Effects of anticoagulants on the immunological synapses of human autologous rosettes between macrophage and lymphocyte

Abstract

The contact area between a T cell and antigen-presenting cell is known as “immunological synapse” and the multiple interactions that occur leading to a “signal” for T cell activation. However, an immunological synapse can occur in different circumstances, for a variety of functions. The phenomenon of multiple immunological synapses on macrophage-lymphocyte rosette (MLR) (2, 3) refers to cellular association between human blood monocyte-derived macrophages and lymphocytes from autologous cultures total leukocytes extracted from the blood, which bind selectively forming rosettes with central macrophage and lymphocytes adhered. Inhibitors of antigen processing and presentation and monoclonal antibodies anti-Major Histocompatibility Complex Class II preclude the MLR phenomenon.

Objective: As the MLR phenomenon was originally described using heparin, we studied the use of alternative anticoagulants. Materials and methods: human blood samples, anticoagulated with EDTA (ethylenediaminetetraacetic acid) (n = 10) Sodium citrate (n = 10) and controls with heparin (n = 10) healthy samples. Autologous cultures in medium TC199 (Sigma, St. Louis, MO). Culture samples
were analysed at 72 h and 96 h. Results: In all heparin cases were observed MLRs, in sodium citrate cases, there was no viable leukocytes in cultures, and in cases with EDTA, leukocytes were observed, but the MLR phenomenon did not occur, there was no immune synapse. Conclusions: These results could be due to the chelating action of Ca2 + from the EDTA and sodium citrate as the inhibition of the leucoaccumulation of F-actin by EDTA, which affect the immune synapse in MLR phenomenon.