Monocyte subsets across veterinary species

Javier Domínguez

Loems Ziegler-Heitbrock

2,*

*Correspondence to: Loems Ziegler-Heitbrock, Independent researcher, Monocytomics Research, Herrsching 82211, Germany. E-mail: LZH@monocyte.eu

Myeloid Cells. 2026;1:202601. 10.70401/mc.2026.0004

Received: null , Accepted: May 18, 2026Published: May 18, 2026

This manuscript is made available in its unedited form to allow early access to the reported findings. Further editing will be completed before final publication. As such, the content may include errors, and standard legal disclaimers are applicable.

Abstract

Monocytes consist of several subsets, which differ in their phenotype and functional capacity. This heterogeneity was first shown in man, and later evidenced in other species. Here, we review the current knowledge on the phenotype and functionality of monocyte populations in species of veterinary interest, in comparison to man. The increasing availability of reagents for leukocyte phenotypic analyses, along with the growing application of -omic technologies, are enabling a better characterization of these subsets, and facilitate comparisons across species. The review demonstrates that classical, intermediate, and non-classical monocytes can be defined in pig, cattle, sheep, camel, buffalo, horse, and dog. However, more phenotypic, functional, and transcriptomic studies are needed in some species to establish an accurate correspondence. A better understanding of shared and species-specific features of these monocyte subsets will pave the way for translational research on strategies selectively targeting these cells to treat different pathological conditions, including infectious, inflammatory, and malignant diseases.

Keywords

Monocyte subsets, veterinary species, phenotype, surface receptors, transcriptomics

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