Equine trophoblast as an immunological target.

This research investigates whether certain cells in horses, specifically equine chorionic girdle cells, are susceptible to attack by a type of cell in the horse’s immune system, the CD8+ cytotoxic T lymphocytes. The results indicate that the equine chorionic girdle cells are indeed targeted by CD8+ T lymphocytes and it was further revealed that in in vitro conditions these cells do not possess any protective mechanisms against activated maternal T cells.

Target Cell Analysis

• The study involved a kind of experiment known as a cytotoxic T-lymphocyte assay.
• This was used to determine whether equine chorionic girdle cells in horses could be attacked or ‘lysed’ (broken down) by CD8+ cytotoxic T cells – T cells are an integral part of the immune system response to disease.
• The activity of these cytotoxic T-lymphocytes was tested both against fresh and cultured trophoblast targets using peripheral blood lymphocytes (a type of white blood cell) from nonpregnant mares.

Control Comparisons

• The researchers also looked at the lysis of allogeneic (horse) and xenogeneic (donkey) lymphocyte targets as a control for trophoblast lysis, to compare whether the trophoblast cells were more or less susceptible than these other cell types.
• The exact specificity of the cytotoxic T-lymphocytes’ actions was determined using panels of cells specifically typed for their major histocompatibility complex (MHC), a crucial part of the immune reaction to disease.

Results & Their Implication

• The study showed that MHC class I antigens (proteins that trigger immune response) on equine chorionic girdle cells are functional and can be targets for the CD8+ allospecific cytotoxic T lymphocytes.
• This suggests that these cells may play a part in the immune reaction in the horse.
• Moreover, the findings strongly suggest that these MHC class I positive chorionic girdle cells do not possess any protective mechanisms to prevent them from being attacked or lysed (broken down) by activated maternal T cells, at least in the in vitro (laboratory) conditions used.