{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,7,24]],"date-time":"2026-07-24T22:39:43Z","timestamp":1784932783770,"version":"3.55.0"},"posted":{"date-parts":[[2025,3,17]]},"group-title":"Microbiology","reference-count":59,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2025,3,17]],"date-time":"2025-03-17T00:00:00Z","timestamp":1742169600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2025,3,17]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                <jats:p>\n                  Acute virulence in\n                  <jats:italic>Toxoplasma gondii<\/jats:italic>\n                  is linked to an excessive proinflammatory cytokine cascade during laboratory murine infection. Previous work showed that\n                  <jats:italic>T. gondii<\/jats:italic>\n                  secretes a pore forming protein, PLP1, that is required for efficient cytolytic egress from host cells. Deletion of the\n                  <jats:italic>PLP1<\/jats:italic>\n                  gene results in defective egress from infected culture cells and a marked reduction in parasite virulence. The goal of the present study was to gain insight into the nature of the attenuated virulence observed in\n                  <jats:italic>PLP1<\/jats:italic>\n                  knockout compared to wild type (WT) RH parasites. Using\n                  <jats:italic>in vivo<\/jats:italic>\n                  bioluminescence imaging, we show that parasites lacking PLP1 establish an acute infection and disseminate throughout the infected mice. Histological tissue analysis indicates that parasites cause severe pathology, even in the absence of PLP1. However, mice infected with\n                  <jats:italic>\u0394plp1<\/jats:italic>\n                  parasites evoke a protective inflammatory response, demonstrated by mouse survival and control of infection. Flow cytometric analysis was used to determine cellular changes occurring during both WT and \u0394\n                  <jats:italic>plp1<\/jats:italic>\n                  parasite infection. Parasite control in the\n                  <jats:italic>\u0394plp1<\/jats:italic>\n                  infection was associated with earlier activation of myeloid cells and a moderate neutrophil response that, by comparison, becomes the dominant infiltrating cell type of WT infection. Positive disease outcome during\n                  <jats:italic>\u0394plp1<\/jats:italic>\n                  parasite infection is also associated with regulated induction of proinflammatory cytokines, including IFN-\u03b3 and TNF-\u03b1, and an earlier IL-10 regulatory response that is dysregulated during WT infection. Together these findings suggest a key role for\n                  <jats:italic>Toxoplasma<\/jats:italic>\n                  PLP1 in promoting a lethal inflammatory immune response during acute infection with a virulent strain of the parasite.\n                <\/jats:p>\n                <jats:sec>\n                  <jats:title>Author Summary<\/jats:title>\n                  <jats:p>\n                    Pore-forming proteins are virulence determinants expressed by multiple different pathogens, with varied roles including cellular invasion and escape, immune cell destruction, and the hijack of host cell defenses. The pathogen,\n                    <jats:italic>Toxoplasma gondii<\/jats:italic>\n                    , expresses a pore-forming protein PLP1, that is required for cell lysis and acute virulence in mice. Here, we investigate the potential mechanisms by which this pore-forming protein promotes parasite virulence; from parasite replication and dissemination to immunologic outcomes after infection.\n                    <jats:italic>In vivo<\/jats:italic>\n                    infections demonstrate that parasites replicate, disseminate, and stimulate a protective immune response when PLP1 is not expressed. We show that PLP1 expression induces a parasite driven dysregulation of cell populations and cytokine\/chemokine responses, resulting in cytokine release syndrome. In a broader context,\n                    <jats:italic>Toxoplasma\u2019s<\/jats:italic>\n                    PLP1 is comparable to other pathogen pore-forming proteins that function as virulence determinants by their ability to alter host immune responses.