Bio-Rad Affi-Gel Protein A Media - Manual (Page 4)

application has been limited because most mouse IgG
1
immunoglob-
ulins have low affinity for protein A. This results in poor IgG
1
reten-
tion on protein A-agarose columns. 1,5-7 Since most mouse IgG
monoclonal antibodies belong to the IgG
1
subclass, poor IgG
1
reten-
tion represents a significant purification problem.
Figure 1 shows the results achieved with the Affi-Gel protein A
MAPS method for the purification of several monoclonal antibod-
ies including IgG
1
, IgG
2a
, and IgG
2b
subclasses.
Fig. 1. Comparison of IgG
1
recoveries using Affi-Gel protein A MAPS
method and standard method.
Mouse ascites fluid containing equivalent amounts (5 mg) of
either mouse IgG
1
, IgG
2a
, or IgG
2b
monoclonal antibodies were
chromatographed in 1 ml columns of Affi-Gel protein A agarose.
Chromatography was performed with the Affi-Gel protein A MAPS
kit. It is evident that almost quantitative recovery was achieved in
all 3 cases in which IgG
1
-containing mouse ascites was chro-
matographed using the MAPS kit. Improved results were also
observed with IgG
2b
antibodies.
2
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