Autologous Bone Marrow Transplantation - Blog Science Connections

446 Immune-magnetic Purging ofBurkitt's Cells
we observed a partial failure of the procedure, having only a 2- to 3-log
malignant cell elimination. These three failures could be owed to the use of a
cocktail of three MAbs, two of them being irrelevant. Indeed, as shown in Table
2, in three of four experiments B-, alone was more efficient than the cocktail of
three MAbs, suggesting that Y29/55 and J 5
can inhibit, probably by competition,
the attachment of the beads to the cell through the linkage of antimouse IgG.
As shown in Table 3, in preliminary experiments in which samples were
Table 2. Percentage of Burkitt's Lymphoma Cells at Day 10 of Culture
Cell Treated Samples 3 Calibration Curve 6
Line B, Cocktail 10-5 10-6
BL 9 9 80 100 100 10
BL 2 0 60 100 80
80 0 100 100
B
L
93 0 45 60 50
Note: A comparison of the percentage of malignant cells at day 10 of culture in the
treated samples, to that indicated by the calibration curve permits measurement of
residual Burkitfs lymphoma cells after the purging. For example, for cell line BL 93, B,
enables a full elimination of Burkitfs lymphoma cells, whereas in the calibration curve at
roe, malignant cells remain after the cocktail treatment (a 4-log elimination).
"One percent contamination before treatment.
"Untreated samples contaminated with Burkitfs lymphoma cells.
Table 3. Comparative Efficiency of IgM and IgG Monoclonal Antibodies
in Direct and Indirect Methods
Indirect Method Direct Method Indirect Method
Cell Experiments (log) (log) (log)
Line (n) B, RFB 7 SB 4 RFB 7
SB„
BL 9 9* 3 2 1.5 1
BL 9 3
a
2 1.5 1.5 1.3 —
BL 9 9
or
BL 9 3
6
2 1.6 0.65 0.15 — —
BL93 2 1.75 1.25 0.9 2 1.5
Note: Evaluation was by the Hoechst staining method (samples were contaminated
with 10% Burkitfs lymphoma cells).
ln the first two series of experiments,
a
monoclonal antibody coupling.
beads were used within 3 days of the
"In this experiment, beads were used within 18 days of the monoclonal antibody
coupling.