Although fluorescence-activated cell sorter analysis demonstrated the highest percentage of cells expressing VB13 usage in both populations, CDR3 spectratyping did not identify the presence of clonal expansion.


CONCLUSIONS
These data suggest that CDR3 spectratyping may be useful in identifying T cells undergoing clonal expansion that demonstrate antitumor therapeutic activity.
Department of General Surgery and the Section of Experimental Hematology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Julian A
JA
Kim
Poornima
P
Rao
Hallie
H
Graor
Kevin
K
Rothchild
Christine
C
O'keefe
Jaroslaw P
JP
Maciejewski
D000818:Animals; D002999:Clone Cells / Q000276:immunology; D022801:Complementarity Determining Regions; D005260:Female; D016219:Immunotherapy, Adoptive; D019041:L-Selectin / Q000502:physiology; D008198:Lymph Nodes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009374:Neoplasms, Experimental / Q000276:immunology / Q000628:therapy*; D016176:T-Lymphocyte Subsets / Q000276:immunology*
D022801:Complementarity Determining Regions; D019041:L-Selectin