Flow-cytometric method for the quantitation of the Fc function of intravenous immunoglobulin preparations.
OBJECTIVE
We have developed and optimised a new flow-cytometric method for the measurement of the Fc function of intravenous immunoglobulin (IVIg) preparations, which is important in predicting the effector function of immunoglobulin (Ig) in such preparations.


METHODS
Ig was bound to a monocytic cell line, THP-1 with Fc gammaRI and Fc gammaRII cell surface receptors, and the bound Ig detected by FITC-conjugated F(ab)2 fragment of rabbit anti-human IgG.


RESULTS
Validation studies showed that Ig bound to the cell line through the Fc portion. The method detected alterations in Fc function caused by reduction with dithiothreitol or by storage. The method was reproducible (CV<11%) and a limited comparison study showed that it correlated with the European Pharmacopoeia reference method.


CONCLUSIONS
This technically simple method is suitable for the quantitation of the Fc function of Ig preparations.
Ramasamy
I
I
Molecular Biology Section, Therapeutic Goods Administration Laboratories, Woden, Australia. indra.ramasamy@health.gov.au
Tran
E
E
Charnock
A
A
Farrugia
A
A
D000911:Antibodies, Monoclonal / Q000378:metabolism; D000937:Antigen-Antibody Reactions; D002460:Cell Line / Q000276:immunology; D003634:DDT / Q000378:metabolism / Q000494:pharmacology; D019281:Dimerization; D004355:Drug Stability; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007141:Immunoglobulin Fc Fragments / Q000502:physiology*; D007074:Immunoglobulin G / Q000187:drug effects / Q000378:metabolism; D016756:Immunoglobulins, Intravenous / Q000276:immunology*; D009000:Monocytes / Q000276:immunology; D010084:Oxidation-Reduction; D011961:Receptors, Fc / Q000378:metabolism; D017452:Receptors, IgG / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013696:Temperature
D000911:Antibodies, Monoclonal; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D016756:Immunoglobulins, Intravenous; D011961:Receptors, Fc; D017452:Receptors, IgG; D011993:Recombinant Fusion Proteins; D003634:DDT