Analyze Diet
Clinical and vaccine immunology : CVI2008; 16(2); 176-183; doi: 10.1128/CVI.00336-08

Foal monocyte-derived dendritic cells become activated upon Rhodococcus equi infection.

Abstract: Susceptibility of foals to Rhodococcus equi pneumonia is exclusive to the first few months of life. The objective of this study was to investigate the immediate immunologic response of foal and adult horse antigen-presenting cells (APCs) upon infection with R. equi. We measured the activation of the antigen-presenting major histocompatibility complex (MHC) class II molecule, costimulatory molecules CD40 and CD86, the cytokine interleukin-12 (IL-12), and the transcriptional factor interferon regulatory factor 1 (IRF-1) in monocyte-derived macrophages (mMOs) and dendritic cells (mDCs) of adult horses and foals of different ages (from birth to 3 months of age) infected with virulent R. equi or its avirulent, plasmid-cured derivative. Infection with virulent or avirulent R. equi induced (P Publication Date: 2008-12-24 PubMed ID: 19109450PubMed Central: PMC2643540DOI: 10.1128/CVI.00336-08Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This study looks at the immune response of foal and adult horse cells when infected with a bacterium known as Rhodococcus equi, which can cause pneumonia in young horses. The researchers found that while foal cells react to the infection, there seems to be a limitation to a specific aspect of this response, which could affect the efficient preparation of the cells in fighting infections at an early age.

Understanding the Study’s Objective

  • The primary aim of this research was to examine the immediate immune response of young and mature horse antigen-presenting cells (APCs), upon infection with a bacterium known as Rhodococcus equi.
  • APCs are critical components of the immune system that process and present antigens to T-cells, instigating an immune response.
  • Rhodococcus equi is an bacterium that commonly causes a severe type of pneumonia in foals (young horses) but is typically not harmful to adult horses, and the susceptibility of foals to this infection is limited to the first few months of their lives.

Research Methodology and Findings

  • The researchers investigated the activation of several key components of the immune response: the MHC class II molecule, CD40 and CD86 costimulatory molecules, the cytokine interleukin-12 (IL-12), and the transcriptional factor interferon regulatory factor 1 (IRF-1)in monocyte-derived macrophages (mMOs) and dendritic cells (mDCs).
  • They conducted their research on cells from adult horses and foals of different ages, from birth, up to 3 months, infected with virulent R. equi or its non-virulent, plasmid-cured derivative.
  • The results suggested that whether infected with a virulent or non-virulent version of R. equi, both foal and adult horse cells exhibited a response, as shown by the expression of IL-12p35 and IL-12p40 mRNAs.
  • However, the researchers found limitations to the MHC class II molecule expression, which they hypothesize may compromise the efficient preparation of naïve effector cells in early life, thus making them more susceptible to R. equi pneumonia.

Significance and Implications

  • The importance of this research lies in its contribution to our understanding of the immunological differences between foals and adult horses, particularly their respective responses to R. equi infection.
  • The limitations found in MHC class II molecule expression could potentially explain why foals are uniquely susceptible to R. equi pneumonia in the first few months of life.
  • The results may prove useful in the development of treatments or preventive measures to protect foals from R. equi pneumonia.

Cite This Article

APA
Flaminio MJ, Nydam DV, Marquis H, Matychak MB, Giguère S. (2008). Foal monocyte-derived dendritic cells become activated upon Rhodococcus equi infection. Clin Vaccine Immunol, 16(2), 176-183. https://doi.org/10.1128/CVI.00336-08

Publication

ISSN: 1556-679X
NlmUniqueID: 101252125
Country: United States
Language: English
Volume: 16
Issue: 2
Pages: 176-183

Researcher Affiliations

Flaminio, M Julia B F
  • Department of Clinical Sciences, Cornell University, Ithaca, New York 14853, USA. mbf6@cornell.edu
Nydam, Daryl V
    Marquis, Hélène
      Matychak, Mary Beth
        Giguère, Steeve

          MeSH Terms

          • Animals
          • Animals, Newborn
          • B7-2 Antigen / biosynthesis
          • CD40 Antigens / biosynthesis
          • Cells, Cultured
          • Dendritic Cells / immunology
          • Dendritic Cells / microbiology
          • Flow Cytometry
          • Gene Expression Profiling
          • Histocompatibility Antigens Class II / biosynthesis
          • Horses
          • Interferon Regulatory Factor-1 / biosynthesis
          • Interleukin-12 / biosynthesis
          • Reverse Transcriptase Polymerase Chain Reaction
          • Rhodococcus equi / immunology

