A proteome-wide screen of Campylobacter jejuni using protein microarrays identifies novel and conformational antigens

Abstract

Campylobacter jejuni (C. jejuni) is a foodborne intestinal pathogen and major cause of gastroenteritis worldwide. C. jejuni proteins that are immunogenic have been sought for their potential use in the development of biomarkers, diagnostic assays, or subunit vaccines for humans or livestock. To identify new immunogenic C. jejuni proteins, we used a native protein microarray approach. A protein chip, with over 1400 individually purified GST-tagged C. jejuni proteins, representing over 86% of the proteome, was constructed to screen for antibody titers present in test sera raised against whole C. jejuni cells. Dual detection of GST signals was incorporated as a way of normalizing the variation of protein concentrations contributing to the antibody staining intensities. We detected strong signals to 102 C. jejuni antigens. In addition to antigens recognized by antiserum raised against C. jejuni, parallel experiments were conducted to identify antigens cross-reactive to antiserum raised against various serotypes of E. coli or Salmonella or to healthy human sera. This led to the identification of 34 antigens specifically recognized by the C. jejuni antiserum, only four of which were previously known. The chip approach also allowed identification of conformational antigens. We demonstrate in the case of Cj1621 that antigen signals are lost to denaturing conditions commonly used in other approaches to identify immunogens. Antigens identified in this study include those possessing sequence features indicative of cell surface localization, as well as those that do not. Together, our results indicate that the unbiased chip-based screen can help reveal the full repertoire of host antibodies against microbial proteomes.

Ehrlichia chaffeensis and E. canis hypothetical protein immunoanalysis reveals small secreted immunodominant proteins and conformation-dependent antibody epitopes

“…A few conformation-dependent epitopes have also been described in bacterial proteins, such as E. ch. TRP32, Yersinia pseudotuberculosis OmpF porin, and Campylobacter jejuni membrane protein Cj1621 6,42,46 . These proteins have been demonstrated to play an important role in pathogen infection and eliciting host antibody response.…”

“…However, our recent studies have revealed the functional aspects of TRPs, and it is now established that they are secreted effectors that interact with an array of host proteins and have various distinct functions during infection 38 – 41 . Hypothetical proteins have also been shown to be predominant immunoreactive proteins in other intracellular pathogens, suggesting that many antigenic and potentially protective proteins have unknown function 24 , 42 . Therefore, based on previous empirical data we considered hypothetical proteins to be higher priority candidates and the focus of this study.…”

Update and review of control options for Campylobacter in broilers at primary production

“…Six of them were tested on broilers in experimental husbandries and four candidates showed Campylobacter load decreases in caeca by 2-4 logs CFU/g correlated with the induction of specific humoral responses (Meunier et al, 2017). Liu et al (2019) used a native protein microarray approach and identified 30 new immunogenic C. jejuni proteins but no information was provided about in vivo testing. Vandeputte et al (2019) reported that in ovo-vaccinated birds using vaccines based on maternal antibodies were not protected with the treated birds showing similar caecal C. Jejuni concentrations to the control birds.…”

“…Liu et al. () used a native protein microarray approach and identified 30 new immunogenic C. jejuni proteins but no information was provided about in vivo testing. Vandeputte et al.…”

Development of a Trivalent Construct Omp18/AhpC/FlgH Multi Epitope Peptide Vaccine Against Campylobacter jejuni

“…Passive immunization could lower the possibility of colonization and transmission of C. jejuni in broiler chickens ( Hermans et al, 2014 ). So far, there has been no vaccine approved by any global regulatory authority targeted at preventing Campylobacter-associated diseases ( Liu et al, 2019 ). Nevertheless, several efforts are underway to design vaccines against C. jejuni , including the conventional approach of adopting the live attenuated or heat-killed whole cells as potential vaccines.…”