Epitopes of Immunoreactive Proteins of Streptococcus Agalactiae: Enolase, Inosine 5′-Monophosphate Dehydrogenase and Molecular Chaperone GroEL

Abstract

Three Streptococcus agalactiae (group B streptococci, GBS) immunoreactive proteins: enolase (47.4 kDa), inosine 5′-monophosphate dehydrogenase (IMPDH) (53 kDa) and molecular chaperone GroEL (57 kDa) were subjected to investigation. Enolase protein was described in our previous paper, whereas IMPDH and GroEL were presented for the first time. The aim of our paper was to provide mapping of specific epitopes, highly reactive with umbilical cord blood serum. Bioinformatic analyses allowed to select 32 most likely epitopes for enolase, 36 peptides for IMPDH and 41 immunoreactive peptides for molecular chaperone GroEL, which were synthesized by PEPSCAN. Ten peptides: two in enolase, one in IMPDH and seven in molecular chaperone GroEL have been identified as potentially highly selective epitopes that can be used as markers in rapid immunological diagnostic tests or constitute a component of an innovative vaccine against GBS infections.

Immunogenic Proteins of Group B Streptococcus—Potential Antigens in Immunodiagnostic Assay for GBS Detection

“…Immunoreactivity to Streptococcus agalactiae was also showed. Moreover, highly specific IMPDH GBS epitopes recognized by umbilical cord blood isolated from GBS-positive women were identified, and what is worth to underline, it was performed for the first time [101,103]. The obtained results allowed to consider them as potential antigens in an immunodiagnostic assay for GBS carriage detection.…”

“…In our previous paper, we decided to take the next step and detected epitopes representative of enolase, which specifically recognized anti-GBS IgG antibodies, and which were studied in ELISA with the presence of umbilical cord blood serum from pregnant women qualified as GBS carriers. Presently, these epitopes are being investigated as potential components in an immunodiagnostic assay for detection of GBS carriage and/or infections in pregnant women [103]. Nevertheless, consideration of enolase as a detection antigen requires taking into account the fact of relatively close sequence similarity among streptococci as well as a possibility of cross-reactivity with human enolase.…”

“…Inosine 5 -monophosphate dehydrogenase (IMPDH, dehydrogenase IMP), with a mass of 53 kDa, is a stable purine, which participates in catalysis of the key stage of de novo synthesis of the guanine and adenine nucleotides in all organisms, in other words, it is a crucial precursor for DNA and RNA synthesis [103,139,140]. IMPDH monomers contain 400-500 amino acids, and these differences depend on the presence of a subdomain that is not required for enzymatic activity.…”

“…This molecular chaperon, as well as its epitopes, have an ability to specifically bind with anti-GBS antibodies present in both umbilical cord and vascular blood [103]. Immunogenic features of GBS GroEL were also investigated for tilapia.…”

Molecular Characteristic, Antibiotic Resistance, and Detection of Highly Immunoreactive Proteins of Group B Streptococcus Strains Isolated From Urinary Tract Infections in Polish Adults

“…The detection of immunoreactive proteins was carried out by immunoblotting for 10 selected GBS strains, which belonged to various serotypes (Ia, Ib, II–V), coded diverse Alp genes ( rib , alp 2, epsilon ), demonstrated two macrolide resistance phenotypes (cMLS B , iMLS B ), and belonged to different PFGE clusters (2, 3, 4, 5, 6, 12, 13, 29, 30). Procedures of protein preparation and analysis have been previously described ( Dobrut et al, 2018 ). They included cultivation in brain–heart infusion broth (Biocorp) at 37°C for 24 h. Afterward, the bacterial pellet whose final concentration equaled A600 nm = 1.0 was suspended in Tris–HCl (Merck) with the addition of sodium dodecyl sulfate in concentrations of 5–12.5% (Sigma-Aldrich, St. Louis, MI, United States) or directly in the electrophoresis buffer according to a slightly modified Heilmann’s procedure ( Heilmann et al, 1996 ).…”