Antigen-specific free immunoglobulin light-chain antibodies: could it be a new diagnostic marker for patients with allergy?
OBJECTIVE
Human free immunoglobulin light chains (FLCs) have long been considered as nonmeaningful spillover remnants from the process of immunoglobulin production; however, recent findings suggest that the antibody activity of FLCs may be involved in the pathology of allergic responses. We therefore assessed the antigen-binding ability of FLCs to evaluate their usefulness as diagnostic markers for patients with allergy.


METHODS
FLCs were separated from the serum samples of patients seropositive against cedar pollen and mice immunized with bovine serum albumin and 1-fluoro-2,4-dinitrobenzene by ultrafiltration and protein G absorption. A sensitive immunoassay confirmed the absence of any IgG in the separated FLC fractions from the human serum samples.


RESULTS
Solid-phase immunoassay for cedar pollen showed that none of the human serum samples possessed any antibody activity against the antigen after the removal of whole immunoglobulins. Furthermore, while the immunized mice also showed high antibody titers against the antigens, but the serum specimens showed no residual antibody activity against the antigens after the FLCs were separated from the whole immunoglobulins.


CONCLUSIONS
The results of the present study suggested that the FLC fractions may possess little or no antigen-binding activity, and that therefore, they may not serve as useful diagnostic markers in patients with allergy.
Nakano
Takanari
T
Department of Biochemistry, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan. tnakano@saitama-med.ac.jp <tnakano@saitama-med.ac.jp>
Takahashi
Hidenori
H
Miyazaki
Shuichi
S
Kawai
Shin-ichiro
S
Shinozaki
Rina
R
Komoda
Tsugikazu
T
Nagata
Atsuo
A
D000818:Animals; D018926:Anti-Allergic Agents / Q000378:metabolism; D000906:Antibodies; D000937:Antigen-Antibody Reactions; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000097:blood*; D007147:Immunoglobulin Light Chains / Q000032:analysis* / Q000097:blood*; D051379:Mice; D008807:Mice, Inbred BALB C
D018926:Anti-Allergic Agents; D000906:Antibodies; D007147:Immunoglobulin Light Chains