Effect of ascorbic acid in vitro on lymphocyte reactivity to mitogens

Area of Science:

• Immunology
• Cell Biology
• Biochemistry

Background:

• Ascorbic acid (vitamin C) is crucial for immune function.
• Its role in lymphocyte proliferation requires further elucidation, especially concerning its oxidized forms.

Purpose of the Study:

• To investigate the in vitro effects of ascorbic acid and dehydroascorbic acid on human lymphocyte proliferation.
• To determine the impact of these compounds on mitogen-stimulated immune responses.

Main Methods:

• Human lymphocytes were stimulated with phytohemagglutinin (PHA) and concanavalin A (Con A).
• Tritiated thymidine ([3H]TdR) incorporation was measured to assess proliferation.
• Cell viability, RNA, and protein synthesis were also evaluated.

Main Results:

• Physiologic and high concentrations of ascorbic acid and dehydroascorbic acid inhibited [3H]TdR incorporation in a dose-dependent manner.
• Inhibition occurred even when ascorbic acid was added late in the culture period.
• Non-cytotoxic concentrations of ascorbic acid and dehydroascorbic acid impaired lymphocyte activation.

Conclusions:

• Ascorbic acid and dehydroascorbic acid negatively regulate lymphocyte proliferation.
• These vitamins interfere with early metabolic events in mitogen-induced lymphocyte activation.
• The findings suggest a complex role for vitamin C in modulating immune cell responses.