Detection of endogenous biotin in various tissues: novel functions in the hippocampus and implications for its use in avidin-biotin technology

Abstract

Significant amounts of endogenous biotin were detected by avidin-peroxidase in fixed rat kidney, liver, and brain. The staining was indistinguishable from the true signals of immunoreactivity and could not be consistently blocked by pretreatment with avidin. The finding that certain neurons in the hippocampus contain more biotin than neurons in other areas of the brain suggests that biotin might have novel functions in the brain other than its well-known role as cofactor of carboxylases. Critical examination of published immunohistochemical localization studies on rat kidney strongly suggests that many false-positive results have been considered as true signals. Interference of endogenous biotin in any study using avidin-biotin technology must be considered if biological tissues are involved. The published data obtained by this method should therefore be reevaluated. Furthermore, appropriate controls, blockers and caution in interpreting results must be exercised, not only in immunohistochemistry but also in any applications of avidin-biotin technology.

Stromal Cell–Derived Factor-1α and CXCR4 Expression in Hemangioblastoma and Clear Cell-Renal Cell Carcinoma: von Hippel-Lindau Loss-of-Function Induces Expression of a Ligand and Its Receptor

“…Staining was also absent when both primary and secondary antibodies were omitted (data not shown). The staining for SDF-1a was in distal tubules, whereas the highest biotin concentration is in proximal tubules (29) in which staining was absent. We therefore conclude that staining of normal tubular epithelium adjacent to the CC-RCCs for SDF-1a and CXCR4 is specific and not the result of endogenous biotin activity.…”

Labeled Trichoderma reesei Cellulase as a Marker for Acanthamoeba Cyst Wall Cellulose in Infected Tissues

“…Due to the high affinity of the binding, avidin-biotin technology is widely used in histochemical procedures. However, the presence of endogenous biotin in various cells and tissues and its potential interference with the test can cause false-positive results (17). With the blocking step included in the test described here we could significantly reduce the background staining.…”

Mast cells and multiple sclerosis in females and males

“…Mast cell tryptase (Fl-275): sc 32889). One series of sections were immuneprosessed twice: first with a kit (Vector Lab., Inc. Avidin/Biotin blocking kit sp-2001) for blocking biotin before immune-labelling, since biotin has been reported to be a significant source for false positive DABstaining in several tissues [13], and thereafter immune prosessed and DAB-stained for human mast cell tryptase.…”