TABLE 1 

Immunodominant B cell epitopes of C. trachomatis and C. pneumoniae

PeptideaSequencebPooled human seraMouse serum statusePeptide sequence % identityProbability of cross- reactivity (Pcross)
Reactivity scorecRankdC. trachomatis strainfC. pneumoniae straingC. suis or C. muridarumhChlamydia spp.i
CtrOmpA_313-339IFDTTTLNPTIAGAGDVKTGAEGQLGD10.31+74<400.550.01
CtrOmpA_226-265NVLCNAAEFTINKPKGYVGKEFPLDLTAGTDAATGTKDAS8.05+94550.890.09
CtrOmpA_152_167SFNLVGLFGDNENQKT5.427+76500.290.04
CtrOmpA_82-105FQMGAKPTTDTGNSAAPSTLTARE3.939+64400.060.01
CtrCT442_135-150VVESLSRRNSLVDQTQ8.9299<400.010.01
CtrIncE_81-120LFAISALDVLEDHGLVGCPFKLPCKSSPANEPTVQFFKGK8.43+97<400.020.01
CtrIncE_117-132FKGKNGSADKVILVTQ6.51797<400.010.01
CtrPmpD_727-742EKVEEVEPAPEQKDNN8.24100<400.010.01
CtrPmpD_536-565ARAPQALPTQEEFPLFSKKEGRPLSSGYSG7.76+100<400.010.01
CtrPmpD_1036-65SGTPVQQGHAISKPEAEIESSSEPEGAHSL6.814+98<400.010.01
CtrPmpD_760-775QALFASEDGDLSPESS6.61699<400.010.01
CtrTarP_151-180SSNYDDAAADYEPIRTTENIYESIGGSRTS7.4795<400.010.01
CtrTarP_116-145TSSSDHIPSDYDDVGSNSGDISNNYDDVGS6.32177<400.010.01
CtrTarP_63-78TVVNYTNSASAPNVTV4.43394<400.010.01
CtrTarP_406-421FSKFSGDWDSLVEPMV3.74090<400.070.01
CtrCT618_185-206GNLKQNKPTEGTSKENGFMARL7.4899<400.010.01
CtrCT618_58-73TVSETQQQQLSTIETT5.031+100<400.040.01
CtrCT618_101-122KTNPDGSFQLDPVSQQRTLLSP4.23798<400.390.01
CtrCT143_2-27KKPVFTGGAPIPGISTEEGTGVKDQN7.39100<400.200.01
CtrCT529_200-239SAERADCEARCARIAREESLLEVPGEENACEKKVAGEKAK7.310+96<400.010.01
CtrCT529_17-32KAFFTQPNNKMARVVN4.03897440.160.02
CtrCT529_105-120SHMKAASQKTQEGDEG3.44296<400.010.02
CtrCT813_235-264AIENLDEMAYEAMEFEKEKHGIKPGRRGSI7.21197<400.010.01
CtrCT813_203-232TVTDLEAAKQQLEEKVTDLESEKQELREEL6.023100<400.010.01
CtrCT875_398-427KGSTHRYAPRDDLSPEGASLAETLARFADD5.924100<400.030.01
CtrCT795_148-163IMDITEIPSINPEFVE7.01299<400.020.01
CtrCT223_5-34ALGTSNGVEANNGINDLSPAPEAKKTGSGL7.01397<400.010.01
CtrPmpC_483-498APSLTEAESDQTDQTE6.815100<400.010.01
CtrPmpC_608-637AIVESTPEAPEEIPPVEGEESTATEDPNSN6.42099<400.010.01
CtrPmpC_272-301ETEQTESNGNQDGSSETEDTQVSESPESTP4.53299<400.010.01
CtrPmpC_1299-14EEQNNNDASNQGESAN3.74198<400.010.01
CtrIncG_108-147RPSDQQESGGRLSEESASPQASPTSSTFGLESALRSIGDS6.518+98<400.010.01
CtrIncG_97-112KRSPEEIEGAARPSDQ6.419100<400.020.01
CtrIncG_149-164SGAFDDINKDNSRSRS5.330100<400.010.01
CtrCT579_256-286ALDDVAGTATAVGAKATSGAASAASSAATK5.625100420.520.03
CtrCT579_100-129AQAVHGARDSGFNSDGSATLPSPTGTEVNG2.145100<400.690.01
CtrLcrE_392-421RSSFSSTPPHAPVPQSEIPTSPTSTQPPSP5.42699<400.020.04
CtrLcrE_242-271ATWEDKNHLVPCWDEETKTYNKPLLFIQML2.943100<400.160.01
CtrCT875_228-257NDPLGRRTPNYQSKNPGEYTVGNSMFYDGP5.428100<400.520.01
CtrCT875_486-515QGHYQDPRASDYDLPRASDYDLPRSPYPTP5.429100<400.240.02
CtrIncA_234-273SKTLTSQIALQRKESSDLCSQIRETLSSPRKSASPSTKSS4.334100<400.010.01
CtrCT694_64-93NRGTTTTPSRPVITQANIHHPTISGQGAQP4.23693<400.060.01
CtrCT694_267-296ENEEMNQLILGDQNGQDPQHVQDNSKELQK2.54493<400.050.01
CtrCT226_147-176AQKSKDLELAQKKIEQLQSGLKCVLEESLI4.23597<400.010.02
CtrHsp60_519-544TEALIAEIPEEKPAAAPAMPGAGMDY6.322100810.950.74
CtrHsp60_338-367EKEALEARCESIKKQIEDSSSDYDKEKLQE0.248100700.890.69
CtrpGP3_37-66GTKSTPVAAKMTASDGISLTVSNNSSTNAS2.04696<400.240.07
CtrpGP3_198-227SSGVPNLCSLRTSITNTGLTPTTYSLRVGG0.94797<400.610.61
CpnIncA_331-370QKAESEFIACVRDRTFGRRETPPPTTPVVEGDESQEEDEG3.51+<40950.010.01
CpnPmpG/I_1223-38HGQVSYGRNHHNMTTK4.62<401000.010.04
CpnPmpG/I_947-62AGTTLETTTTNNTDGS5.23<401000.010.04
CpnPmpG/I_714-729INNTAKRSGGGIYAPK6.59631000.200.29
CpnPmpG/I_222-237TATDKGGGIYSKEKDS5.71444980.010.02
CpnPmpD_1131-70NKEETLVSAGVQINMSSPTPNKDKAVDTPVLADIISITVD1.74+<401000.010.01
CpnPmpD_521-536RSNPKLEQKDSGENIN1.55<401000.010.01
CpnPmpD_654-693EKSLNACSHGDHYPPKTVEEEVPPSLLEEHPVVSSTDIRG1.310+<401000.010.01
CpnPmpD_147-186EKISSDTKENRKDLETEDPSKKSGLKEVSSDLPKSPETAV0.212+<401000.010.01
CpnCT618_201-216PETISDPENRNKPSAE0.26+<401000.010.01
CpnOmpA_158-173FGVKGTTVNANELPNV0.27+<40960.010.07
CpnOmpA_309-324AVLNLTAWNPSLLGNA0.215+<40980.010.64
CpnOmpA_89-104PTGSAAANYTTAVDRP016+<40980.010.46
CpnOmpA_242-257VAFPLPTDAGVATATG017+<401000.010.16
CpnPmpG_888-903LLRGSNNYVYNSNCEL3.38<401000.010.01
Cpn0525_239-254AQENSTAKRRRRRAAV4.811631000.290.46
CpnYscC_77-92HTKKTTPGSIPSKVFS2.113<401000.010.01
CpnCT529_236-275RAKESLYNERCALENQQSQLSGDVILSAERALRKEHVATL1.518+<401000.010.01
  • a A set of 48 C. trachomatis (Ctr) and 18 C. pneumoniae (Cpn) peptide antigens with highest reactivity is shown. Included are 10 each of previously identified C. trachomatis and C. pneumoniae mouse serum-reactive host-independent peptides (39) and 46 top-ranked host-dependent peptides identified in this investigation by screening 424 mouse nonreactive peptides.

