Developing an anti-Campylobacter jejunivaccine

Identification and evaluation of protection effect of B-cell immunodominant epitopes of campylobacter jejuni PEB1

To provide detail data for Campylobacter jejuni (C.jejuni) vaccine research, this study performed epitope prediction analysis technology to screen the B cell immunodominant epitopes of C. jejuni adhesion protein PEB1 and evaluated the immunoprotective effect. The overlapping peptides were synthesized and B-cell immunodominant epitopes of PEB1 were identified by ELISA. BALB/c mice were immunized with the immunodominant epitopes of PEB1 conjugated with KLH plus CFA/IFA. The titers for immunodominant peptide antiserum against PEB1 were detected by ELISA. The bacterial colonization and the relative expression level of TNF-α were analyzed after the mice challenged with C. jejuni 11,168. The function of antibody induced by immunodominant PEB1 epitopes were performed by opsonophagocytic killing. The results showed that PEB1_55-72aa, PEB1_97-114aa, PEB1_211-228aa were the immunodominant peptides and could induce strong B cell mediated humoral immunity response. Antiserum from the immunodominant peptides group significantly enhanced opsonize phagocytosis than CFA/IFA group (P<0.01). Both the bacterial burdens and the TNF-α expression level in the immunodominant peptides groups were significantly lower than those in the control group (P<0.01). Moreover, the immune protective effect of the three immunodominant peptides depended on the B cell immunity response in vivo study. In conclusion, three specific B cell immunodominant epitopes with good immunogenicity and immunoprotection efficacy were successfully identified, indicating that could be used in the anti- C. jejuni vaccine research and development.

Characterization of bacterial antimicrobial peptides active against Campylobacter jejuni

Campylobacter jejuni is one of the major causes of food poisoning, often resulting from the consumption of improperly cooked poultry products. The emergence of C. jejuni strains resistant to conventional antibiotics necessitates the evaluation of other possible treatments or preventative measures to minimize the impact and prevalence of infections. Antimicrobial peptides produced by bacteria have begun to emerge as a potential means of decreasing the levels of C. jejuni in poultry, thereby limiting Campylobacter contamination in associated food products. A number of bacteriocins produced by Gram-positive bacteria have unexpectedly been described as having antimicrobial activity against the Gram-negative C. jejuni. Additionally, some nonribosomal lipopeptides produced by Bacillus and Paenibacillus spp. show efficacy against this pathogen. This review will describe the bacterial antimicrobial peptides reported to be active against C. jejuni, with an emphasis on the characterization of their primary structures. However, for many of these peptides, little is known about their amino acid sequences and structures. Furthermore, there are unusual inconsistencies associated with the reported amino acid sequences for several of the more well-studied bacteriocins. Clarifying the chemical nature of these promising antimicrobial peptides is necessary before their potential utility for livestock protection from C. jejuni can be fully explored. Once these peptides are better characterized, they may prove to be strong candidates for minimizing the impact of Campylobacter on human health.

Peptide sharing between Bordetella pertussis proteome and human sudden death proteins: a hypothesis for a causal link

AIM

To explore the molecular basis of the relationship between Bordetella pertussis infection and sudden death.

METHODS

B. pertussis proteins were analyzed for amino acid sequence identity to a set of 67 human proteins that, when altered, have been associated with sudden death.

RESULTS

More than 82,000 pentapeptides are shared between B. pertussis proteins and sudden death-associated antigens.

CONCLUSION

Results suggest that a possible link between B. pertussis infection and sudden death might be represented by potential immunological cross-reactions occurring between B. pertussis proteins and human proteins associated to sudden death.

Evidence for a vast peptide overlap between West Nile virus and human proteomes

The primary amino acid sequence of West Nile virus (WNV) polyprotein, GenBank accession number M12294, was analyzed by computional biology. WNV is a mosquito-borne neurotropic flavivirus that has emerged globally as a significant cause of viral encephalitis in humans. Using pentapeptides as scanning units and the perfect peptide match program from PIR International Protein Sequence Database, we compared the WNV polyprotein and the human proteome. WNV polyprotein showed significant sequence similarities to a number of human proteins. Several of these proteins are involved in embryogenesis, neurite outgrowth, cortical neuron branching, formation of mature synapses, semaphorin interactions, and voltage dependent L-type calcium channel subunits. The biocomputional study suggest that common amino acid segments might represent a potential platform for further studies on the neurological pathophysiology of WNV infections.

Homology, similarity, and identity in peptide epitope immunodefinition

The tendency to use the terms homology, similarity, and identity interchangeably persists in comparative biology. When translated to immunology, overlapping the concepts of homology, similarity, and identity complicates the exact definition of the self-nonself dichotomy and, in particular, affects immunopeptidomics, an emerging field aimed at cataloging and distinguishing immunoreactive peptide epitopes from silent nonreactive amino acid sequences. The definition of similar/dissimilar peptides in immunology is discussed with special attention to the analysis of immunological (dis)similarity between two or more protein sequences that equates to measuring sequence similarity with the use of a proper measurement unit such as a length determinant.