Specific egg yolk antibodies (IgY) confer protection againstAcinetobacter baumanniiin a murine pneumonia model

Abstract

Aim: Acinetobacter baumannii, an increasingly serious health threat, is considered as one of the six most dangerous microbes of high mortality rate. However, treatment of its infections is difficult because of the lack of efficient antibiotic or commercial vaccines. Passive immunization through administration of specific antibodies such as IgY, could be an attractive practical solution. Methods and Results: In the current study, antigenicity of two recombinant outer membrane proteins (OmpA and Omp34) as well as inactivated whole cell of A. baumannii was assessed by ELISA. Moreover, prophylactic effects of specific IgY antibodies (avian antibody) raised against these antigens were evaluated in a murine pneumonia model. The specific IgY antibodies had various prophylactic effects in the pneumonia model. OmpA was the most potent antigen in terms of triggering antibody and conferring protection. While a synergic effect was observed in ELISA for antibodies raised against a combination of OmpA and Omp34 (which are known as Omp33-36 and Omp34 kDa), an antagonistic effect was unexpectedly seen in challenges. The reason for this phenomenon remains to be precisely addressed. Conclusion: All the specific IgY antibodies could protect mice against pneumonia caused by A. baumannii. Significance and Impact of the Study: The specific IgY antibodies could be employed as a pharmaceutical against pneumonia caused by A. baumannii. emergence of highly antibiotic-resistant strains including multidrug-resistant (MDR) and pan-drug-resistant strains (Wang et al. 2003;Dijkshoorn et al. 2007;Pach on and McConnell 2014). In spite of the increasing prevalence of MDR strains and their high mortality, an efficient antibiotic is not provided by the pharmaceutical industry for the treatment of its infections (Pach on and McConnell 2014). These implications highlight active and passive immunizations as cost-effective approaches to reduce the clinical and economic burden of infections caused by this notorious pathogen (Ahmad et al. 2016).

Protective potentials of a siderophore receptor against Acinetobacter baumannii infections

“…In this study, partial protection against A. baumannii lethal dose was achieved in passively immunized mice. Antisera against single recombinant proteins in the previous studies induced relative to complete protection [7-9, 15,40]. In the current study, the survival rate was higher against A. baumannii ATCC 19606 compared to clinical isolate, ABI022.…”

“…Therefore, further investigations are required to ensure the suggested reasons. Evaluation of specific avian antibodies (IgY) against OmpA, Omp34, and inactivated the whole cell in a pneumonia model showed that IgY-OmpA yielded the highest prophylactic effect [40] which is inconsistent with the results by Wang et al [51]. This contradiction can be due to a different type of capsule in studied clinical isolates.…”

“…Despite numerous studies devoted to A. baumannii, as a major threatening clinical factor, there are still quite a few unknown crucial aspects in developing new approaches to control the infections [1]. Using specific antibodies is considered as a strategy to prevent the A. baumannii infections for high risk persons [39,40]. Iron uptake system, as an important virulence factor of A. baumannii, has been studied in terms of functionality, pathogenicity, and immunogenicity [11, [41][42][43][44][45][46][47].…”

“…On the other hand, exposure of OMPs can be affected by capsule thickness [51]. However, studies continue on the surface bacterial structures as potential vaccine targets [40,52,53]. Therefore, further investigations are required to ensure the suggested reasons.…”

Peer Review #1 of "Codon optimization, expression in Escherichia coli, and immunogenicity analysis of deformed wing virus (DWV) structural protein (v0.1)"

“…However, research on therapeutic drugs against DWV is still rare. Egg yolk antibodies known as immunoglobulin Y (IgY) have been widely utilized in the prevention and control of epidemic diseases associated with Acinetobacter baumannii, Vibrio splendidus, the Dengue virus, noroviruses, rotaviruses, and duck adenovirus 3 (Fink et al, 2017;Ghosh et al, 2018;Jahangiri et al, 2019;Li et al, 2016;Yin et al, 2019). Moreover, Li sun reported that specific IgY could be obtained from hens immunized with an inactivated Chinese Sacbrood virus (CSBV) vaccine, which has the ability to neutralize CSBV (Sun et al, 2018).…”