Table 4.

Quantification of mHA-specific Tconvs and Tregs in donor apheresis after Treg enrichment and after expansion under GMP

	Donor
	1	2	3
Total blood volume processed by apheresis (mL)	21 358	10 270	24 046
Total live mononuclear cells × 108	370	218	244
No. of Tconvs × 108 (% total)	204 (55%)	60 (28%)	32 (13%)
mHA-specific Tconvs*
Frequency (%)	0.009	0.003	0.007
n	1 861 326	190 823	238 834
No. of Tregs × 108
Before immunoabsorption (% total)	12.7 (3.4%)	4.2 (1.9%)	7.1 (2.9%)
After immunoabsorption (% yield)	3.9 (31%)	1.2 (28%)	1.1 (16%)
After freezing and thawing (% yield)	2.1 (17%)	0.83 (20%)	1.33 (16%)
Total Tregs used for expansion × 108
Before culture†	1.33	0.75	0.55
After culture	0.97	0.65	0.50
mHA-specific Tregs* before culture†
Frequency (%)	0.007	0.002	0.005
n	11 285	1842	3084
mHA-specific Tregs after culture
Frequency (%)	2.7	0.65	1.8
n	3 651 226	745 763	1 035 524
Fold expansion
Required to match CD4 T effector cells at a 1:1 ratio	165	104	77
Measured	324	405	336

^*The frequency of mHA-specific Treg or Tconv was obtained from limiting dilution analysis.

^†A fraction of the purified Tregs were cultured with DCs from an HLA-matched sibling at a 1:1 ratio with IL-2, IL-15, and rapamycin.