Pharmacological and immunological aspects of histamine release from horse leucocytes.

This study focuses on the fact that some widely recognized pharmacological agents that trigger histamine release from certain types of cells do not have the same effect on horse leucocytes. However, some substances including concanavalin A and an anti-horse IgG antiserum do induce this histamine release. The findings expand understanding and could inform further research regarding allergies in horses.

Research Context and Aims

• The research is initially set in the context of known pharmacological histamine releasing agents such as compound 48/80 and poly-L-lysine. These agents are established to trigger histamine release from particular types of cells, notably rat peritoneal mast cells and to a lesser extent, peripheral blood leucocytes.
• The aim of the study is to assess the effects of these and other agents on horse leucocytes, which have previously shown little to no histamine release when exposed to these agents.

Research Findings and Implications

• The paper reports that several recognized histamine-releasing agents have little to no effect in inducing histamine release from horse leucocytes. Specifically, the calcium ionophore A 23187 did not induce any histamine release.
• Conversely, the study found that Concanavalin A successfully induced histamine release from horse leucocytes. The paper suggests that this may be due to the quantity of IgE-like antibodies present on the cells.
• An anti-horse IgG antiserum that is thought to react with IgE light chains also triggered histamine release from horse leucocytes.
• Through inhibition studies using the antibody with isoproterenol, adrenaline, and colchicine, the investigators noticed that histamine release was inhibited in a similar way to previous studies on human leucocytes and rat mast cells.
• The study also revealed that deuterium oxide, a substance known for enhancing histamine release, boosted this release from horse leucocytes in a dose-dependent manner.
• While IgE or IgE-like immunoglobulin hasn’t been isolated in horses yet, the article mentions a reported bronchopulmonary allergy in horses that is presumed to be mediated by IgE. This implies that the study could be an important step in exploring allergies in horses further.
• The findings suggest that assessing histamine release in vitro could enable more effective comparative studies of this type of allergy.