Table IV.

COMPARISON OF INTESTINAL AND RESPIRATORY PRIMARY AND MEMORY ASC RESPONSES INDUCED BY VIRULENT TGEV AND LOW VERSUS HIGH DOSES OF ATTENUATED TGEV IN NEONATAL PIGS^a

		Mean No. ASC/5 × 105 MNC
Virus inoculum group/responseb		Mesenteric lymph node			Bronchial lymph node
		IgG	IgA	G/Ac	IgG	IgA	G/Ac
Virulent TGEV	Primary	48	9	5	7	1	7
	Memory	5295	1159	5	2989	327	9
Attenuated TGEV
Low dose (106 pfu)	Primary	2	<1	UD	16	1	16
	Memory	60	<10	UD	866	34	25
High dose (108 pfu)	Primary	9	1	9	28	1	28
	Memory	1133	79	14	4475	159	28

^aData summarized from VanCott et al. (1993).

^bPrimary immune responses were assayed by ELISPOT directly on mononuclear cells (MNCs) obtained from pigs at PID 12 and 24 and the mean numbers of ASC per 5 × 10⁵ MNC are shown. Memory or secondary immune responses were assayed by ELISPOT after in vitro TGEV stimulation (5 days) of MNC obtained from pigs at PID 24 and 40 and the mean numbers of ASC per 5 × 10⁵ MNC are shown.

^cG/A, ratio of IgG to IgA ASCs; UD, undetermined.