APC-conjugated anti-pig primary antibodies are directly labeled immunoreagents that combine a porcine antigen-specific immunoglobulin with the far-red-emitting phycobiliprotein allophycocyanin (APC). Unlike APC-conjugated anti-pig secondary antibodies, which recognize pig immunoglobulins, these primary conjugates bind their target antigen directly, enabling single-step staining. APC is excited by the 633–640 nm red laser line and emits at approximately 660 nm, a spectral window well separated from the 488 nm-excited FITC and PE channels. This makes APC conjugates valuable for multicolor flow cytometry panels in swine immunology, where the reagent landscape remains less developed than in human or mouse systems.

Applications

APC-conjugated anti-pig primary antibodies are employed primarily in flow cytometry for immunophenotyping of porcine leukocyte subsets. Anti-pig CD3ε-APC (clone PPT3) is widely used at dilutions around 1:500 to identify T lymphocytes in blood and tissue suspensions, and has been applied in studies of African swine fever virus pathogenesis. Anti-pig γδ T cell receptor-APC (clone MAC320) recognizes the SWC6 heterodimer on CD2− null T cells, a population abundant in young pigs, and does not react with pig erythrocytes, monocytes, or granulocytes. Anti-pig CD335-APC (clone VIV-KM1) was the first monoclonal developed to specifically identify porcine NKp46/NCR1 and is validated for flow cytometry and immunofluorescence. Anti-pig CD31-APC recognizes PECAM-1 on endothelial cells, and anti-pig CD90-APC (clone 5E10) is reactive with pig, horse, human, and non-human primate CD90. Beyond flow cytometry, these conjugates support immunofluorescence microscopy and, for some clones, Western blotting.