          References

          This article includes 64 references
          1. Banchereau J, Steinman RM. Dendritic cells and the control of immunity.. Nature 1998 Mar 19;392(6673):245-52.
            pubmed: 9521319doi: 10.1038/32588google scholar: lookup
          2. Breathnach CC, Sturgill-Wright T, Stiltner JL, Adams AA, Lunn DP, Horohov DW. Foals are interferon gamma-deficient at birth.. Vet Immunol Immunopathol 2006 Aug 15;112(3-4):199-209.
            pubmed: 16621024doi: 10.1016/j.vetimm.2006.02.010google scholar: lookup
          3. Chaffin MK, Cohen ND, Martens RJ. Evaluation of equine breeding farm management and preventative health practices as risk factors for development of Rhodococcus equi pneumonia in foals.. J Am Vet Med Assoc 2003 Feb 15;222(4):476-85.
            pubmed: 12597421doi: 10.2460/javma.2003.222.476google scholar: lookup
          4. Chaffin MK, Cohen ND, Martens RJ, Edwards RF, Nevill M. Foal-related risk factors associated with development of Rhodococcus equi pneumonia on farms with endemic infection.. J Am Vet Med Assoc 2003 Dec 15;223(12):1791-9.
            pubmed: 14690209doi: 10.2460/javma.2003.223.1791google scholar: lookup
          5. Coccia EM. IFN regulation and functions in myeloid dendritic cells.. Cytokine Growth Factor Rev 2008 Feb;19(1):21-32.
            pubmed: 18054516doi: 10.1016/j.cytogfr.2007.10.005google scholar: lookup
          6. Cohen ND, O'Conor MS, Chaffin MK, Martens RJ. Farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals.. J Am Vet Med Assoc 2005 Feb 1;226(3):404-13.
            pubmed: 15702691doi: 10.2460/javma.2005.226.404google scholar: lookup
          7. Crow MK. Modification of accessory molecule signaling.. Springer Semin Immunopathol 2006 Jun;27(4):409-24.
            pubmed: 16738953doi: 10.1007/s00281-006-0018-3google scholar: lookup
          8. Darrah PA, Hondalus MK, Chen Q, Ischiropoulos H, Mosser DM. Cooperation between reactive oxygen and nitrogen intermediates in killing of Rhodococcus equi by activated macrophages.. Infect Immun 2000 Jun;68(6):3587-93.
          9. Darrah PA, Monaco MC, Jain S, Hondalus MK, Golenbock DT, Mosser DM. Innate immune responses to Rhodococcus equi.. J Immunol 2004 Aug 1;173(3):1914-24.
            pubmed: 15265925doi: 10.4049/jimmunol.173.3.1914google scholar: lookup
          10. Fernandez-Mora E, Polidori M, Lührmann A, Schaible UE, Haas A. Maturation of Rhodococcus equi-containing vacuoles is arrested after completion of the early endosome stage.. Traffic 2005 Aug;6(8):635-53.
          11. Flaminio MJ, Rush BR, Shuman W. Peripheral blood lymphocyte subpopulations and immunoglobulin concentrations in healthy foals and foals with Rhodococcus equi pneumonia.. J Vet Intern Med 1999 May-Jun;13(3):206-12.
          12. Flaminio MJ, Borges AS, Nydam DV, Horohov DW, Hecker R, Matychak MB. The effect of CpG-ODN on antigen presenting cells of the foal.. J Immune Based Ther Vaccines 2007 Jan 25;5:1.
            pmc: PMC1797044pubmed: 17254326doi: 10.1186/1476-8518-5-1google scholar: lookup
          13. Gabriele L, Ozato K. The role of the interferon regulatory factor (IRF) family in dendritic cell development and function.. Cytokine Growth Factor Rev 2007 Oct-Dec;18(5-6):503-10.
            pubmed: 17702640doi: 10.1016/j.cytogfr.2007.06.008google scholar: lookup
          14. Garton NJ, Gilleron M, Brando T, Dan HH, Giguère S, Puzo G, Prescott JF, Sutcliffe IC. A novel lipoarabinomannan from the equine pathogen Rhodococcus equi. Structure and effect on macrophage cytokine production.. J Biol Chem 2002 Aug 30;277(35):31722-33.
            pubmed: 12072437doi: 10.1074/jbc.m203008200google scholar: lookup
          15. Giacomini E, Iona E, Ferroni L, Miettinen M, Fattorini L, Orefici G, Julkunen I, Coccia EM. Infection of human macrophages and dendritic cells with Mycobacterium tuberculosis induces a differential cytokine gene expression that modulates T cell response.. J Immunol 2001 Jun 15;166(12):7033-41.
            pubmed: 11390447doi: 10.4049/jimmunol.166.12.7033google scholar: lookup
