Application of flow cytometry in veterinary medicine

What is flow cytometry?
Use of flow cytometry in veterinary medicine
Limitations and future prospects
List of references
Further reading


The last few decades have completely changed the veterinary sciences; for example, the life expectancy of both cats and dogs has increased to a higher level than ever before. Veterinary science not only improves the health and welfare of animals, but can also be critical to human health through the monitoring and control of zoonotic diseases. One of the methods that is gaining popularity is flow cytometry, especially for evaluating the immunological status and development of animals.

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What is flow cytometry?

Flow cytometry is a widely used method for assessing quantitative and qualitative aspects of cells, especially in hematology and immunology. Flow cytometry uses lasers to generate signals that are detected and converted into data that provides insight into the cells being analyzed. Flow cytometry uses expensive equipment and requires highly qualified specialists.

Over the past 30 years, flow cytometry has made significant advances that have made it more widely used and easier to navigate. It has also become a more reliable and efficient tool, making it a more attractive method of biochemical analysis. This has led to its increasing use in veterinary medicine.

Use of flow cytometry in veterinary medicine

Flow cytometry is used in many areas of veterinary medicine; immunology, oncology, diagnosis of autoimmune diseases, quantitative determination of reticulocytes, medical monitoring, rabies.

Flow cytometry plays a crucial role in the evaluation of immune function, especially in dogs. Flow cytometry revealed a subset of suppressive CD4+ T cells. Some animals that expressed higher levels of suppressive T cells were less likely to develop autoimmune disorders. This discovery led to the conclusion that these cells are relevant to the mechanism of self-defense, as they regulate and limit the immune system, preventing it from over-activating and attacking its own cells. This better understanding of the role of immune cells is vital to the treatment of various conditions.

One of the new applications of flow cytometry is the pharmacodynamic monitoring of drugs. In some life-threatening conditions, getting the right treatment sooner greatly increases the chances of survival, so a reliable drug monitoring technique is essential.

Image credit: Babul Hosen/Shutterstock.com

Image credit: Babul Hosen/Shutterstock.com

Cyclosporine, a powerful drug that suppresses the production of T cells, is used in veterinary medicine to treat inflammatory and autoimmune diseases. Cyclosporine interferes with the production of immune cytokines such as IFN-Y and IL2, weakening the immune response. Pharmacodynamic monitoring involves observing the effect of a drug and ensuring that it is within therapeutic limits.

One research group developed an assay for cyclosporine to measure its effects on canine tissue and observed two points in these assays; at low doses, the drug inhibited IFN-Y, whereas at higher doses it inhibited both IFN-Y and IL2. In this analysis, flow cytometry was able to verify the efficacy of the drug and identify new markers.

The application of flow cytometry is not limited to treatment, but can also be used to diagnose diseases such as parasitaemia (parasitic infection of the blood) in dogs. There are currently two main methods used to diagnose this; review of blood smear and PCR (polymerase chain reaction).

Using blood smears can be tricky because many parasites will be needed for a positive test result; leading to many false negative results. As a method, PCR is very sensitive; even a few parasitized erythrocytes would lead to a false positive result. Flow cytometry is an intermediate link between these methods and allows obtaining a more reliable result.

A new approach to the detection of intracellular antigens of the rabies virus involves the use of flow cytometry. One advantage of using flow cytometry in this field would be to reduce the time required to confirm viral infection. The technique could therefore be crucial to industry currently trying to produce rabies vaccines or antiviral drugs.

Image credit: hedgehog94/Shutterstock.com

Image credit: hedgehog94/Shutterstock.com

Flow cytometry has a promising future in oncology. Acute leukemia in dogs is rarely cured and has a poor prognosis; it is also associated with poor differentiation of cell lines. Classification of acute leukemia along different lineages may improve prognosis. Traditional methods currently used to characterize cell lines are subjective in interpretation and difficult to quantify; therefore, flow cytometry would allow more developments in this field. Flow cytometry can evaluate numerous characteristics of a large number of cells using relatively objective criteria.

Limitations and future prospects

Although flow cytometry has a promising future in many areas of veterinary science, it has its own set of challenges that need work. Some of the limitations include the high cost of the tools and the need for highly skilled personnel. Single-cell suspensions are also required for flow cytometry, as aggregates will give false results. However, looking at the limitations, the uses and value of flow cytometry still remain. Some of the information obtained by flow cytometry has been used to improve and refine a more quantitatively reliable reverse transcriptase PCR assay; it demonstrates the wide range of uses of flow cytometry and its importance in future scientific research.

List of references

  • J., Thomason and Archer, Todd and Makin, Andrew and Stokes, John and Pinchuk, Lesya. (2014). Application of flow cytometry in veterinary research and clinical practice of small animals. Journal of Veterinary Medicine and Research. 1. 1-9.
  • Reggeti, F., & Bienzle, D. (2011). Flow cytometry in veterinary oncology. Veterinary pathology, 48 (1), 223–235. https://doi.org/10.1177/0300985810379435
  • Molla, D., Z. Tekle, A. Ayisheshim, D. Kebede, A. Wondimu and WM Ahmed, 2019. Flow cytometry and its diagnostic applications in animal health: a review. Global Vet., 21: 1-7. DOI: 10.5829/idosi.gv.2019.01.07

Further reading

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