Phagocytosis of opsonized fluorescent microspheres by equine polymorphonuclear leukocytes.

This research study focuses on creating a standard method to measure the process of phagocytosis – or cellular ingestion – of marked minute particles by a type of white blood cell called polymorphonuclear leukocytes (PMN) in horses. The authors also devise an evaluation system that aids in understanding the potential influence of medications on this cell function in various settings.

Method of Research

• The authors began by isolating equine PMNs from blood samples using a buffy coat method and a procedure called hypotonic lysis to eliminate the remaining red blood cells.
• The PMNs were then tested for their ability to ingest, or ‘phagocytose,’ fluorescent latex microspheres that had been treated to make them more attractive to the immune cells – a process known as opsonization.
• The researchers monitored and measured this process using flow cytometry, a technique that counts and sorts microscopic particles suspended in a fluid, like cells.

Key Findings

• An effective way to distinguish between particles that have been ingested and those merely attached to the PMNs was devised through the use of a substance known as cytochalasin D. This allows for more precise measurement of the process of phagocytosis.
• The researchers detailed the rates of phagocytosis under different experimental conditions, helping further understand the dynamics of this process in the body.
• A test was developed to assess the phagocytic capacity of PMNs, providing a useful tool to measure how various drugs might influence this cellular process, both in a laboratory setting (in vitro) and within a living organism (in vivo).

Significance of the Study

This research proposes a new standard for more accurate measurement and understanding of phagocytosis by PMNs. It provides a means for researchers to differentiate ingested from merely bound particles, offering a more accurate, reproducible model for studying this process. Furthermore, the development of an assay to measure potential drug influences on phagocytosis might be instrumental in drug development and testing, with potential applications in equine veterinary medicine, immunological research, and beyond.