Preferential clonogenic deficit of CD8-positive T-lymphocytes infiltrating human solid tumors.
The vast majority of tumor infiltrating lymphocytes (TIL) are either CD4+ or CD8+ T-lymphocytes. In order to examine directly the functional capabilities of the individual CD4+ and CD8+ TIL subsets we performed cell sorting of double immunofluorescence-labeled TIL recovered from 15 biopsies by enzyme digestion. These CD4+ and CD8+ TIL subsets were compared with similar subsets of T-lymphocytes from peripheral blood of normal subjects. Both CD4+ and CD8+ TIL showed a reduced clonogenicity as assessed quantitatively by limiting dilution analysis in a microculture system which allows every normal T-lymphocyte to undergo clonal expansion. The reduced clonogenic potential was unequally distributed among the CD4+ and CD8+ subsets with the CD8+ TIL showing a significant reduction of the frequency of proliferating T-lymphocyte precursors compared to the CD4+ TIL (with a median of 1/50 proliferating T-lymphocytes in CD8+ TIL versus a median of 1/11 in CD4+ TIL). The reduced response of CD8+ TIL was not caused by suppressor cells, lack of surface expression of CD2 and CD3 antigens nor of the alpha, beta T-cell receptor, nor by an accumulation of CD8+ cells of large granular lymphocyte morphology. Using low density cultures, the highly purified CD4+ and CD8+ TIL were stimulated either via the T-cell receptor or the CD2-mediated antigen-independent pathway of activation. Whereas CD8+ TIL did not respond to either stimulus the CD4+ TIL showed evidence of responder and nonresponder groups. In addition, we show that the deficient response obtained by triggering CD4+ TIL via the TCR can be restored by activation of the antigen-independent pathway. Finally, a total of 94 clones from four different TIL samples were obtained by limiting dilution and examined for their respective helper and cytolytic capabilities: 57% of the CD4+ TIL clones were able to produce interleukin 2 and 93% of the CD8+ TIL clones demonstrated cytolytic activity mediated by the T-cell receptor complex, indicating that the functional potential of proliferating TIL is intact.
Miescher
S
S
Ludwig Institute for Cancer Research, Lausanne Branch, Epalinges, Switzerland.
Stoeck
M
M
Qiao
L
L
Barras
C
C
Barrelet
L
L
von Fliedner
V
V
D000368:Aged; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D002455:Cell Division; D003602:Cytotoxicity, Immunologic; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000276:immunology*; D010641:Phenotype; D013601:T-Lymphocytes / Q000032:analysis*
D000945:Antigens, Differentiation, T-Lymphocyte; D007376:Interleukin-2