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Human - Anti-Collagen Type I & II Antibody Assay

Chondrex provides human IgA and IgG antibody assay kits (can be used for monkey sera) to determine the diversity of human antibodies using various species of type I and type II collagen coated wells in addition to uncoated wells for use as a blank. These kits employ effective blocking agents to minimize non-specific reactions caused by serum components. Generally, it is impossible to accurately determine antibodies in human sera by ELISA and RIA using BSA and BSA-Tween as blocking agents.

Human/Monkey Anti-Type I Collagen IgA Antibody Assay Kit

Collagen Coated Wells Chromagen Catalog # Price (USD)
Bovine I OPD 1042 394.00
Bovine I TMB 1042T 394.00
Chick I OPD 1041 394.00
Chick I TMB 1041T 394.00
Human I OPD 1045 429.00
Human I TMB 1045T 429.00
Porcine I OPD 1043 394.00
Porcine I TMB 1043T 394.00

Human/Monkey Anti-Type I Collagen IgG Antibody Assay Kit

Collagen Coated Wells Chromagen Catalog # Price (USD)
Bovine I OPD 1032 394.00
Bovine I TMB 1032T 394.00
Chick I OPD 1031 394.00
Chick I TMB 1031T 394.00
Human I OPD 1035 429.00
Human I TMB 1035T 429.00
Porcine I OPD 1033 394.00
Porcine I TMB 1033T 394.00

Human/Monkey Anti-Type II Collagen IgA Antibody Assay Kit

Collagen Coated Wells Chromagen Catalog # Price (USD)
Bovine II OPD 2062 386.00
Bovine II TMB 2062T 386.00
Chick II OPD 2061 386.00
Chick II TMB 2061T 386.00
Human II OPD 2065 420.00
Human II TMB 2065T 420.00
Porcine II OPD 2063 386.00
Porcine II TMB 2063T 386.00

Human/Monkey Anti-Type II Collagen IgG Antibody Assay Kit

Collagen Coated Wells Chromagen Catalog # Price (USD)
Bovine II OPD 2052 386.00
Bovine II TMB 2052T 386.00
Chick II OPD 2051 386.00
Chick II TMB 2051T 386.00
Human II OPD 2055 420.00
Human II TMB 2055T 420.00
Porcine II OPD 2053 386.00
Porcine II TMB 2053T 386.00

Non-Specific Reactions in ELISA and RIA for Assaying Human Serum Antibodies

Human sera, especially from patients with autoimmune diseases, contain high levels ofimmunoreactive components, which create extremely high non-specific reactions in ELISA and RIA. These types of non-specific reactions are caused by the hydrophobic binding of immunoglobulins in sample specimens onto plastic surfaces, and cannot be blocked by ordinary blocking agents such as bovine serum albumin (BSA) and Tween 20 (Figure 1). Importantly, these false positive reactions caused by the serum sample itself have not been well understood, and are falsely considered a real antibody-antigen reaction in many cases, even now.

Figure 1 – Non-specific reactions caused by a hydrophobic binding of immunoglobun components in human sera onto plastic surfaces.

Note the OD values in antigen non-coated wells are almost equal to the OD values in human type I (HI) and type II collagen (HII)-coated wells (A). Goat serum components effectively block the hydrophobic binding of human immunoglobulins onto the plastic surfaces (B)

In order to obtain a real value of antigen-antibody reaction, it is critical

1) to choose proper blocking agents which effectively block these kinds of non-specific reactions,

2) to determine a unique non-specific background value of individual samples using antigen-non-coated wells, and

3) to subtract the background value from the value determined in antigen-coated wells.

Our ELISA kits contain enough reagents to run two plates on two separate occasions (see assay procedure) and may be used for monkey sera as well as human sera. Customized kits to measure antibody levels to various species of type I and type II collagen can be custom ordered.

Diversity of Anti-Collagen Antibodies in Human Sera

In general, antibodies to collagen in human sera are highly specific to heterologous collagen such as bovine or chick type I and/or type II collagen, and cross-react to other species and types of collagen including autologous collagen, regardless of the disease even in normal healthy controls. To determine human serum antibodies with significant diversity in antigen specificity, Chondrex provides ELISA plates (wells) coated with various species of type I and type II collagen, in addition to uncoated wells for use as a blank.

IgA antibodies to type II collagen are often associated with IgG antibodies in human sera. Importantly, IgA and IgG antibodies in individual sera share identical collagen types and species specificity, indicating that IgA and IgG antibodies were elicited by stimulation with the same collagen. Therefore, it is highly likely that heterologous collagen in the diet may play a primary role in anti-collagen antibody production, regardless of the disease. However, this does not indicate that type II collagen in the diet is the only source of antigen capable of eliciting anti-type II collagen antibodies. This is because, type I collagen also found abundantly in the diet shares amino acid sequences with type II collagen by more than 80%. In fact, the antibodies in human sera often cross-react to both type I and type II collagen.