Characterisation of equine T helper cells: demonstration of Th1- and Th2-like cells in long-term equine T-cell cultures.

The research focuses on the identification and study of two types of T helper cells (Th1 and Th2) present in horses. These cells are crucial for initiating and controlling immune reactions.

Objective of Research

• The main aim of the research was to identify and characterise CD4+T-cells in horses. These cells are of utmost importance in triggering immune responses or managing established ones.

Research Methodology

• Peripheral blood mononuclear cells from a pony immunised with ovalbumin (a protein found in egg white) were cultured in vitro (outside the body, in a controlled environment).
• This culture was done in the presence of the specific antigen (substance that triggers an immune response) and autologous antigen-presenting cells (cells from the same individual that process and present antigens for the T-cells).
• In the absence of the antigen (starvation phase), cells were maintained on recombinant equine IL-2 (a type of protein that regulates immune responses).

Observations and Findings

• After 35 days of culture, the majority of the cells were CD4+, CD8- (markers for T helper cells) and sIg- (surface Ig- indicating absence of B-cells).
• These cells showed specific growth in the presence of the antigen. This was tested on day 42 of the culture.
• Further inspection of these cells was done by in-situ hybridisation (a technique that allows observing gene expression at a specific location) to detect mRNA for IL-2 and IL-4. mRNA (messenger RNA) are molecules that carry coding information for the synthesis of proteins from the DNA.
• The presence of IL-2 and IL-4 suggested the existence of Th1- and Th2-like cells respectively. These cells are subsets of T helper cells and have distinct roles in immune response. While Th1 cells are involved in cell-mediated immunity, Th2 cells are crucial for humoral or antibody-mediated immunity.