          16. Giguère S, Prescott JF. Clinical manifestations, diagnosis, treatment, and prevention of Rhodococcus equi infections in foals.. Vet Microbiol 1997 Jun 16;56(3-4):313-34.
            pubmed: 9226845doi: 10.1016/s0378-1135(97)00099-0google scholar: lookup
          17. Giguère S, Prescott JF. Cytokine induction in murine macrophages infected with virulent and avirulent Rhodococcus equi.. Infect Immun 1998 May;66(5):1848-54.
          18. Giguère S, Hondalus MK, Yager JA, Darrah P, Mosser DM, Prescott JF. Role of the 85-kilobase plasmid and plasmid-encoded virulence-associated protein A in intracellular survival and virulence of Rhodococcus equi.. Infect Immun 1999 Jul;67(7):3548-57.
          19. Giguère S, Wilkie BN, Prescott JF. Modulation of cytokine response of pneumonic foals by virulent Rhodococcus equi.. Infect Immun 1999 Oct;67(10):5041-7.
          20. Goriely S, Neurath MF, Goldman M. How microorganisms tip the balance between interleukin-12 family members.. Nat Rev Immunol 2008 Jan;8(1):81-6.
            pubmed: 18084185doi: 10.1038/nri2225google scholar: lookup
          21. Hietala SK, Ardans AA. Neutrophil phagocytic and serum opsonic response of the foal to Corynebacterium equi.. Vet Immunol Immunopathol 1987 Mar;14(3):279-94.
            pubmed: 3109114doi: 10.1016/0165-2427(87)90096-1google scholar: lookup
          22. Hines MT, Paasch KM, Alperin DC, Palmer GH, Westhoff NC, Hines SA. Immunity to Rhodococcus equi: antigen-specific recall responses in the lungs of adult horses.. Vet Immunol Immunopathol 2001 May 10;79(1-2):101-14.
            pubmed: 11356253doi: 10.1016/s0165-2427(01)00258-6google scholar: lookup
          23. Hines SA, Stone DM, Hines MT, Alperin DC, Knowles DP, Norton LK, Hamilton MJ, Davis WC, McGuire TC. Clearance of virulent but not avirulent Rhodococcus equi from the lungs of adult horses is associated with intracytoplasmic gamma interferon production by CD4+ and CD8+ T lymphocytes.. Clin Diagn Lab Immunol 2003 Mar;10(2):208-15.
          24. Honda K, Taniguchi T. IRFs: master regulators of signalling by Toll-like receptors and cytosolic pattern-recognition receptors.. Nat Rev Immunol 2006 Sep;6(9):644-58.
            pubmed: 16932750doi: 10.1038/nri1900google scholar: lookup
          25. Hondalus MK, Diamond MS, Rosenthal LA, Springer TA, Mosser DM. The intracellular bacterium Rhodococcus equi requires Mac-1 to bind to mammalian cells.. Infect Immun 1993 Jul;61(7):2919-29.
          26. Hondalus MK, Mosser DM. Survival and replication of Rhodococcus equi in macrophages.. Infect Immun 1994 Oct;62(10):4167-75.
          27. Horowitz ML, Cohen ND, Takai S, Becu T, Chaffin MK, Chu KK, Magdesian KG, Martens RJ. Application of Sartwell's model (lognormal distribution of incubation periods) to age at onset and age at death of foals with Rhodococcus equi pneumonia as evidence of perinatal infection.. J Vet Intern Med 2001 May-Jun;15(3):171-5.
          28. Jacks S, Giguère S, Prescott JF. In vivo expression of and cell-mediated immune responses to the plasmid-encoded virulence-associated proteins of Rhodococcus equi in foals.. Clin Vaccine Immunol 2007 Apr;14(4):369-74.
            pmc: PMC1865619pubmed: 17301216doi: 10.1128/cvi.00448-06google scholar: lookup
          29. Jacks S, Giguère S, Crawford PC, Castleman WL. Experimental infection of neonatal foals with Rhodococcus equi triggers adult-like gamma interferon induction.. Clin Vaccine Immunol 2007 Jun;14(6):669-77.
            pmc: PMC1951072pubmed: 17409222doi: 10.1128/cvi.00042-07google scholar: lookup
          30. Jain S, Bloom BR, Hondalus MK. Deletion of vapA encoding Virulence Associated Protein A attenuates the intracellular actinomycete Rhodococcus equi.. Mol Microbiol 2003 Oct;50(1):115-28.
          31. Jiao X, Lo-Man R, Guermonprez P, Fiette L, Dériaud E, Burgaud S, Gicquel B, Winter N, Leclerc C. Dendritic cells are host cells for mycobacteria in vivo that trigger innate and acquired immunity.. J Immunol 2002 Feb 1;168(3):1294-301.
            pubmed: 11801668doi: 10.4049/jimmunol.168.3.1294google scholar: lookup
