Selenium status and phytohemagglutinin-stimulated T lymphocytes from beef calves

Area of Science:

• Veterinary Immunology
• Animal Nutrition
• Cellular Immunology

Background:

• Selenium (Se) is a vital trace element influencing immune function.
• Assessing T lymphocyte blastogenesis is crucial for evaluating cellular immunity in cattle.
• Geographical areas with low soil selenium can lead to marginal deficiencies in livestock.

Purpose of the Study:

• To investigate the impact of selenium (Se) supplementation on in vitro phytohemagglutinin (PHA)-stimulated T lymphocyte blastogenesis in calves.
• To determine the effects of calf age on T lymphocyte responsiveness.

Main Methods:

• Crossbred calves (n=8) were divided into control and Se-treated groups.
• Selenium was administered via subcutaneous injections.
• Peripheral blood lymphocytes were cultured with PHA and [(3)H]-thymidine to measure thymidine incorporation.
• Stimulation index (SI) was calculated to assess lymphocyte blastogenesis.

Main Results:

• Se-treated calves achieved adequate selenium status, confirmed by plasma Se and glutathione peroxidase levels.
• Selenium treatment did not significantly influence T lymphocyte blastogenesis (SI values).
• Lymphocyte stimulation index (SI) was significantly affected by age, with higher responses observed in younger calves (45 days) compared to older calves (124 and 270 days).

Conclusions:

• Selenium supplementation did not alter T lymphocyte responsiveness to PHA stimulation in beef calves.
• Age significantly impacts T lymphocyte blastogenesis, with younger calves exhibiting greater responsiveness.
• Beef calves in selenium-deficient regions may maintain normal T lymphocyte function despite marginal selenium status.