Description
Principle of the assay: human CD5 ELISA Kit was based on standard sandwich enzyme-linked immune-sorbent assay technology. A monoclonal antibody from mouse specific for CD5 has been precoated onto 96-well plates. Standards(NSO, R25-N371) and test samples are added to the wells, a biotinylated detection polyclonal antibody from goat specific for CD5 is added subsequently and then followed by washing with PBS or TBS buffer. Avidin-Biotin-Peroxidase Complex was added and unbound conjugates were washed away with PBS or TBS buffer. HRP substrate TMB was used to visualize HRP enzymatic reaction. TMB was catalyzed by HRP to produce a blue color product that changed into yellow after adding acidic stop solution. The density of yellow is proportional to the human CD5 amount of sample captured in plate.
Background: CD5, also known as T1 or LEU1, is a cluster of differentiation found on a subset of IgM-secreting B cells called B-1 cells, and also on T cells. It is mapped to 11q12.2. Although CD5 can be found on both T cells and B cells, T cells express higher levels of CD5 than B cells. CD5 was used as a T-cell marker until monoclonal antibodies against CD3 were developed. CD5 is upregulated on T cells upon strong activation. In the thymus, there is a correlation with CD5 expression and strength of the interaction of the T cell towards self-peptides. Nevertheless, CD5 serves to mitigate activating signals from the BCR so that the B-1 cells can only be activated by very strong stimuli (such as bacterial proteins) and not by normal tissue proteins