Erythrocyte rosette formation of equine peripheral blood lymphocytes.

This research article is about the characterization of the rosette formation of equine peripheral blood lymphocytes (PBLs) with a variety of erythrocytes from different species. The outcome indicates guinea pig and human erythrocytes formed the most rosettes, and the stimulation of the PBLs resulted in more rosette formations.

Characteristic of Erythrocyte Rosette formation

• The researchers have defined the characteristics of Erythrocyte rosette (ER) formation in equine peripheral blood lymphocytes (PBLs). The ER formation refers to the ability of PBLs to bind with erythrocytes, creating a ‘rosette’ formation around the lymphocyte.
• The researchers used erythrocytes from various species including guinea pig, human, cat, cow, dog, hamster, mouse, rat, and sheep and found that rosetting properties were prominent in guinea pig and human erythrocytes. In contrast, erythrocytes from animals such as cat, cow, dog, hamster, mouse, rat, and sheep showed negligible rosetting properties.

Assay conditions

• The conditions of the assay were modified in order to determine the procedure that yielded the largest percentage of rosette formation.
• The PBLs from 20 normal horses were tested under this optimized condition, and the researchers found an average of 38 +/- 2% of rosette formation.

Cell specific Rosette receptor

• To explore if the erythrocyte receptor is on T or B cells, equine thymocytes (immature T cells) from 6 foals were evaluated. The average rosette formation found with thymocytes was 66 +/- 5%. This suggests that the receptor for erythrocytes, which leads to rosette formation, might be more likely located on T cells than B cells.

Mixed assays

• In order to expand their understanding, the researchers conducted mixed ER and erythrocyte-antibody-complement rosette assays and noticed that none of the PBLs bound both ER and erythrocyte-antibody-complement rosettes. This suggests that different mechanisms may be at play in erythrocyte rosette formation and erythrocyte-antibody-complement rosette formation.

Impact of stimulation on rosette formation

• Finally, the research article highlights that stimulation of the PBLs with a mitogenic agent known as phytohemagglutinin resulted in more rosette formations (69 +/- 2%) compared to non-stimulated, control PBLs (42 +/- 3%).”
• The increase in rosette formation could be attributed to the activation of the lymphocytes by phytohemagglutinin which would increase the propensity of the cells to engage in rosette formation.