PerCP-conjugated anti-horse primary antibodies are red-fluorescent immunoreagents designed for multicolor flow cytometry using 488 nm laser excitation. Produced by immunizing hosts such as goat, rabbit, or mouse with purified horse immunoglobulins, the antibodies are affinity-purified and conjugated to Peridinin Chlorophyll Protein Complex (PerCP), a 35 kDa photosynthetic pigment-protein complex isolated from dinoflagellates (primarily Glenodinium species). PerCP exhibits unique spectral properties with excitation maxima at 488 nm and emission maxima at approximately 675 nm, providing a large Stokes shift of approximately 187 nm. The complex consists of peridinin (a carotenoid) and chlorophyll a molecules non-covalently associated with protein subunits, enabling efficient energy transfer from peridinin to chlorophyll a. With a molar extinction coefficient of approximately 2.3 × 10⁵ M⁻¹cm⁻¹ and quantum yield of 0.85, PerCP offers exceptional brightness, approximately 2–4 times brighter than PE and 5–10 times brighter than FITC under optimal conditions. The far-red emission at 675 nm minimizes spectral overlap with FITC (525 nm), PE (578 nm), and PE/Atto 594 (617 nm), making PerCP an excellent choice for multicolor panels. Available specificities include anti-IgG (H+L), anti-IgG (Fc), anti-IgG1, anti-IgG2, and anti-IgM reagents. Products are typically cross-adsorbed against immunoglobulins from mouse, rat, rabbit, and bovine to ensure high specificity in multi-species samples.

Applications

PerCP conjugates are extensively employed in flow cytometry and FACS for immunophenotyping equine peripheral blood mononuclear cells (PBMCs), detecting surface markers such as CD4, CD8, CD14, CD21, and MHC class II (ELA). The far-red emission (675 nm) with minimal spectral overlap facilitates simultaneous detection with FITC (green), PE (orange), and APC (far-red) in 4- to 6-color panels, making PerCP particularly valuable for high-parameter immunology studies. However, PerCP exhibits moderate photosensitivity and is susceptible to spectral changes when exposed to fixatives such as paraformaldehyde; long-term fixation (> 24 hours) should be avoided. These conjugates are also applicable in immunofluorescence microscopy, where far-red emission provides good contrast against background autofluorescence. Additional applications include high-content screening, cell proliferation assays, and multiplex bead-based assays.

Typical working dilutions for flow cytometry range from 1:20 to 1:200. These reagents should be stored at 4°C, protected from light, and should not be frozen. Intended for research use only and not for diagnostic procedures.