Expression of PLCγ1 at the external leaflet of the plasma membrane in T-cell subsets. PBMCs were double-stained with anti-PLCγ1, evidenced by a FITC-conjugated secondary antibody, and with either PE-labeled anti-CD4, anti-CD8, anti-CD45RA, or anti-CD45RO antibody. (A) Results showed that the enzyme is expressed on the membrane of CD8⁺ cells (29.2% ± 5.1%), while the percentage of circulating PLCγ1⁺CD4⁺lymphocytes is very low (1.1% ± 0.2%, P < .05). (B) When expression of the enzyme on naive and memory cells was considered, PBMCs displayed a significant percentage of PLCγ1⁺CD45RA⁺ (27.2% ± 1.7%), whereas the phenotype PLCγ1⁺CD45RO⁺was slightly detectable (4.2% ± 0.6%, P < .005). Significance of the results was determined by Student's ttest. n = 10 samples.