Optimized monoclonal antibody panel for accurate immunohistochemical detection of haematopoietic cell populations in animal species.

BACKGROUND: Immunohistochemistry (IHC) has emerged as an essential tool in characterizing neoplastic diseases, playing a crucial role in both human and veterinary medicine. Despite the increased demand for specific diagnoses in veterinary oncology, the full potential of IHC has been hampered by the reduced number of specific cross-reactive antibodies recognising their antigens in diverse animal species. This study addresses this limitation by testing the cross-reactivity of a panel of 69 antibodies, including one in-house generated monoclonal antibody, using IHC on routinely fixed formalin-fixed paraffin-embedded tissues of lymph node, spleen or bursa of Fabricius samples from domestic (n = 13) and exotic/wild (n = 28) animal species as well as normal human lymph node. RESULTS: We successfully identified a panel of 16 monoclonal or multiclonal antibodies targeting lymphoid (CD3, CD4, CD8, FOXP3, PD-1, TOX2, CD19, CD20, CD21, CD79a, CD79b, BCL-2, BCL-6, IRF-4, PAX5) and myeloid (CD163) antigens that are cross reactive across species. This comprehensive panel enables the precise detection of the most important subpopulations of haematopoietic cells, including T and B cells, macrophages and dendritic cells. CONCLUSIONS: The results improve the availability of antibodies for immunohistochemical studies in veterinary clinical practice and research. The cross-reactive antibody panel identified here is a versatile tool for further studies in immunophenotyping immune cell populations in diverse animal species. It represents a significant advance toward improved diagnostic accuracy in veterinary medicine, facilitating the study of these cell populations under normal and pathological conditions.