Characterization of equine natural killer and IL-2 stimulated lymphokine activated killer cell populations.

The research investigates the identification and characterisation of Natural Killer (NK) cells and lymphokine activated killer (LAK) cells in horses. The study found that equine NK cells can be identified using a molecule NK-5C6 and differentiated from IL-2 stimulated LAK cells through their unique cytotoxic response to specific target cell lines.

Research Methodology

• The research studied Natural Killer (NK) cells in horses. NK cells, which are part of the innate immune system and have been intensively studied in humans and rodents, are less understood in other species.
• One of the challenges of studying these cells is the lack of specific cell markers. However, in this study, a molecule called mAb NK-5C6 was used. This molecule is thought to recognize an evolutionarily conserved molecule on NK cells and reacts with cells from several species.
• Two-color flow cytometry analysis was used to identify the NK-5C6 positive cell population. This method found that these cells were CD3-CD4- and CD8-, but positive for Major Histocompatibility Complex (MHC) class I and Lymphocyte function-associated antigen 1 (LFA-1) expression.

Research Findings

• The research found that the NK-5C6 molecule labelled approximately 10% of peripheral blood lymphocytes (PBL) in horses.
• When CD3+ T cells were removed, the percentage of NK-5C6 positive cells in PBL increased, and this population demonstrated a specific cytotoxic response against a major histocompatibility complex (MHC) deficient NK target cell line.
• Using this method, the researchers were able to identify and characterize an equine NK cell population that has endogenous lytic activity and a phenotype similar to that of human and mouse NK cells.

Additional Research Findings

• The researchers also found that stimulating peripheral blood mononuclear cells (PBMC) with IL-2 promoted the development of lymphokine-activated killer (LAK) cells.
• These LAK cells were predominantly CD3+ T cells, showed intracellular perforin expression, and effectively lysed both K-562 and EqT8888 target cells.
• These findings indicate that equine NK cells can be identified by the NK-5C6 mAb and distinguished from IL-2 stimulated LAK cells by their unique cytotoxic response to specific target cell lines.