Diverse expansion potential and heterogeneous avidity in tumor-associated antigen-specific T lymphocytes from primary melanoma patients.
While tumor-associated antigen (TAA)-specific CD8(+) T lymphocytes have been detected in metastatic melanoma patients, immune response in early disease phases has not yet been carefully evaluated. We looked for circulating cytotoxic T lymphocytes (CTL) directed against Melan-A / MART1, tyrosinase, gp100 and MAGE-3 antigens in patients with a diagnosis of primary cutaneous melanoma by using fluorescent HLA-A2 tetramers. In five out of six cases high numbers of CD8(+)/tetramer(+) cells could be detected by flow cytometry, and in four patients lymphocyte populations specific for two different melanoma antigens (Melan-A/MART1 and tyrosinase) were contemporaneously present. The TAA-specific cells could represent as much as 1/220 T lymphocytes in the circulating CD8(+) population. When tetramers were used to monitor the in vitro expansion of TAA-specific CTL precursors upon antigen-specific stimulation, a diverse expansion potential was evidenced in CTL from the different donors and, more strikingly, in CTL specific for the different TAA. Melan-A/MART1-specific CTL clones derived from two patients exhibited a broad range of avidity. Only the highest avidity clones, representing about 50 % of the cases analyzed, were tumor specific. By correlating tetramer staining with clone avidity, we found that tetramer fluorescence intensity could represent a good indicator of TCR affinity, but not of overall clone avidity.
Palermo
B
B
Experimental Immunology IRCCS Maugeri Foundation, Pavia, Italy.
Campanelli
R
R
Mantovani
S
S
Lantelme
E
E
Manganoni
A M
AM
Carella
G
G
Da Prada
G
G
della Cuna
G R
GR
Romagne
F
F
Gauthier
L
L
Necker
A
A
Giachino
C
C
D000328:Adult; D000951:Antigens, Neoplasm / Q000276:immunology*; D005260:Female; D005453:Fluorescence; D015789:HLA-A2 Antigen / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D058965:MART-1 Antigen; D008297:Male; D008545:Melanoma / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000276:immunology; D008875:Middle Aged; D014442:Monophenol Monooxygenase / Q000276:immunology; D009363:Neoplasm Proteins / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D058951:gp100 Melanoma Antigen
D000951:Antigens, Neoplasm; D015789:HLA-A2 Antigen; C072013:MAGEA3 protein, human; D058965:MART-1 Antigen; C548667:MLANA protein, human; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C548637:PMEL protein, human; D011948:Receptors, Antigen, T-Cell; D058951:gp100 Melanoma Antigen; D014442:Monophenol Monooxygenase