Detection of circulating tumor lysate-reactive CD4+ T cells in melanoma patients.
OBJECTIVE
We wanted to study whether an allogeneic melanoma lysate would be a feasible stimulatory antigen source for detection of a peripheral CD4+ T-cell immune response in patients with medically untreated malignant melanoma. The lysate was produced from a melanoma cell line (FM3.29) which expresses high amounts of melanoma antigens.


METHODS
Fresh peripheral blood was incubated with and without lysate for 6 h in the presence of anti-CD28/anti-CD49d MoAb (for costimulation). After flow cytometric estimation of the frequency of CD69+/IFN-gamma+ cells in the CD4+ population, the response to lysate was calculated as the difference between the number of activated IFN-gamma-producing CD4+ cells in the lysate-stimulated and the nonstimulated sample.


RESULTS
An immune response to lysate was observed in blood samples from 11 of 15 patients (73%) with metastatic melanoma. A weak response was found in 1 of 4 patients radically operated for localized disease, whereas no responders were seen among 7 healthy donors. The fraction of circulating lysate-activated T cells ranged from 0.0037% to 0.080% of the CD4+ population. A negative result of the assay was found occasionally, especially in donors with high background levels of spontaneous IFN-gamma production, indicating an inhibitory effect of the lysate.


CONCLUSIONS
This method for detection of a peripheral T-cell immune response in melanoma patients has several advantages for clinical use. The tumor lysate preparations may contain large numbers of stimulating antigens (known, as well as unknown) and are easily prepared and handled. Potentially, the assay might be useful as a diagnostic tool, a marker of residual or recurrent disease, a prognostic factor, or a predictor or monitor of the effect of antineoplastic therapy including immune-modulating therapy.
Ladekarl
Morten
M
Department of Oncology, Aarhus University Hospital, DK-8000 Aarhus, Denmark. ladekarl@privat.dk
Agger
Ralf
R
Fleischer
Charlotte C
CC
Hokland
Marianne
M
Hulgaard
Egil F
EF
Kirkin
Alexei
A
von der Maase
Hans
H
Petersen
Mikkel S
MS
Rytter
Carsten
C
Zeuthen
Jesper
J
Gundersen
Hans Jørgen G
HJ
D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D000951:Antigens, Neoplasm / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D016022:Case-Control Studies; D003937:Diagnosis, Differential; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D037181:Lectins, C-Type; D008297:Male; D008545:Melanoma / Q000097:blood* / Q000276:immunology* / Q000556:secondary; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000473:pathology; D011379:Prognosis; D012878:Skin Neoplasms / Q000097:blood / Q000276:immunology / Q000556:secondary; D000099192:CD69 Antigens
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D000951:Antigens, Neoplasm; D007371:Interferon-gamma; D037181:Lectins, C-Type; D000099192:CD69 Antigens