Selection and expansion of T cell from untreated patients with CLL: source of cells for immune reconstitution?
BACKGROUND
Lymphocyte-derived malignancies can be treated with combinations of drugs that efficiently eradicate normal and malignant lymphocytes. Lack of T lymphocytes after treatment of B lymphocyte CLL (B-CLL) makes the patients susceptible to serious infections and may limit the benefit of the therapy. The aim of the study was to purify and culture-expand normal T lymphocytes from B-CLL patients prior to therapy. These cells could be frozen and given to the patients in the lymphopenic period post-chemotherapy.


METHODS
T lymphocytes were isolated from the mononuclear cell apheresis products from five patients with previously untreated B-CLL. The apheresis products were red-cell depleted by density gradient centrifugation. B-lymphocyte purging was performed by incubating with MAbs to four different B-cell epitopes, followed by magnetic-bead depletion. One round of negative selection removed >90% of the B lymphocytes. The T-lymphocyte enriched cell suspension was cultured for 10/11 days in the presence of IL-2 and the anti-T cell receptor Ab OKT3. In addition, in some cultures anti-CD22 ricin immunotoxin was added.


RESULTS
T cells from CLL patients expanded 4.7-21-fold over a 10/11 days culture interval. After culture, CLL cells could no longer be identified by flow cytometric evaluation. The cultured T lymphocytes were predominantly CD8(+), and were capable of lysing autologous CLL cells through a fas-dependent mechanism.


CONCLUSIONS
Selection and expansion of T lymphocytes by this method may represent a strategy for enhancing immunity in the lymphopenic period following CLL treatment.
Husebekk
A
A
Department of Transfusion Medicine, Clinical Center, National Cancer Institute/NIH, Bethesda, MD, USA.
Fellowes
V
V
Read
E J
EJ
Williams
J
J
Petrus
M J
MJ
Gress
R E
RE
Fowler
D H
DH
D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D002857:Chromium / Q000378:metabolism; D000939:Epitopes; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000097:blood / Q000276:immunology* / Q000628:therapy*; D008297:Male; D013601:T-Lymphocytes / Q000166:cytology* / Q000502:physiology*; D013997:Time Factors
D000939:Epitopes; D002857:Chromium