C-C motif chemokine ligand (CCL) production in equine peripheral blood mononuclear cells identified by newly generated monoclonal antibodies.

The research article discusses a study focused on the production of C-C motif chemokine ligands, also known as CCLs, in the peripheral blood mononuclear cells of horses. Through the generation of specific monoclonal antibodies, the researchers aim to improve the understanding and analysis of the production and function of chemokines in horses, with the goal of better evaluating innate immune responses in the species.

Study Methodology and Procedures

• The study involved the production of monoclonal antibodies that were specific to the equine CCL ligands. This was achieved using a technological process known as hybridoma technology.
• The specificity of the produced antibodies was then tested and confirmed through intracellular staining. This process was performed on Chinese Hamster Ovary cells, which had been transfected with vectors encoding for the four different CCL ligands being studied.
• The transfected cells were then stained with the produced CCL antibodies and analyzed using flow cytometry to ascertain the specificity of each monoclonal antibody to the respective chemokine.

Findings of the Study

• The researchers were able to detect the production of various CCL ligands in the peripheral blood mononuclear cells of horses, depending on their stimulation and/or culture condition.
• Production of CCL2 was detected in a few monocytes, specifically those with CD14 receptors, when these cells were stimulated with Phorbol Myristate Acetate (PMA) and ionomycin for two hours. CCL3 production was found in CD14 monocytes after having been cultured in medium for 4-6 hours.
• Longer stimulation (12-24h) with PMA and ionomycin resulted in production of CCL3 in lymphocytes, mainly the CD4 T cells. Interestingly, Lipopolysaccharide (LPS) stimulation appeared to decrease the percentage of CCL3-monocytes.
• CCL5 was detected in peripheral blood mononuclear cells without stimulation, in both CD4 and CD8 T cells. Notably, stimulation with PMA and ionomycin or cultures longer than 6 hours seemed to reduce the percentage of CCL5 cells.
• CCL11 was produced by CD4 T cells following stimulation with PMA and ionomycin for 4-24 hours. Equal production of CCL2, CCL5, and CCL11 was observed when PBMCs were stimulated with LPS in comparison to when they were cultured in medium alone.

Research Implications and Utility of the Monoclonal Antibodies

• The study indicated that the monoclonal antibodies generated for equine CCL chemokines could be useful in quantitatively analysing chemokine production both intracellularly and in a soluble state, utilising flow cytometry and ELISA techniques respectively.
• The antibodies can significantly contribute to the study of the immune responses in horses, enabling researchers to better understand and evaluate the role and behaviour of chemokines in equine innate immune response.