T lymphocytes can mediate lysis of autologous melanoma cells by multiple mechanisms: evidence with a single T cell clone.
The specificity analysis of a CD3+, WT31+, CD8+ cytotoxic T lymphocyte (CTL) clone (CTL 49), isolated from peripheral blood lymphocytes of a melanoma patient (no. 665) after mixed lymphocyte culture with an HLA-A2+ allogeneic lymphoblastoid cell line (VSKB-LCL), revealed that CTL 49 could lyse, in addition to HLA-A2+ lines, autologous HLA-A2- melanoma (Me665/2) and K562 targets. Killing of VSKB-LCL, but not of Me665/2, could be inhibited by anti-CD3 and by anti-HLA-A2 antibodies or by modulation of the CD3 complex. Cold-target competition studies showed that K562, but not VSKB-LCL, could compete with Me665/2 for lysis by CTL 49. However, unlike K562, Me665/2 could be lysed by CTL 49 in a Ca2(+)-independent fashion in 4 h and 18 h assays. CTL 49 expressed mRNA specific for tumor necrosis factor (TNF alpha) and, to a lesser extent, for lymphotoxin (TNF beta). Exposure of the clone to anti-CD3 antibodies induced the expression of interferon(IFN)-gamma-specific mRNA. Antibodies to TNF alpha, TNF beta and IFN reduced the lysis of Me665/2, but not of K562, by CTL 49 in 18-h cytotoxic assays. Antibodies to TNF alpha and to IFN gamma almost completely inhibited the lysis seen on Me665/2 (but not on K562), in 96-h assays, by supernatants isolated from VSKB-LCL- or anti-CD3-stimulated CTL 49 cells. Taken together, these data indicate that major-histocompatibility-complex-independent lysis of autologous tumor cells and of natural killer reference targets by the same alloreactive T cell clone are activities related at the level of target recognition but distinct at the level of the lytic hit. Thus, efficient lysis of autologous tumor cells results from a complex mechanism based upon direct effector-target interaction as well as on cytokine-mediated cytolytic effects.
Mazzocchi
A
A
Division of Experimental Oncology D, Istituto Nazionale Tumori, Milan, Italy.
Anichini
A
A
Castelli
C
C
Sensi
M
M
Poli
F
F
Russo
C
C
Parmiani
G
G
D002118:Calcium / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects; D002999:Clone Cells / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D016207:Cytokines / Q000494:pharmacology; D015870:Gene Expression; D006680:HLA Antigens / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D008545:Melanoma / Q000276:immunology / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000276:immunology
D016207:Cytokines; D006680:HLA Antigens; D012333:RNA, Messenger; D011948:Receptors, Antigen, T-Cell; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D002118:Calcium