  • b Only the actual chlamydial sequence of peptide antigens is shown, without the N-terminal biotin or the serine-glycine-serine-glycine spacer that is attached to each peptide (39).

  • c Reactivity scores are weighted averages of seven values corresponding to the reactivities of total and subpooled sera as described in Materials and Methods.

  • d The rank of each peptide within the list of 48 C. trachomatis or 18 C. pneumoniae B cell epitopes is shown. C. trachomatis rank is based on reactivity score, and C. pneumoniae rank is based on reaction frequency with 48 individual sera shown in Fig. 6.

  • e Reactivity (+) or lack of reactivity (−) with C. trachomatis-specific or C. pneumoniae-specific hyperimmune mouse sera is shown (39).

  • f Average percent amino acid sequence identity with 22 strains representing all major clades of C. trachomatis (Table S2) is shown. Sequences with identities below 40% typically cannot be aligned correctly, and the probability of peptide cross-reactivity is less than 1% (39).

  • g Average percent amino acid sequence identity with 6 major strains of C. pneumoniae (Table S2) is shown.

  • h Maximum probability of cross-reactivity (39) with C. muridarum- or C. suis-specific sera based on sequence identity (Table S2) is shown.

  • i Maximum probability of cross-reactivity (39) with sera specific for the remaining 8 Chlamydia spp. (Table S2) is shown.