Table II.

Major glycoforms observed at the conserved N-glycosylation site of the Aβ autoantibody

	Glycoform			Glycan	Relative
Glycopeptide/subclass	assignmenta	[M+H]+exp.(Da)b	[M+H]+calc.(Da)	composition	abundancec
EEQYNSTYR (IgG1)	i	2488.010	2487.988	G0	0.04
		a	2634.040	2634.046	G0F	0.57
		k	2650.084	2650.041	G1	0.08
		b	2796.148	2796.099	G1F	1
		m	2812.124	2812.094	G2	0.06
		d	2837.176	2837.125	G0FB	0.16
		c	2958.175	2958.152	G2F	0.57
		e	2999.196	2999.178	G1FB	0.23
		h	3087.220	3087.194	G1FSA	0.04
		f	3161.268	3161.231	G2FB	0.05
		g	3249.240	3249.247	G2FSA	0.23
EEQ(Y/F)NST(F/Y)R (IgG4)	i	2472.011	2471.993	G0	0.04
		a	2618.069	2618.051	G0F	0.84
		k	2634.058	2634.046	G1	0.11
		b	2780.112	2780.104	G1F	1
		m	2796.166	2796.099	G2	0.15
		d	2821.139	2821.130	G0FB	0.28
		c	2942.186	2942.157	G2F	0.57
		e	2983.184	2983.183	G1FB	0.26
		h	3071.213	3071.199	G1FSA	0.11
		f	3145.262	3145.236	G2FB	0.08
		g	3233.292	3233.252	G2FSA	0.33
EEQFNSTFR (IgG2/IgG3)	i	2456.062	2455.998	G0	0.02
		a	2602.077	2602.056	G0F	0.83
		k	2618.074	2618.051	G1	0.03
		b	2764.131	2764.109	G1F	1
		m	2780.090	2780.104	G2	0.02
		d	2805.150	2805.135	G0FB	0.20
		c	2926.177	2926.162	G2F	0.48
		e	2967.191	2967.188	G1FB	0.16
		h	3055.225	3055.204	G1FSA	0.13
		f	3129.263	3129.241	G2FB	0.04
		g	3217.290	3217.257	G2FSA	0.22

^aThe assignment of the glycoforms corresponds to that indicated in Figures 6 and 7.

^bThe experimental [M+H]⁺ values of the glycopeptides were determined based on the observed [M+4H]⁴⁺ glycopeptide ions, as follows: two consecutive MS scans were summed and smoothed using the Savitzky Golay algorithm (feature available in the MassLynx 4.1 software) and subsequently centered, with the centroid set at 80% height of the C12-monoisotopic peak.

^cThe relative abundance of each glycoform was determined as the ratio of the observed ion abundance for each individual glycoform to that observed for the glycoform G₀F within each IgG subclass. The ion abundances for all observed charge states for a particular glycopeptide were considered.