The number of splenocytes expressing CD3 molecules on their surface in a specified sample of spleen, the highly vascular lymphoid organ which serves to store blood, disintegrate old blood cells, filter foreign substances from the blood, and produce lymphocytes.. The CD3 complex, including five CD3 subunits, binds either TCR alpha/beta or TCR gamma/delta to form the TCR/CD3 complex on the surface of T-cells.