Atto-conjugated anti-horse primary antibodies are fluorescent immunoreagents designed for the high-sensitivity detection of equine antigens in advanced fluorescence-based applications. Produced by immunizing host species such as goat or rabbit with purified horse immunoglobulins, these antibodies are affinity-purified and covalently conjugated to Atto fluorophores—a family of synthetic dyes recognized for their exceptional brightness, narrow emission spectra, and superior photostability. The fluorophores are typically attached through NHS ester or maleimide chemistries to lysine or cysteine residues, using controlled labeling ratios that preserve antigen-binding affinity while maximizing fluorescence intensity.
Atto Fluorophore Properties
The Atto dye family covers a broad spectral range from 390 nm (UV/violet) to 700 nm (near-infrared), with commonly available variants for horse-specific detection including Atto 390, Atto 488, Atto 565, Atto 633, Atto 655, Atto 680, and Atto 700. Atto 488 is widely used as an alternative to fluorescein due to its enhanced brightness and photostability. Atto 594 offers excellent water solubility and maintains a high quantum yield across a broad pH range (2–10). Atto 647N delivers exceptional fluorescence intensity together with outstanding pH stability and photostability, making it a reliable alternative to Cy®5 and Alexa Fluor® 647. To minimize non-specific binding, these antibodies are commonly pre-adsorbed against immunoglobulins from related species, effectively reducing cross-reactivity.
Applications
Atto-conjugated anti-horse primary antibodies are widely used in fluorescence-based immunoassays. In immunofluorescence and confocal microscopy, their superior photostability enables prolonged image acquisition and supports super-resolution techniques such as stimulated emission depletion (STED) microscopy, achieving nanometric resolutions of approximately 30–50 nm. In flow cytometry, their high fluorescence intensity facilitates the detection of low-abundance equine antigens in complex multicolor panels. These conjugates are also suitable for western blotting, ELISA (frequently validated at dilutions greater than 1:10,000), high-content screening, and multiplex bead-based assays. Optimal antibody dilutions should be determined empirically for each experimental application. These products are intended for research use only and are not approved for diagnostic procedures.
