Opsonization but not pretreatment of equine macrophages with hyperimmune plasma nonspecifically enhances phagocytosis and intracellular killing of Rhodococcus equi
Abstract Background Evidence regarding the efficacy of equine hyperimmune plasma to prevent pneumonia in foals caused by Rhodococcus equi is limited and conflicting. Hypothesis Opsonization with R. equi‐specific hyperimmune plasma (HIP) will significantly increase phagocytosis and decrease intracell...
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| Format: | Article |
| Language: | English |
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Wiley
2021-01-01
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| Series: | Journal of Veterinary Internal Medicine |
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| Online Access: | https://doi.org/10.1111/jvim.16002 |
| _version_ | 1828142103396352000 |
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| author | Aja B. Harvey Angela I. Bordin Joana N. Rocha Jocelyn M. Bray Noah D. Cohen |
| author_facet | Aja B. Harvey Angela I. Bordin Joana N. Rocha Jocelyn M. Bray Noah D. Cohen |
| author_sort | Aja B. Harvey |
| collection | DOAJ |
| description | Abstract Background Evidence regarding the efficacy of equine hyperimmune plasma to prevent pneumonia in foals caused by Rhodococcus equi is limited and conflicting. Hypothesis Opsonization with R. equi‐specific hyperimmune plasma (HIP) will significantly increase phagocytosis and decrease intracellular replication of R. equi by alveolar macrophages (AMs) compared to normal plasma (NP). Animals Fifteen adult Quarter Horses were used to collect bronchoalveolar lavage cells. Methods In the first experiment, AMs from 9 horses were pretreated (incubated) with either HIP, NP, or media only (control) and then infected with nonopsonized R. equi. In a second experiment, AMs from 6 horses were infected with R. equi either opsonized with HIP or opsonized with NP. For both experiments, AMs were lysed at 0 and 48 hours and the number of viable R. equi quantified by culture were compared among groups using linear mixed‐effects modeling with significance set at P < .05. Results Opsonization with either HIP or NP increased phagocytosis by AMs (P < .0001) and decreased intracellular survival of organisms in AMs (P < .0001). Pretreating AMs with either HIP or NP without opsonizing R. equi had no effects on phagocytosis or intracellular replication. Conclusions and Clinical Importance Opsonizing R. equi with either NP or HIP decreases intracellular survival of organisms in AMs, but the effect does not appear to be enhanced by using HIP. Mechanisms other than effects on AMs must explain any clinical benefits of using HIP over NP to decrease the incidence of R. equi pneumonia in foals. |
| first_indexed | 2024-04-11T19:36:17Z |
| format | Article |
| id | doaj.art-75f67f1debf24733834eb2f6856ef17d |
| institution | Directory Open Access Journal |
| issn | 0891-6640 1939-1676 |
| language | English |
| last_indexed | 2024-04-11T19:36:17Z |
| publishDate | 2021-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Journal of Veterinary Internal Medicine |
| spelling | doaj.art-75f67f1debf24733834eb2f6856ef17d2022-12-22T04:06:51ZengWileyJournal of Veterinary Internal Medicine0891-66401939-16762021-01-0135159059610.1111/jvim.16002Opsonization but not pretreatment of equine macrophages with hyperimmune plasma nonspecifically enhances phagocytosis and intracellular killing of Rhodococcus equiAja B. Harvey0Angela I. Bordin1Joana N. Rocha2Jocelyn M. Bray3Noah D. Cohen4Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University College Station Texas USADepartment of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University College Station Texas USADepartment of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University College Station Texas USADepartment of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University College Station Texas USADepartment of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University College Station Texas USAAbstract Background Evidence regarding the efficacy of equine hyperimmune plasma to prevent pneumonia in foals caused by Rhodococcus equi is limited and conflicting. Hypothesis Opsonization with R. equi‐specific hyperimmune plasma (HIP) will significantly increase phagocytosis and decrease intracellular replication of R. equi by alveolar macrophages (AMs) compared to normal plasma (NP). Animals Fifteen adult Quarter Horses were used to collect bronchoalveolar lavage cells. Methods In the first experiment, AMs from 9 horses were pretreated (incubated) with either HIP, NP, or media only (control) and then infected with nonopsonized R. equi. In a second experiment, AMs from 6 horses were infected with R. equi either opsonized with HIP or opsonized with NP. For both experiments, AMs were lysed at 0 and 48 hours and the number of viable R. equi quantified by culture were compared among groups using linear mixed‐effects modeling with significance set at P < .05. Results Opsonization with either HIP or NP increased phagocytosis by AMs (P < .0001) and decreased intracellular survival of organisms in AMs (P < .0001). Pretreating AMs with either HIP or NP without opsonizing R. equi had no effects on phagocytosis or intracellular replication. Conclusions and Clinical Importance Opsonizing R. equi with either NP or HIP decreases intracellular survival of organisms in AMs, but the effect does not appear to be enhanced by using HIP. Mechanisms other than effects on AMs must explain any clinical benefits of using HIP over NP to decrease the incidence of R. equi pneumonia in foals.https://doi.org/10.1111/jvim.16002alveolar macrophagesbacteriafoalsin vitro killing capacityintracellular survivalpneumonia |
| spellingShingle | Aja B. Harvey Angela I. Bordin Joana N. Rocha Jocelyn M. Bray Noah D. Cohen Opsonization but not pretreatment of equine macrophages with hyperimmune plasma nonspecifically enhances phagocytosis and intracellular killing of Rhodococcus equi Journal of Veterinary Internal Medicine alveolar macrophages bacteria foals in vitro killing capacity intracellular survival pneumonia |
| title | Opsonization but not pretreatment of equine macrophages with hyperimmune plasma nonspecifically enhances phagocytosis and intracellular killing of Rhodococcus equi |
| title_full | Opsonization but not pretreatment of equine macrophages with hyperimmune plasma nonspecifically enhances phagocytosis and intracellular killing of Rhodococcus equi |
| title_fullStr | Opsonization but not pretreatment of equine macrophages with hyperimmune plasma nonspecifically enhances phagocytosis and intracellular killing of Rhodococcus equi |
| title_full_unstemmed | Opsonization but not pretreatment of equine macrophages with hyperimmune plasma nonspecifically enhances phagocytosis and intracellular killing of Rhodococcus equi |
| title_short | Opsonization but not pretreatment of equine macrophages with hyperimmune plasma nonspecifically enhances phagocytosis and intracellular killing of Rhodococcus equi |
| title_sort | opsonization but not pretreatment of equine macrophages with hyperimmune plasma nonspecifically enhances phagocytosis and intracellular killing of rhodococcus equi |
| topic | alveolar macrophages bacteria foals in vitro killing capacity intracellular survival pneumonia |
| url | https://doi.org/10.1111/jvim.16002 |
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