\n                  <\/jats:p>\n                <\/jats:sec>","DOI":"10.1101\/2025.03.17.643671","type":"posted-content","created":{"date-parts":[[2025,3,19]],"date-time":"2025-03-19T17:16:26Z","timestamp":1742404586000},"source":"Crossref","is-referenced-by-count":2,"title":["<i>Toxoplasma<\/i>\n                  induced cytokine release syndrome is critically dependent on the expression of pore-forming Perforin-Like Protein-1"],"prefix":"10.64898","author":[{"given":"Beth","family":"Gregg","sequence":"first","affiliation":[{"name":"Molecular Parasitology Section, Laboratory of Parasitic Diseases, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alfredo J.","family":"Guerra","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephen A.","family":"Raverty","sequence":"additional","affiliation":[{"name":"Animal Health Centre, Ministry of Agriculture, Abbotsford, British Columbia, V3G 2M3, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aline","family":"Sardinha-Silva","sequence":"additional","affiliation":[{"name":"Molecular Parasitology Section, Laboratory of Parasitic Diseases, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0089-1096","authenticated-orcid":false,"given":"Bjorn F.C.","family":"Kafsack","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tracey L.","family":"Schultz","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephen J.","family":"Gurczynski","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bethany B.","family":"Moore","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vern B.","family":"Carruthers","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3465-3782","authenticated-orcid":false,"given":"Michael E.","family":"Grigg","sequence":"additional","affiliation":[{"name":"Molecular Parasitology Section, Laboratory of Parasitic Diseases, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026041120510527000_2025.03.17.643671v1.1","doi-asserted-by":"publisher","DOI":"10.1016\/0169-4758(88)90018-x"},{"key":"2026041120510527000_2025.03.17.643671v1.2","doi-asserted-by":"publisher","DOI":"10.1128\/CMR.11.4.569"},{"key":"2026041120510527000_2025.03.17.643671v1.3","doi-asserted-by":"publisher","DOI":"10.1016\/j.pt.2017.04.001"},{"key":"2026041120510527000_2025.03.17.643671v1.4","doi-asserted-by":"publisher","DOI":"10.1128\/CMR.11.2.267"},{"key":"2026041120510527000_2025.03.17.643671v1.5","doi-asserted-by":"publisher","DOI":"10.1093\/clinids\/15.2.211"},{"key":"2026041120510527000_2025.03.17.643671v1.6","doi-asserted-by":"publisher","DOI":"10.1093\/clind\/24.4.676"},{"key":"2026041120510527000_2025.03.17.643671v1.7","doi-asserted-by":"publisher","DOI":"10.1093\/jpids\/piu077"},{"key":"2026041120510527000_2025.03.17.643671v1.8","doi-asserted-by":"publisher","DOI":"10.1038\/359082a0"},{"key":"2026041120510527000_2025.03.17.643671v1.9","doi-asserted-by":"publisher","DOI":"10.1093\/infdis\/172.6.1561"},{"key":"2026041120510527000_2025.03.17.643671v1.10","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1203190109"},{"key":"2026041120510527000_2025.03.17.643671v1.11","doi-asserted-by":"publisher","DOI":"10.1017\/S0031182013001844"},{"key":"2026041120510527000_2025.03.17.643671v1.12","doi-asserted-by":"publisher","DOI":"10.1016\/j.meegid.2017.06.002"},{"key":"2026041120510527000_2025.03.17.643671v1.13","doi-asserted-by":"publisher","DOI":"10.1016\/j.meegid.2011.12.010"},{"key":"2026041120510527000_2025.03.17.643671v1.14","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijpara.2003.12.008"},{"key":"2026041120510527000_2025.03.17.643671v1.15","doi-asserted-by":"publisher","DOI":"10.1128\/Iai.64.12.5193-5198.1996"},{"key":"2026041120510527000_2025.03.17.643671v1.16","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.167.2.902"},{"key":"2026041120510527000_2025.03.17.643671v1.17","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.167.8.4574"},{"issue":"6","key":"2026041120510527000_2025.03.17.643671v1.18","first-page":"827","article-title":"Interferon-gamma receptor-deficiency renders mice highly susceptible to toxoplasmosis by decreased macrophage activation","volume":"75","year":"1996","journal-title":"Lab Invest"},{"key":"2026041120510527000_2025.03.17.643671v1.19","doi-asserted-by":"publisher","DOI":"10.1126\/science.3128869"},{"key":"2026041120510527000_2025.03.17.643671v1.20","doi-asserted-by":"publisher","DOI":"10.1016\/S0171-2985(99)80064-3"},{"key":"2026041120510527000_2025.03.17.643671v1.21","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.90.13.6115"},{"key":"2026041120510527000_2025.03.17.643671v1.22","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.153.6.2533"},{"issue":"1","key":"2026041120510527000_2025.03.17.643671v1.23","first-page":"16","article-title":"Studies on the role of interleukin-12 in acute murine