Autologous Bone Marrow Transplantation - Blog Science Connections

Purging Methods in Burkitt's Lymphoma 361
10 7 cells/ml in Hanks' medium) were incubated 20 minutes with monoclonal
antibodies and then twice with complement, with one wash between the two
complement treatments. Complement was used at one-third final dilution.
DNase 1 (sterile nonpyrogenic pancreatic DNase from Sigma, St. Louis, MO)
(5 Cl/ml) was added to each complement treatment. All media were buffered
with HEPES (Tebu).
Residual malignant cells were quantified by a liquid cell culture assay (4;
see also the above-named chapter by I. Philip et al. in this volume). After
treatment, samples initially contaminated with 1 % BL cells are grown in a liquid
culture system, and the percentage of growing BL cells at day 10 compared to a
calibration curve enables us to quantify the number of residual BL cells after
treatment. If no BL cells are detectable at day 10, samples are kept for 2 more
weeks in culture before we conclude that all BL cell growth has been inhibited, a
finding usually correlated to the complete elimination of these cells in this
assay.
Mean results are then expressed in decimal logarithms of the initial ratio of
malignant and normal cells divided by the final ratio after the purging
procedure. In individual experiments, results are expressed as percentages of
growing BL cells in the culture at day 10.
RESULTS AND DISCUSSION
Results shown in Table 1 prompt three comments. First, whatever
monoclonal antibody is used, the BL 9 3
cell line is partially resistant to the
complement. Second, contrary to general opinion, SB 4
monoclonal antibody
alone is as efficient as the two cocktails of monoclonal antibodies. RFB 7
shows a
Table 1. Efficiency of the Complement Lysis Procedure
Mean Cell Kill (log)
Cell Lines
(no. of experiments)
RFB 7
SB 4
RFAL 3
Y29/55 RFB 7
RFB 7
+ SB 4
+ SB 4
+ Y29/55
IARC BL 9 9
(n = 8)
EBV (+) (8,22)
Caucasian
5 >5 4.5 3 >5 5
IARC BL 9 3
(n = 5)
EBV (-) (8,14)
Caucasian
2.5 1.5 2 2 3 2.5
IARC BL 2
(n = 5)
EBV (-) (8,22)
Caucasian
4 >5 5 5 >5 5
Abbreviation: EBV, Epstein-Barr virus.