          32. Kaisho T, Tanaka T. Turning NF-kappaB and IRFs on and off in DC.. Trends Immunol 2008 Jul;29(7):329-36.
            pubmed: 18534908doi: 10.1016/j.it.2008.03.005google scholar: lookup
          33. Kanaly ST, Hines SA, Palmer GH. Cytokine modulation alters pulmonary clearance of Rhodococcus equi and development of granulomatous pneumonia.. Infect Immun 1995 Aug;63(8):3037-41.
          34. Kanaly ST, Hines SA, Palmer GH. Transfer of a CD4+ Th1 cell line to nude mice effects clearance of Rhodococcus equi from the lung.. Infect Immun 1996 Apr;64(4):1126-32.
          35. Kawai T, Akira S. TLR signaling.. Cell Death Differ 2006 May;13(5):816-25.
            pubmed: 16410796doi: 10.1038/sj.cdd.4401850google scholar: lookup
          36. Lohoff M, Mak TW. Roles of interferon-regulatory factors in T-helper-cell differentiation.. Nat Rev Immunol 2005 Feb;5(2):125-35.
            pubmed: 15688040doi: 10.1038/nri1552google scholar: lookup
          37. MacMicking J, Xie QW, Nathan C. Nitric oxide and macrophage function.. Annu Rev Immunol 1997;15:323-50.
          38. McDyer JF, Li Z, John S, Yu X, Wu CY, Ragheb JA. IL-2 receptor blockade inhibits late, but not early, IFN-gamma and CD40 ligand expression in human T cells: disruption of both IL-12-dependent and -independent pathways of IFN-gamma production.. J Immunol 2002 Sep 1;169(5):2736-46.
            pubmed: 12193748doi: 10.4049/jimmunol.169.5.2736google scholar: lookup
          39. Meijer WG, Prescott JF. Rhodococcus equi.. Vet Res 2004 Jul-Aug;35(4):383-96.
            pubmed: 15236672doi: 10.1051/vetres:2004024google scholar: lookup
          40. Morton AC, Begg AP, Anderson GA, Takai S, Lämmler C, Browning GF. Epidemiology of Rhodococcus equi strains on Thoroughbred horse farms.. Appl Environ Microbiol 2001 May;67(5):2167-75.
          41. Mosser DM, Hondalus MK. Rhodococcus equi: an emerging opportunistic pathogen.. Trends Microbiol 1996 Jan;4(1):29-33.
            pubmed: 8824792doi: 10.1016/0966-842x(96)81502-2google scholar: lookup
          42. Oppmann B, Lesley R, Blom B, Timans JC, Xu Y, Hunte B, Vega F, Yu N, Wang J, Singh K, Zonin F, Vaisberg E, Churakova T, Liu M, Gorman D, Wagner J, Zurawski S, Liu Y, Abrams JS, Moore KW, Rennick D, de Waal-Malefyt R, Hannum C, Bazan JF, Kastelein RA. Novel p19 protein engages IL-12p40 to form a cytokine, IL-23, with biological activities similar as well as distinct from IL-12.. Immunity 2000 Nov;13(5):715-25.
            pubmed: 11114383doi: 10.1016/s1074-7613(00)00070-4google scholar: lookup
          43. Ozato K, Tsujimura H, Tamura T. Toll-like receptor signaling and regulation of cytokine gene expression in the immune system.. Biotechniques 2002 Oct;Suppl:66-8, 70, 72 passim.
            pubmed: 12395929
          44. Patton KM, McGuire TC, Hines MT, Mealey RH, Hines SA. Rhodococcus equi-specific cytotoxic T lymphocytes in immune horses and development in asymptomatic foals.. Infect Immun 2005 Apr;73(4):2083-93.
          45. Paulnock DM, Demick KP, Coller SP. Analysis of interferon-gamma-dependent and -independent pathways of macrophage activation.. J Leukoc Biol 2000 May;67(5):677-82.
            pubmed: 10811008doi: 10.1002/jlb.67.5.677google scholar: lookup
          46. Polidori M, Haas A. VapI, a new member of the Rhodococcus equi Vap family.. Antonie Van Leeuwenhoek 2006 Oct;90(3):299-304.
            pubmed: 16871422doi: 10.1007/s10482-006-9073-ygoogle scholar: lookup
          47. Puech V, Chami M, Lemassu A, Lanéelle MA, Schiffler B, Gounon P, Bayan N, Benz R, Daffé M. Structure of the cell envelope of corynebacteria: importance of the non-covalently bound lipids in the formation of the cell wall permeability barrier and fracture plane.. Microbiology (Reading) 2001 May;147(Pt 5):1365-1382.
            pubmed: 11320139doi: 10.1099/00221287-147-5-1365google scholar: lookup
          48. Raabe MR, Issel CJ, Montelaro RC. Equine monocyte-derived macrophage cultures and their applications for infectivity and neutralization studies of equine infectious anemia virus.. J Virol Methods 1998 Mar;71(1):87-104.
            pubmed: 9628225doi: 10.1016/s0166-0934(97)00204-8google scholar: lookup