toxoplasmosis","volume":"84","year":"1995","journal-title":"Immunology"},{"key":"2026041120510527000_2025.03.17.643671v1.24","doi-asserted-by":"publisher","DOI":"10.1128\/iai.60.5.1979-1983.1992"},{"key":"2026041120510527000_2025.03.17.643671v1.25","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.160.7.3427"},{"key":"2026041120510527000_2025.03.17.643671v1.26","doi-asserted-by":"publisher","DOI":"10.1371\/journal.ppat.1007476"},{"key":"2026041120510527000_2025.03.17.643671v1.27","doi-asserted-by":"publisher","DOI":"10.1126\/science.1165740"},{"key":"2026041120510527000_2025.03.17.643671v1.28","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M113.450932"},{"key":"2026041120510527000_2025.03.17.643671v1.29","doi-asserted-by":"publisher","DOI":"10.1371\/journal.ppat.1004488"},{"key":"2026041120510527000_2025.03.17.643671v1.30","doi-asserted-by":"publisher","DOI":"10.1007\/s00018-020-03450-w"},{"key":"2026041120510527000_2025.03.17.643671v1.31","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.00333-12"},{"key":"2026041120510527000_2025.03.17.643671v1.32","doi-asserted-by":"publisher","DOI":"10.1016\/j.immuni.2009.06.023"},{"key":"2026041120510527000_2025.03.17.643671v1.33","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0915000107"},{"key":"2026041120510527000_2025.03.17.643671v1.34","doi-asserted-by":"publisher","DOI":"10.3389\/fimmu.2015.00225"},{"key":"2026041120510527000_2025.03.17.643671v1.35","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.00472-09"},{"key":"2026041120510527000_2025.03.17.643671v1.36","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.0903450"},{"key":"2026041120510527000_2025.03.17.643671v1.37","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.163.4.2081"},{"key":"2026041120510527000_2025.03.17.643671v1.38","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.165.8.4515"},{"key":"2026041120510527000_2025.03.17.643671v1.39","doi-asserted-by":"publisher","DOI":"10.1016\/j.immuni.2021.06.006"},{"key":"2026041120510527000_2025.03.17.643671v1.40","doi-asserted-by":"publisher","DOI":"10.1016\/j.smim.2021.101516"},{"key":"2026041120510527000_2025.03.17.643671v1.41","doi-asserted-by":"publisher","DOI":"10.1084\/jem.184.2.597"},{"key":"2026041120510527000_2025.03.17.643671v1.42","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-3024.1999.00237.x"},{"key":"2026041120510527000_2025.03.17.643671v1.43","doi-asserted-by":"publisher","DOI":"10.2147\/ITT.S202015"},{"key":"2026041120510527000_2025.03.17.643671v1.44","doi-asserted-by":"publisher","DOI":"10.1016\/j.cell.2016.08.019"},{"key":"2026041120510527000_2025.03.17.643671v1.45","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.73.10.6199-6209.2005"},{"key":"2026041120510527000_2025.03.17.643671v1.46","doi-asserted-by":"publisher","DOI":"10.1128\/MMBR.00052-12"},{"key":"2026041120510527000_2025.03.17.643671v1.47","doi-asserted-by":"publisher","DOI":"10.1038\/nature04515"},{"key":"2026041120510527000_2025.03.17.643671v1.48","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.181.12.8485"},{"key":"2026041120510527000_2025.03.17.643671v1.49","doi-asserted-by":"publisher","DOI":"10.1111\/j.1462-5822.2006.00735.x"},{"key":"2026041120510527000_2025.03.17.643671v1.50","doi-asserted-by":"publisher","DOI":"10.1111\/cmi.12808"},{"key":"2026041120510527000_2025.03.17.643671v1.51","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2958.2011.07942.x"},{"key":"2026041120510527000_2025.03.17.643671v1.52","doi-asserted-by":"publisher","DOI":"10.1111\/j.1462-5822.2008.01245.x"},{"key":"2026041120510527000_2025.03.17.643671v1.53","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.167.11.6503"},{"key":"2026041120510527000_2025.03.17.643671v1.54","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0006387"},{"key":"2026041120510527000_2025.03.17.643671v1.55","doi-asserted-by":"publisher","DOI":"10.3389\/fimmu.2013.00018"},{"key":"2026041120510527000_2025.03.17.643671v1.56","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.165.5.2783"},{"key":"2026041120510527000_2025.03.17.643671v1.57","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMra2026131"},{"key":"2026041120510527000_2025.03.17.643671v1.58","doi-asserted-by":"publisher","DOI":"10.7554\/eLife.68312"},{"key":"2026041120510527000_2025.03.17.643671v1.59","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.73.2.695-702.2005"}],"container-title":[],"original-title":[],"link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1101\/2025.03.17.643671","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,12]],"date-time":"2026-04-12T03:51:12Z","timestamp":1775965872000},"score":1,"resource":{"primary":{"URL":"http:\/\/biorxiv.org\/lookup\/doi\/10.1101\/2025.03.17.643671"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,3,17]]},"references-count":59,"URL":"https:\/\/doi.org\/10.1101\/2025.03.17.643671","relation":{},"subject":[],"published":{"date-parts":[[2025,3,17]]},"subtype":"preprint"}}