Comparison of systemic and local respiratory tract cellular immunity in the neonatal foal.

This research investigates the immune responses in newborn horses, particularly focusing on the role of different types of white blood cells in the blood and lungs. The scientists carried out cellular function tests on these cells before and after the foals ingested colostrum, which is the first form of milk produced immediately following the birth. These tests showed improved function in blood cells after colostrum intake. Additionally, they compared these cells to those in the lungs and found fewer lung cells capable of engulfing and destroying pathogens.

Cellular Function Tests on Foals’ Blood Neutrophils

• Using in-vitro cellular function tests on blood neutrophils from 10 Thoroughbred and 2 Pony foals, researchers were able to assess the functioning of these cells.
• Tests included measurements of chemotaxis (cell movement), chemiluminescence (light emission as a result of chemical reactions), phagocytosis (cell’s ability to engulf and destroy microbes), and intracellular killing (cell’s ability to kill bacteria within its own structure).

Improvement in Blood Neutrophil Functions Post Colostrum Ingestion

• Comparing the functional abilities of blood neutrophils before and after the foals’ ingestion of colostrum (the first breastmilk), the researchers found improved chemotaxis and chemiluminescence.
• Colostrum is particularly rich in nutrients and antibodies, which could explain the observed improvement in these functions, as the newborn foals’ immunity is effectively ‘boosted’.

Bronchopulmonary Lavage and Analysis of Pulmonary Alveolar Macrophages

• Bronchopulmonary lavage, a procedure to wash out the lung’s airways using a saline solution, was performed on 9 Thoroughbred and 2 Pony foals that were 36 hours old. This procedure didn’t require sedation or anaesthesia.
• The procedure allowed researchers to recover and analyse the cells present within the lungs’ airways, with the pulmonary alveolar macrophages being the most common type found.

Comparison Between Blood Neutrophils and Pulmonary Alveolar Macrophages

• Comparisons between blood neutrophils and pulmonary alveolar macrophages in the same animal revealed fewer pulmonary alveolar macrophages were capable of phagocytosis.
• No substantial evidence of intracellular killing by the pulmonary alveolar macrophages was found. This implies that these lung cells’ primary function might not be pathogen destruction, or they may need additional stimuli or conditions for effective pathogen engulfment and destruction.