Table 1.

Summary of immunological studies reporting SARS-CoV-2 T cell epitopes targeted in individuals recovered from COVID-19 (as of April 20, 2021)

No.	Studya	Geography (Country)	Total Individuals	Gender (Female/Male)	Median Age (Range)	Disease Severityb (Asymptomatic or Mild)	Disease Severityb (Moderate or Severe)		Blood Collection Time (Days)c	Initial Peptide Selection Procedured	Proteins	Total Peptides Tested	T cell Assay	Total Distinct Epitopes Identified
1	Saini et al.14	Denmark	18	6/12	43.5 (29–82)	7		11	As close as possible to the first positive test	NetMHCpan-4.1	all	2,204	multimer qualitative binding	122
2	Kared et al.15	Baltimore/ Washington, USA	30	12/18	42.5 (19–77)	N/A		N/A	27–62 after symptom resolution	Grifoni et al.;16 Prachar et al.17	all	408	multimer qualitative binding	46
3	Schulien et al.18	Germany	26	14/12	32.5 (24–56)	26		0	24 (14–70) after symptom onset	ANN-4.0, SARS-CoV epitopes16	S, N, M, ORF1ab, ORF3a	66	multimer qualitative binding	37
4	Poran et al.19	N/A	3	N/A	N/A	N/A		N/A	N/A	HLAthena	all	23	multimer qualitative binding	11
5	Shomuradova et al.20	Moscow, Russia	31	16/15	35 (17–59)	21		10	33 (17–49) after positive test/after disease onset	NetMHCpan-4.0 and identity with SARS-CoV > 60%	S	13	multimer qualitative binding	10
6	Nielsen et al.21	Denmark	203	92/111	47 (21–79)	17		186	44 (14–129) after symptom onset	N/A	S, N, M	9	multimer qualitative binding	9
7	Chour et al.22	USA	2	0/2	50 (30–70)	0		2	6.5 (2–13) post symptom onset	NetMHC-4.0	S	96	multimer qualitative binding	6
8	Sekine et al.23	Sweden	66	14/41	51	40		26	53.5 (IQR: 45.5–61) after symptom onset	NetMHCpan-4.1	all	13	multimer qualitative binding	4
9	Nguyen et al.24	Melbourne, Australia	7	1/6	32 (19–74)	6		1	90 (5–145) after disease onset	overlapping peptide pools and 5 N-specific immunogenic peptides25,18,26,27	S, N, M	N/A	ICS IFN-γ release; multimer qualitative binding	3
10	Rha et al.28	South Korea	37	18/19	46 (21–83)	23		14	46 (19–125) after symptom onset	N/A	S, N, M	8	multimer qualitative binding	2
11	Ferretti et al.26	New Jersey/Louisiana, USA	78	55/23	19.5 (0–80)	55		23	49 (11–111) post diagnosis	identification of 20-mer peptides by TScan screen29 followed by NetMHC-4.0	all	~240	Single-allele ELISA IFN-γ; multimer qualitative bindinge	28
12	Nelde et al.30	Germany	116	55/61	44 (18–75)	36		80	37.7 (19–52) after positive test	SYFPEITHI-1.0, NetMHCpan-4.0	all	120	ICS IFN-γ release; ELISPOT IFN-γ release	47
13	Hu et al.31	Chongqing, China	37	16/21	47 (20–67)	34		3	N/A	NetMHCpan-4.0, SARS-CoV epitopes32,16	S, N	78	ELISPOT IFN-γ release	15
14	Habel et al.25	Melbourne, Australia	18	10/8	54 (22–76)	11		7	47 (36–102) after disease onset	NetCTLpan, NetMHCpan	S, N, M, ORF1ab	14	ICS IFN-γ release	14
15	Lineburg et al.33	Queensland, Australia	37	23/14	51 (20–75)	7		5	62 (46–124) after positive test	overlapping peptide pools followed by peptide matrix analysis	all	N/A	ICS IFN-γ release	4
16	Lee et al.34	New South Wales, Australia	2	N/A	N/A	0		2	30–60 after symptom resolution	Network analysis35 followed by NetMHCpan-4.1 and NetMHCIIpan-4.0	S, N	2	ICS IFN-γ release	2
17	Tarke et al.36	San Diego, USA	99	58/41	41 (19–91)	90		9	67 (3–184) after symptom onset	NetMHCpan-4.0	all	7,525	AIM assay37	803
18	Peng et al.27	UK	42	16/26	57 (20–95)	28		14	42 (30–62) after symptom onset	15- to 18-mer peptides overlapping by 10 residues, SARS-CoV epitopes32	all except ORF1	450	ELISPOT IFN-γ release	46f

^aStudies reporting precise epitopes along with the cognate HLA information.

^bDefinition of disease severity varies among studies.

^cIQR, interquartile range.

^dNetCTLpan,³⁸ NetMHC-4.0,³⁹ NetMHCpan,⁴⁰ NetMHCpan-4.0,⁴¹ NetMHCpan-4.1,⁴² SYFPEITHI-1.0,⁴³ ANN-4.0,⁴⁴ and HLAthena.⁴⁵

^eSix (of 28) epitopes were identified using multimer qualitative binding.

^fOnly two (of 46) epitopes that were reported as precise epitopes with the cognate HLA information were considered.