TY - JOUR
T1 - The effect of serum immunoglobulin concentration on immune complex detection by polyethylene glycol
AU - Soltis, Ronald D
AU - Hasz, D. E.
N1 - Funding Information:
This study was supported by National Institutes of Health Grant AM26086.
PY - 1983/2/25
Y1 - 1983/2/25
N2 - The addition of 4% polyethylene glycol (PEG) to serum and quantitation of immunoglobulins in the dissolved precipitate has been advocated as a simple, reliable method for detecting circulating immune complexes. Because pathological sera, which often yield positive results in this assay, may contain increased concentrations of immunoglobulins compared to normal control sera, we have determined the relationship between total serum immunoglobulin concentration and the quantity of immunoglobulins precipitated by 4% PEG. When IgG was added to normal serum, the quantity and percentage of IgG in the precipitate was directly proportional to total serum IgG concentration. This concentration-dependent precipitation appeared to be unrelated to the presence of aggregates in the IgG preparation, the serum concentration of albumin, or interactions with serum complement. With normal serum, concentrated to yield a wide range of endogenous immunoglobulin concentrations, the percentage of IgG, IgM and IgA in the PEG precipitates was likewise directly proportional to the total serum concentration of these immunoglobulins. In view of these findings, this method is likely to give false-positive results in pathological sera containing increased immunoglobulin concentrations and is probably invalid as a means for detecting circulating immune complexes. However, with a final concentration of 2% PEG, successful discrimination between aggregated immunoglobulin and monomeric IgG may be achieved.
AB - The addition of 4% polyethylene glycol (PEG) to serum and quantitation of immunoglobulins in the dissolved precipitate has been advocated as a simple, reliable method for detecting circulating immune complexes. Because pathological sera, which often yield positive results in this assay, may contain increased concentrations of immunoglobulins compared to normal control sera, we have determined the relationship between total serum immunoglobulin concentration and the quantity of immunoglobulins precipitated by 4% PEG. When IgG was added to normal serum, the quantity and percentage of IgG in the precipitate was directly proportional to total serum IgG concentration. This concentration-dependent precipitation appeared to be unrelated to the presence of aggregates in the IgG preparation, the serum concentration of albumin, or interactions with serum complement. With normal serum, concentrated to yield a wide range of endogenous immunoglobulin concentrations, the percentage of IgG, IgM and IgA in the PEG precipitates was likewise directly proportional to the total serum concentration of these immunoglobulins. In view of these findings, this method is likely to give false-positive results in pathological sera containing increased immunoglobulin concentrations and is probably invalid as a means for detecting circulating immune complexes. However, with a final concentration of 2% PEG, successful discrimination between aggregated immunoglobulin and monomeric IgG may be achieved.
KW - immune complex assay
KW - polyethylene glycol
UR - http://www.scopus.com/inward/record.url?scp=0020631135&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0020631135&partnerID=8YFLogxK
U2 - 10.1016/0022-1759(83)90087-X
DO - 10.1016/0022-1759(83)90087-X
M3 - Article
C2 - 6827107
AN - SCOPUS:0020631135
SN - 0022-1759
VL - 57
SP - 275
EP - 282
JO - Journal of Immunological Methods
JF - Journal of Immunological Methods
IS - 1-3
ER -