Effects of adenosine and deoxyadenosine on PHA-stimulation of lymphocytes of man, horse and pig.

This study examines the effects of adenosine and deoxyadenosine on the functionality of lymphocytes stimulated by phytohemagglutinin (PHA) in humans, horses, and pigs.

Adenosine and Deoxyadenosine Impact on Lymphocyte Functionality

• Adenosine and deoxyadenosine were found to inhibit thymidine and uridine incorporation of PHA-stimulated lymphocytes in humans and horses at certain concentrations. These substances were shown to only be inhibitory at concentrations over 50 and 10 microM, and 100 microM, respectively.
• In pigs, it was observed that adenosine, deoxyadenosine, inosine and hypoxanthine increased thymidine and uridine incorporation issues in lymphocytes by 5-7 times when present within the concentration range of 25-100 microM.
• Leucine incorporation of PHA-stimulated lymphocytes was affected by adenosine and deoxyadenosine in a similar fashion, albeit to a lesser degree.

Effects of Cultivation Times and Additional Compounds

• Shorter cultivation periods were associated with a more noticeable impact of adenosine and deoxyadenosine on lymphocytes.
• A compound named EHNA was found to amplify the effects of adenosine and deoxyadenosine on human and equine lymphocytes. In humans, a combination of EHNA and deoxyadenosine resulted in greater inhibition than a combination of EHNA and adenosine. For pig lymphocytes, only the combination of deoxyadenosine and EHNA was inhibitory.

Interaction with Homocysteine and Impact on PRPP Concentrations

• The presence of an additional substance, homocysteine, enhanced the inhibition of thymidine incorporation by a combination of adenosine and deoxyadenosine in horses, although this effect was not replicated when adenosine or deoxyadenosine were acting alone.
• The study also found that adenosine was able to suppress the PHA-stimulated elevation of PRPP concentrations in lymphocytes. In pigs, PRPP levels remained consistent with zero-hour levels, while in horses, levels decreased to below that marker.

Metabolism Differences and their Effects

• The variable effects of adenosine and deoxyadenosine on lymphocytes in humans, horses, and pigs, according to the study, can be partially ascribed to differences in the metabolisation of these two substances in the species under observation.