Identification and characterization of a porcine‐specific transferrin receptor in <i>Actinobacillus pleuropneumoniae</i>

Gonzalez, Guido C.; Caamano, D. L.; Schryvers, A. S.

doi:10.1111/j.1365-2958.1990.tb00692.x

Cited by 80 publications

(51 citation statements)

References 14 publications

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“…The ability to maintain or reconstitute binding activity by native Tbp2 after SDS-PAGE and electroblotting (Gonzalez et al, 1990), in conjunction with these results, indicate that binding alone is not an adequate indicator of native conformation of the Tbp2 protein. We used the proteolytic cleavage of intact proteins as an alternative procedure to assess conformation but did not detect any stable intermediates in our preliminary attempts.…”

Section: Discussionmentioning

confidence: 73%

“…The transferrin receptor in the porcine pathogen, Actinobacilltls pleuropnezlmoniae, is similarly composed of two proteins, Tbpl and Tbp2, and is specific for porcine transferrin (Gonzalez et al, 1990). The genes encoding the Tbp2 (TfbA) proteins from two strains of A. pletlropnetlmoniae have been cloned and characterized (Gerlach e t al., 1992a, b) but these experiments did not include information on the presence of the t b p A genes or the organization of the tbp genes.…”

Section: Introductionmentioning

confidence: 99%

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Sequence, genetic analysis, and expression of Actinobacillus pleuropneumoniae transferrin receptor genes

Gonzalez

Rosteck

et al. 1995

Microbiology

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The tbpA and *pi? genes encoding the transferrin receptor proteins T b p l and Tbp2 from a serotype 7 strain of Actinobacillus pleuropneumoniae were cloned, sequenced, and expressed in Escherichia coli. The tbpB gene was preceded by putative promoter and regulatory sequences and was separated from the downstream tbpA gene by a 13 bp intercistronic sequence suggesting that the two genes may be coordinately transcribed. Determination of the nucleotide sequence of this region facilitated PCR amplification of the tbp region from a serotype 1 strain for comparative purposes. The deduced amino acid sequences of the T b p l proteins had regions of homology with Neisseria Lbp and Tbpls and with TonB-dependent outer membrane (OM) receptors of E. coli. The deduced amino acid sequences of the Tbp2 proteins were nearly identical to those presented in previous studies. Upon high-level expression of the tbpA gene, a large proportion of the recombinant T b p l was found in inclusion bodies and could not be aff inity-isolated with immobilized porcine transferrin. Most of the remaining expressed T b p l was present in the OM fraction, was expressed at the surface of E. coli cells, and retained binding activity that was specific for the Globe of porcine transferrin. Although recombinant Tbp2 was found in inclusion bodies during high-level expression, a significant proportion was associated with a novel OM fraction that appeared in sucrose density gradients which was distinct from the OM fraction containing recombinant Tbpl. The recombinant Tbp2 was accessible at the surface yet was unable to bind porcine transferrin. In contrast to previous observations, the binding by recombinant Tbp2 was specific for the Globe of porcine transferrin. These results indicate that the A. pleuropneumoniae transferrin receptor proteins have similar properties to the receptor proteins in Neisseria spp. and Haemophilus influenzae, and that functional studies performed with recombinant receptor proteins need to consider differences in processing and export of these proteins when expressed in heterologous hosts.

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Section: Discussionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Sequence, genetic analysis, and expression of Actinobacillus pleuropneumoniae transferrin receptor genes

Gonzalez

Rosteck

et al. 1995

Microbiology

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“…plezlropnezlmoniae has previously been shown to bind and acquire iron from porcine transferrin but not from human or other mammalian transferrins (Morton & Williams, 1989Gonzalez et al, 1990). On dot blots, A. pletrropneumoniae strains belonging to serotypes 1, 3, 5 and 7 bound biotinylated porcine but not human or bovine transferrins (data not shown).…”

Section: Antigenic Relationships Amongst the Tbps Of A Pleuropneumonmentioning

confidence: 99%

Conservation and antigenic cross-reactivity of the transferrin-binding proteins of Haemophilus influenzae, Actinobacillus pleuropneumoniae and Neisseria meningitidis

et al. 1996

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Haemophilus influenzae acquires iron from the iron-transporting glycoprotein transferrin via a receptor-mediated process. This involves two outer-membrane transferrin-binding proteins (Tbps) termed T b p l and Tbp2 which show considerable preference for the human form of transferrin. Since the Tbps are attracting considerable attention as potential vaccine components, we used transferrin affinity chromatography to examine their conservation amongst 28 H. influenzae type b strains belonging to different outer-membrane-protein subtypes as well as six non-typable strains. Whole cells of all type b and nontypable strains examined bound human transferrin; whilst most strains possessed a T b p l of approximately 105 kDa, the molecular mass of Tbp2 varied from 79 to 94 kDa. Antisera raised against affinity-purified native H. influenzae TbpllTbp2 receptor complex cross-reacted on Western blots with the respective Tbps of all the Haemophilus strains examined. When used to probe Neisseria meningitidis Tbps, sera from each of four mice immunized with the Haemophilus TbplR complex recognized the 68 kDa Tbp2 of N. meningitidis strain B16B6 but not the 78 kDa Tbp2 of N. meningitidis strain 70942. Serum from one mouse also reacted weakly with T b p l of strain B16B6. Apart from a weak reaction with the Tbp2 of a serotype 5 strain, this mouse antiserum failed to recognize the Tbps of the porcine pathogen A. pleuropneumoniae. However, a monospecif ic polyclonal antiserum raised against the denatured Tbp2 of Neisseria meningitidis B16B6 recognized the Tbps of all Haemophilus and Actinobacillus strains examined. Since H. influenzae forms part of the natural flora of the upper respiratory tract, human sera were screened for the presence of antibodies to the Tbps. Sera from healthy adults contained antibodies which recognized both T b p l and Tbp2 from H. influenzae but not N. meningitidis. Convalescent sera from meningococcal meningitis patients contained antibodies which, on Western blots, recognized the Tbps2s of both pathogens. These data demonstrate the existence of shared epitopes on the Tbps of H. influenre, N. meningitidis and A. pleuropneumoniae despite their transferrin species specificity.

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“…However, the pathogenic Neisseria species do not synthesize siderophores (1,26,50). Neisseria meningitidis (1,26,43,45), Neisseria gonorrhoeae (24,26), and certain other bacterial species (12,17,27,30,31,36) are capable of direct utilization of Tf as their sole source of iron in the apparent absence of siderophore production. Meningococci and most, although not all, gonococcal isolates can also use Lf as a sole iron source (25).…”

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confidence: 99%

Gonococcal transferrin-binding protein 2 facilitates but is not essential for transferrin utilization

1994

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Identification and characterization of a porcine‐specific transferrin receptor in Actinobacillus pleuropneumoniae

Cited by 80 publications

References 14 publications

Sequence, genetic analysis, and expression of Actinobacillus pleuropneumoniae transferrin receptor genes

Sequence, genetic analysis, and expression of Actinobacillus pleuropneumoniae transferrin receptor genes

Conservation and antigenic cross-reactivity of the transferrin-binding proteins of Haemophilus influenzae, Actinobacillus pleuropneumoniae and Neisseria meningitidis

Gonococcal transferrin-binding protein 2 facilitates but is not essential for transferrin utilization

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