Table 5.

Immune responses in volunteers receiving NS and PfSPZ Vaccine before the first immunization and 2 weeks after the third immunization

Group	Volunteer ID	ELISA PfCSP OD 1.0				aIFA AFU 2 × 105				ISI reciprocal serum dilution for 80% inhibition
		Pre-immune*	Immune†	Net‡	Ratio§	Pre-immune*	Immune†	Net‡	Ratio§	Pre-immune*	Immune†	Net‡	Ratio§
NS	201	188	342	154	1.82	0	73	73	73.00	4.91	21.33	16.41	4.34
	222	192	278	86	1.45	0	71	71	71.00	15.31	16.31	0.99	1.06
	225	38	37	−1	0.97	73	345	272	4.73	13.72	2.60	−11.13	0.19
	232	102	158	56	1.55	54	81	27	1.50	0.00	8.83	8.83	8.83
	235	62	158	96	2.55	127	216	89	1.70	13.76	14.11	0.36	1.03
	241	167	133	−34	0.80	0	39	39	39.00	9.36	12.88	3.52	1.38
	251	654	481	−173	0.74	138	0	−138	0.00	17.43	3.75	−13.69	0.21
	253	45	47	2	1.04	19	104	85	5.47	10.17	21.02	10.84	2.07
	256	95	210	115	2.21	0	238	238	238.00	13.15	25.61	12.46	1.95
	258	39	40	1	1.03	0	372	372	372.00	7.31	7.55	0.23	1.03
	Median	99	158	29	1.25	19	93	79	22.24	11.66	13.50	2.26	1.22
PfSPZ Vaccine	203	46	808	762	17.57	0	270	270	270.00	0.00	9.93	9.93	9.93
	204	328	551	223	1.68	134	122	−12	0.91	12.51	28.69	16.18	2.29
	206	275	412	137	1.50	212	268	56	1.26	16.05	5.75	−10.29	0.36
	212	172	1,472	1,300	8.56	18	252	234	14.00	8.60	67.53	58.93	7.85
	215	77	603	526	7.83	88	488	400	5.55	0.00	14.06	14.06	14.06
	217	85	938	853	11.04	74	470	396	6.35	4.55	20.71	16.15	4.55
	218	89	736	647	8.27	82	254	172	3.10	13.55	31.99	18.44	2.36
	226	311	381	70	1.23	259	340	81	1.31	5.65	2.44	−3.22	0.43
	227	525	536	11	1.02	417	293	−124	0.70	12.67	27.71	15.04	2.19
	229	237	1,314	1,077	5.54	127	538	411	4.24	21.80	33.79	11.99	1.55
	231	118	1,547	1,429	13.11	84	404	320	4.81	0.00	39.64	39.64	39.64
	233	199	1,472	1,273	7.40	59	706	647	11.97	0.00	20.32	20.32	20.32
	236	62	198	136	3.19	299	292	−7	0.98	3.07	20.03	16.96	6.52
	242	47	755	708	16.06	16	341	325	21.31	21.38	39.39	18.01	1.84
	243	188	1,115	927	5.93	0	329	329	329.00	15.27	5.53	−9.74	0.36
	244	23	240	217	10.43	0	151	151	151.00	0.00	11.18	11.18	11.18
	249	106	219	113	2.07	71	147	76	2.07	10.95	18.46	7.51	1.69
	250	47	1,112	1,065	23.66	3	512	509	170.67	21.35	46.07	24.72	2.16
	252	236	2,650	2,414	11.23	44	272	228	6.18	8.13	27.76	19.63	3.41
	257	42	90	48	2.14	45	107	62	2.38	22.56	19.12	−3.43	0.85
	Median	112	746	678	7.61	72	292	231	5.18	9.77	20.51	15.60	2.33

AFU = arbitrary fluorescence units; aIFA = automated immunofluorescence assay; ELISA = enzyme-linked immunosorbent assay; ISI = inhibition of sporozoite invasion assay; NS = normal saline; PfCSP = Plasmodium falciparum circumsporozoite protein; PfSPZ = P. falciparum sporozoites; Volunteer ID = volunteer identification number. Immune responses were measured in all Group 2 and Group 3 volunteers using PfCSP ELISA, aIFA, and ISI assays. Those in bold were considered to have developed antibodies after immunization.

^*Pre-immune sera taken before the first immunization.

^†Immune sera taken 2 weeks after the last immunization.

^‡Net = immune–pre-immune value.

^§Ratio = immune/pre-immune value. All values of 0 were changed to 1 when calculating ratios.