          49. Rosner, B. A. 1986. Nonparametric methods, p. 278-293. In B. Rosner (ed.), Fundamentals of biostatistics, 4th edition. Duxbury Press (ITP), Belmont, CA.
          50. Sari MA, Moali C, Boucher JL, Jaouen M, Mansuy D. Detection of a nitric oxide synthase possibly involved in the regulation of the Rhodococcus sp R312 nitrile hydratase.. Biochem Biophys Res Commun 1998 Sep 18;250(2):364-8.
            pubmed: 9753635doi: 10.1006/bbrc.1998.9320google scholar: lookup
          51. Schuurhuis DH, Fu N, Ossendorp F, Melief CJ. Ins and outs of dendritic cells.. Int Arch Allergy Immunol 2006;140(1):53-72.
            pubmed: 16534219doi: 10.1159/000092002google scholar: lookup
          52. Sekizaki T, Takai S, Egawa Y, Ikeda T, Ito H, Tsubaki S. Sequence of the Rhodococcus equi gene encoding the virulence-associated 15-17-kDa antigens.. Gene 1995 Mar 21;155(1):135-6.
            pubmed: 7698659doi: 10.1016/0378-1119(95)00009-ugoogle scholar: lookup
          53. Tailleux L, Neyrolles O, Honoré-Bouakline S, Perret E, Sanchez F, Abastado JP, Lagrange PH, Gluckman JC, Rosenzwajg M, Herrmann JL. Constrained intracellular survival of Mycobacterium tuberculosis in human dendritic cells.. J Immunol 2003 Feb 15;170(4):1939-48.
            pubmed: 12574362doi: 10.4049/jimmunol.170.4.1939google scholar: lookup
          54. Tailor P, Tamura T, Ozato K. IRF family proteins and type I interferon induction in dendritic cells.. Cell Res 2006 Feb;16(2):134-40.
            pubmed: 16474425doi: 10.1038/sj.cr.7310018google scholar: lookup
          55. Takai S, Hines SA, Sekizaki T, Nicholson VM, Alperin DA, Osaki M, Takamatsu D, Nakamura M, Suzuki K, Ogino N, Kakuda T, Dan H, Prescott JF. DNA sequence and comparison of virulence plasmids from Rhodococcus equi ATCC 33701 and 103.. Infect Immun 2000 Dec;68(12):6840-7.
          56. Tamura T, Yanai H, Savitsky D, Taniguchi T. The IRF family transcription factors in immunity and oncogenesis.. Annu Rev Immunol 2008;26:535-84.
          57. Tan C, Prescott JF, Patterson MC, Nicholson VM. Molecular characterization of a lipid-modified virulence-associated protein of Rhodococcus equi and its potential in protective immunity.. Can J Vet Res 1995 Jan;59(1):51-9.
            pmc: PMC1263734pubmed: 7704843
          58. Tascon RE, Soares CS, Ragno S, Stavropoulos E, Hirst EM, Colston MJ. Mycobacterium tuberculosis-activated dendritic cells induce protective immunity in mice.. Immunology 2000 Mar;99(3):473-80.
          59. Toyooka K, Takai S, Kirikae T. Rhodococcus equi can survive a phagolysosomal environment in macrophages by suppressing acidification of the phagolysosome.. J Med Microbiol 2005 Nov;54(Pt 11):1007-1015.
            pubmed: 16192430doi: 10.1099/jmm.0.46086-0google scholar: lookup
          60. Traub-Dargatz JL, Salman MD, Voss JL. Medical problems of adult horses, as ranked by equine practitioners.. J Am Vet Med Assoc 1991 May 15;198(10):1745-7.
            pubmed: 2071472
          61. Trinchieri G, Pflanz S, Kastelein RA. The IL-12 family of heterodimeric cytokines: new players in the regulation of T cell responses.. Immunity 2003 Nov;19(5):641-4.
            pubmed: 14614851doi: 10.1016/s1074-7613(03)00296-6google scholar: lookup
          62. Uhl EW, Giguère S, Jack TJ, Hodge T. Increased pulmonary activation of nuclear factor-kappaB (NF-kappaB) in foals inoculated with Rhodococcus equi is associated with increased expression of inflammatory cytokines.. Vet Pathol 2002 Jan;39(1):132-6.
            pubmed: 12102205doi: 10.1354/vp.39-1-132google scholar: lookup
          63. Unutmaz D, Vilcek J. IRF1: a deus ex machina in TH1 differentiation.. Nat Immunol 2008 Jan;9(1):9-10.
            pubmed: 18087248doi: 10.1038/ni0108-9google scholar: lookup
          64. Zink MC, Yager JA, Prescott JF, Fernando MA. Electron microscopic investigation of intracellular events after ingestion of Rhodococcus equi by foal alveolar macrophages.. Vet Microbiol 1987 Aug;14(3):295-305.
            pubmed: 3672872doi: 10.1016/0378-1135(87)90117-9google scholar: lookup

