Engineering selection stringency on expression vector for the production of recombinant human alpha1-antitrypsin using Chinese Hamster ovary cells

Table 3 Growth and rhA1AT productivities of top 2 cell pools from each vector set ^#

MTX concentration	Vector	Pool 1				Pool 2				Average
MTX concentration	Vector	Max titer ^% (mg/l)	q _p (pcd)	t _D (h)	Fold titer increase ⁺	Max titer ^% (mg/l)	q _p (pcd)	t _D (h)	Fold titer increase ⁺	Max titer ^% (mg/l)	q _p (pcd)	t _D (h)
50 nM	pAID	256	17.6	46	5.6					256	17.6	46
	pAIDp	492	25.7	36	4.2	244	10.9	36	3.1	368	18.3	36
	pAIDpp	647	29.0	33	4.4	539	25.9	44	5.4	593	27.5	39
	pAI772Dp	1054	41.3	28	8.5	937	33.8	26	8.2	996	37.6	27
	pAID*	275	14.4	41	3.1	170	7.8	40	2.2	222	11.1	40
	pAID*p	277	8.4	33	2.0					277	8.4	33
300 nM	pAID	560	32.5	34	2.2					560	32.5	34
	pAIDp	514	25.8	33	1.0	240	13.1	37	1.0	377	19.5	35
	pAIDpp	1146	88.2	45	1.8	846	41.9	41	1.6	996	65.0	43
	pAI772Dp	1111	48.6	42	1.1	863	35.4	27	0.9	987	42.0	34
	pAID*	721	34.3	43	2.6	398	22.1	33	2.3	559	28.2	38
	pAID*p	412	17.7	29	1.5					412	17.7	29

^#The 2 cell pools that gave the highest titers in 96 well-plate adherent culture with 50 nM MTX were chosen for further amplification to 300 nM MTX. The 50 nM and 300 nM MTX cell pools were then adapted to serum-free suspension culture in shake flasks to evaluate their growth and rhA1AT production profiles. The top producing cell pool in 96-well plate format (Figure 2) is indicated as Pool 1. Only 1 cell pool from vectors pAID and pAID*p survived the adaptation to suspension culture or the MTX amplification process respectively.
^%Maximum titer was taken as the highest rhA1AT titer assayed from the first 11 days of the batch culture.
⁺Fold titer increase for cell pools in 50 nM MTX suspension culture was compared against the titers of the same cell pools in adherent 96 well plate cultures, whereas that for cell pools in 300 nM MTX suspension culture was compared against the titers of the same cell pools in 50 nM MTX suspension culture.

ISSN: 1472-6750