TABLE 2.

IgA antibody response to homologous, cross-reacting, and heterologous antigens of patients infected with CFA/I- and CS14-expressing ETEC strains

CF of infecting ETEC strain	CF tested for HoM, CR, and HeT antigens	Parameter	Response to homologous CF				Response to cross-reacting CFs								Response to heterologous CF
			Day 2	Day 7	Day 14	Day 30	CS14				CS4				CS5
							Day 2	Day 7	Day 14	Day 30	Day 2	Day 7	Day 14	Day 30	Day 2	Day 7	Day 14	Day 30
CFA/I	CFA/I (HoM); CS14, CS4 (CR); CS5 (HeT)	GM	342	1,884	2,838	849	256	574	726	470	350	622	1,047	701	107	102	166	142
		Range	293-488	1,083-3,273	1,759-4,581	548-1,315	219-300	414-794	516-1,020	397-556	263-464	439-881	737-1,485	545-90	76-148	73-143	110-252	100-203
		P valuea
		(control)	0.003	<0.001	<0.001	0.002	<0.001	<0.001	<0.001	<0.001	NS	0.015	0.003	0.003	NS	NS	NS	NS
		P valueb
		(days)		0.006	<0.001	NS		NS	0.033	NS		NS	0.044	NS		NS	NS	NS
							CFA/I				CS4				CS5
CS14	CS14 (HoM); CFA/I, CS4 (CR); CS5 (HeT)	GM	421	1,318	601	519	390	430	490	269	251	466	130	188	26	35	37	83
		Range	331-534	996-1,798	337-1,074	347-774	250-607	248-743	282-851	194-372	183-341	361-601	97-174	129-274	16-42	21-55	26-50	53-127
		P value
		(control)	0.002	<0.001	0.014	0.008	0.015	0.038	0.028	0.045	NS	0.045	NS	NS	0.024	0.005	0.006	0.001
		P value
		(days)		0.010	NS	NS		NS	NS	NS		NS	NS	NS		NS	NS	NS

^aAntibody titers at acute (day 2) and at convalescence (day 7, day 14, and day 30) stages after onset of diarrhea in patients were compared with the levels in healthy controls.

^bTiters at different time periods at convalescence (day 7, day 14, and day 30) were compared with the titer at the acute phase (day 2) of diarrhea in the patients.