Characteristics of major outer membrane proteins of Haemophilus influenzae

Abstract

Several properties of Haemophilus influenzae outer membrane proteins were analyzed to define related proteins in various isolates. H. influenzae type b 760705 had six major outer membrane proteins with the following characteristics. Protein a (Mr, 47,000) demonstrated heat modifiability in sodium dodecyl sulfate; its apparent molecular weight was 34,000 at temperatures below 60°C. This protein was extracted from cell envelopes by using Triton X-100-10 mM MgCl2; in cell envelope preparations, the protein was degraded by trypsin. Proteins b (Mr, 41,000) and c (Mr, 40,000) were insensitive to trypsin degradation, were not heat modifiable in sodium dodecyl sulfate, and were peptidoglycan associated in 0.5% Triton X-100-0.2% sodium dodecyl sulfate. The amount of protein b was reduced in ultrasonically obtained cell envelopes. Protein d (Mr, 37,000) was heat modifiable in sodium dodecyl sulfate with an Mr of 28,000 at temperatures below 100°C and was degraded by trypsin, leaving a membrane-bound fragment of Mr, 27,000. Both the intact and degraded proteins were immunologically crossreactive with the heat-modifiable OmpA protein of Escherichia coli K-12. Protein d was absent in LiCl-EDTA extracts of cells. Protein e (Mr, 30,000), invariably present in all H. influenzae strains tested, was insensitive to trypsin and absent in LiCl-EDTA extracts of cells. Protein k (Mr, 58,000) was extracted from cell envelopes with 2% Triton X-100-10 mM MgCI2 and, in cell envelopes, appeared to be sensitive to trypsin degradation. Proteins with similar properties to those of proteins a to k were found in 10 other H. influenzae b strains, reference strains with serotype a, c, d, e, and f capsules, and 18 of 20 nonencapsulated strains. Their relative molecular weights, however, varied.

The Anton blood group antigen is the erythrocyte receptor forHaemophilus influenzae

“…This approach opens up the possibility of preventing serious H.influenzae infections, including meningitis, epiglottitis, recurrent sinusitus and otitis media, and chronic bronchitis, by interfering with the interaction between the receptor site and the bacteria, thus preventing its adherence to and colonisation 71 of the mucosa. This interaction seems to be common for various H.influenzae strains, despite the strongly varying antigenic composition of their surface-exposed components [7].…”

The capsular polysaccharide ofHaemophilus influenzaetype B prevents killing by complement and antibodies against outer membrane proteina

“…It shows that the killing-promoting antibodies were removed by absorption with purified protein a, with cells of the homologous strain 760705, but not with purified lipopolysaccharide, polysaccharide or cells of strain 1481. This strain has a protein a with a different molecular mass and immunological properties than strain 760705 ( [5], L. van Alphen Table 2 Relation between titres of antibodies against protein a, lipopolysaccharide and polysaccharide of variously absorbed anti-a sera and killing of strain 760705b ° et al, Submitted for publication). Reduction in killing coincided with a strong reduction in antiprotein a titre and not with reduction in anti-lipopolysaccharide.…”

“…The H. influenzae type b strains used throughout this study were isolated from the CSF of patients with meningitis. Their (sub) typing characteristics have been described before [4,5] and are summarised in Table 1. Strain 1481 was a non-typable strain isolated from sputum of a patient with a respiratory tract infection.…”

“…The cells were harvested by centrifugation, washed twice in PBS and counted in a gamma counter to determine the amount of bound antibodies. Control assays were performed in the absence of antibodies and with cells of H. influenzae strain 1481, which has a different protein a [5].…”

Interaction of clinical isolates of nonencapsulated Haemophilus influenzae with mammalian extracellular matrix proteins

“…H. in£uenzae was identi¢ed by its dependence for growth factors X and V and its inability to convert Naminolevulanic acid to porphyrins [19]. The strains were characterized phenotypically by major outer membrane protein (MOMP) subtyping as described previously [20]. In addition, genotypic characterization was performed by randomly ampli¢ed polymorphic DNA (RADP) analysis with the primers ERIC1 and ERIC2 as described before [21].…”