TABLE 1.

Peptides used to screen for IR-specific monoclonal antibodies

Peptidea	Sequenceb	Length	Variability (z-score)d
IR1	EVSELLDKLVKAVKTAEGASSG	22	−0.1746
IR2	(ASVK)GIAKGIKEIVEAA(GGSE)	21	−0.6066
IR3c	AGKLFVK	7	−0.6585
IR4	KAAGAVSAVSGEQILSAIV(TAA)	22	−0.5393
IR5	(AEEAD)NPIAAAIG(TTNEDA)	19	−0.7378
IR6	MKKDDQIAAAIALRGMAKDGKFAVK	25	−0.6932

^aIRs: Invariant regions. Six IRs were identified from an alignment of VlsE proteins from three strains representing two species (18).

^bIR sequences were based on the VlsE protein of the B31 strain (GenBank accession U76405). Flanking residues (in parentheses) were padded to the IR2 and IR4 to facilitate ELISA. For IR5, the padded residues were the most common residues flanking this conserved region.

^cAntigenicity of IR3, the shortest IR, was not tested in the present study.

^dStandard deviation from the mean amino-acid substitution rate of zero, with a lower score indicating a higher level of sequence conservation (see Materials and Methods).