          Citations

          This article has been cited 6 times.
          1. Bordin AI, Cohen ND, Giguère S, Bray JM, Berghaus LJ, Scott B, Johnson R, Hook M. Host-directed therapy in foals can enhance functional innate immunity and reduce severity of Rhodococcus equi pneumonia.. Sci Rep 2021 Jan 28;11(1):2483.
            doi: 10.1038/s41598-021-82049-ypubmed: 33510265google scholar: lookup
          2. Tallmadge RL, Wang M, Sun Q, Felippe MJB. Transcriptome analysis of immune genes in peripheral blood mononuclear cells of young foals and adult horses.. PLoS One 2018;13(9):e0202646.
            doi: 10.1371/journal.pone.0202646pubmed: 30183726google scholar: lookup
          3. Tallmadge RL, Miller SC, Parry SA, Felippe MJB. Antigen-specific immunoglobulin variable region sequencing measures humoral immune response to vaccination in the equine neonate.. PLoS One 2017;12(5):e0177831.
            doi: 10.1371/journal.pone.0177831pubmed: 28520789google scholar: lookup
          4. Kachroo P, Ivanov I, Seabury AG, Liu M, Chowdhary BP, Cohen ND. Age-related changes following in vitro stimulation with Rhodococcus equi of peripheral blood leukocytes from neonatal foals.. PLoS One 2013;8(5):e62879.
            doi: 10.1371/journal.pone.0062879pubmed: 23690962google scholar: lookup
          5. Ryan C, Giguère S. Equine neonates have attenuated humoral and cell-mediated immune responses to a killed adjuvanted vaccine compared to adult horses.. Clin Vaccine Immunol 2010 Dec;17(12):1896-902.
            doi: 10.1128/CVI.00328-10pubmed: 20943883google scholar: lookup
          6. Wagner B, Burton A, Ainsworth D. Interferon-gamma, interleukin-4 and interleukin-10 production by T helper cells reveals intact Th1 and regulatory TR1 cell activation and a delay of the Th2 cell response in equine neonates and foals.. Vet Res 2010 Jul-Aug;41(4):47.
            doi: 10.1051/vetres/2010019pubmed: 20374696google scholar: lookup