Ficolins are a family of pattern recognition molecules containing both a collagen-like domain and a fibrinogen-like domain that are capable of activating the complement system, through association with MASPs, on the surface of microorganisms. In human, three Ficolins are known: Ficolin-1 (M-ficolin), Ficolin-2 (L-ficolin), and Ficolin-3 (H-ficolin). Ficolin-1, is mainly expressed by monocytes, granulocytes and lung cells and is present locally in areas of inflammation. However, it was recently also found in serum suggesting that Ficolin-1 also has a role in systemic immunity like Ficolin-2 and Ficolin-3. Functional analysis of Ficolin-1 has demonstrated that it binds specifically to capsular polysaccharides of some microorganisms. Furthermore, it was shown that Ficolin-1 facilitates the uptake of E. coli by a leukemic monocyte lymphoma cell line, suggesting that it functions as a phagocytic receptor on the surface of circulating monocytes. Low cord blood concentration of Ficolin-1 has been associated with higher necrotizing enterocolitis-associated fatality in premature infants and polymorphisms in the Ficolin-1 gene are associated with the development of rheumatoid arthritis and susceptibility to leprosy.
The human Ficolin-1 ELISA kit is to be used for the in vitro quantitative determination of human Ficolin-1 in serum and plasma samples.
The human Ficolin-1 ELISA is a ready-to-use solid-phase enzyme-linked immunosorbent assay based on the sandwich principle with a working time of 3½ hours. The efficient format of a plate with twelve disposable 8-well strips allows free choice of batch size for the assay. Samples and standards are incubated in microtiter wells coated with antibodies recognizing human Ficolin-1. Biotinylated tracer antibody will bind to the captured human M-ficolin. Streptavidin-peroxidase conjugate will bind to the biotinylated tracer antibody. Streptavidin-peroxidase conjugate will react with the substrate, tetramethylbenzidine (TMB). The enzyme reaction is stopped by the addition of oxalic acid. The absorbance at 450 nm is measured with a spectrophotometer. A standard curve is obtained by plotting the absorbance (linear) versus the corresponding concentrations of the human Ficolin-1 standards (log).
The human Ficolin-1 concentration of samples, which are run concurrently with the standards, can be determined from the standard curve.
The linearity of the assay was determined by serially diluting plasma and serum samples containing human Ficolin-1. The diluted samples were measured in the assay.
Normal human blood samples (plasma) containing baseline levels of human Ficolin-1, were spiked with human Ficolin-1, in concentrations of 2 and 0.2µg/ml. Samples with and without human Ficolin-1, were incubated for 1 hour at 37°C. Samples were measured using the ELISA. Recovery values for human Ficolin-1, ranged between 93.9% and 97.4%.