Co-cultures of pericytes (1 × 105) and GBM cells in 1:1 proportion, were plated in 96 well plate. Pericytes and GBM cells cultures were used as controls. After 72 hours, T cells (5×104) were plated on attached pericytes or attached GBC-PC previously, in 96 well plate, in 5:1 proportion respectively and in presence or not of OVA323-339 peptide antigen (Sigma-Aldrich). Pericytes were detached with trypsin 0.05% after 72 hours and plated with T cells at the same time to confirm the same results. For suppression assay of T cell function, splenocytes and T cells were plated in 96 well plates, in 5:1 proportion, in presence or not of OVA323-339 peptide on GBC-PC or pericytes plated 72 hours before. In some cases, media from cultures of GBC-PC, control pericytes and control GBM cells for 72 hours, was recollected to add to stimulated T cells with plate-bound antibodies.