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Liu L, Cai P, Gu W, Duan X, Gao S, Ma X, Ma Y, Ma S, Li G, Wang X, Cai K, Wang Y, Cai T, Zhao H. Evaluation of vaccine candidates against Rhodococcus equi in BALB/c mice infection model: cellular and humoral immune responses. BMC Microbiol 2024; 24:249. [PMID: 38977999 PMCID: PMC11229254 DOI: 10.1186/s12866-024-03408-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 07/02/2024] [Indexed: 07/10/2024] Open
Abstract
Rhodococcus equi (R. equi) is a zoonotic opportunistic pathogen that mainly causes fatal lung and extrapulmonary abscesses in foals and immunocompromised individuals. To date, no commercial vaccine against R. equi exists. We previously screened all potential vaccine candidates from the complete genome of R. equi using a reverse vaccinology approach. Five of these candidates, namely ABC transporter substrate-binding protein (ABC transporter), penicillin-binding protein 2 (PBD2), NlpC/P60 family protein (NlpC/P60), esterase family protein (Esterase), and M23 family metallopeptidase (M23) were selected for the evaluation of immunogenicity and immunoprotective effects in BALB/c mice model challenged with R. equi. The results showed that all five vaccine candidate-immunized mice experienced a significant increase in spleen antigen-specific IFN-γ- and TNF-α-positive CD4 + and CD8 + T lymphocytes and generated robust Th1- and Th2-type immune responses and antibody responses. Two weeks after the R. equi challenge, immunization with the five vaccine candidates reduced the bacterial load in the lungs and improved the pathological damage to the lungs and livers compared with those in the control group. NlpC/P60, Esterase, and M23 were more effective than the ABC transporter and PBD2 in inducing protective immunity against R. equi challenge in mice. In addition, these vaccine candidates have the potential to induce T lymphocyte memory immune responses in mice. In summary, these antigens are effective candidates for the development of protective vaccines against R. equi. The R. equi antigen library has been expanded and provides new ideas for the development of multivalent vaccines.
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Affiliation(s)
- Lu Liu
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
- Xinjiang Key Laboratory of New Drug Study and Creation for Herbivorous Animal, Urumqi, China
| | - Peng Cai
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Weifang Gu
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Xingxun Duan
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Shiwen Gao
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Xuelian Ma
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
- Xinjiang Key Laboratory of New Drug Study and Creation for Herbivorous Animal, Urumqi, China
| | - Yuhui Ma
- Zhaosu Xiyu Horse Industry Co., Ltd., Yining, China
| | - Siyuan Ma
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Guoqing Li
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Xiangyu Wang
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Kuojun Cai
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Yanfeng Wang
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Tao Cai
- Xinjiang Agricultural Vocational Technical College, Changji, China
| | - Hongqiong Zhao
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China.
- Xinjiang Key Laboratory of New Drug Study and Creation for Herbivorous Animal, Urumqi, China.
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Bordin AI, Huber L, Sanz M, Cohen N. Rhodococcus equi Foal Pneumonia: Update on Epidemiology, Immunity, Treatment, and Prevention. Equine Vet J 2022; 54:481-494. [PMID: 35188690 DOI: 10.1111/evj.13567] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/03/2022] [Accepted: 02/17/2022] [Indexed: 11/25/2022]
Abstract
Pneumonia in foals caused by the bacterium Rhodococcus equi has a worldwide distribution and is a common cause of disease and death for foals. The purpose of this narrative review is to summarise recent developments pertaining to the epidemiology, immune responses, treatment, and prevention of rhodococcal pneumonia of foals. Screening tests have been used to implement earlier detection and treatment of foals with presumed subclinical R. equi pneumonia to reduce mortality and severity of disease. Unfortunately, this practice has been linked to the emergence of antimicrobial resistant R. equi in North America. Correlates of protective immunity for R. equi infections of foals remain elusive, but recent evidence indicates that innate immune responses are important both for mediating killing and orchestrating adaptive immune responses. A macrolide antimicrobial in combination with rifampin remains the recommended treatment for foals with R. equi pneumonia. Great need exists to identify which antimicrobial combination is most effective for treating foals with R. equi pneumonia and to limit emergence of antimicrobial-resistant strains. In the absence of an effective vaccine against R. equi, passive immunisation remains the only commercially-available method for effectively reducing the incidence of R. equi pneumonia. Because passive immunisation is expensive, labour-intensive, and carries risks for foals, great need exists to develop alternative approaches for passive and active immunisation.
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Affiliation(s)
- Angela I Bordin
- Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4475, USA
| | - Laura Huber
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, 36849, USA
| | - Macarena Sanz
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, 99164-6610, USA
| | - Noah Cohen
- Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4475, USA
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