{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T05:00:24Z","timestamp":1781067624623,"version":"3.54.1"},"reference-count":36,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T00:00:00Z","timestamp":1781049600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Immunocastration through vaccination against gonadotropin-releasing hormone (GnRH) represents a humane alternative to surgical castration in animal production. However, oral delivery of protein antigens remains challenging due to gastrointestinal degradation and poor mucosal immunogenicity. Polysaccharide microparticles (PSMs), particularly alginate-chitosan systems, offer protection against gastric degradation and enhanced mucosal uptake.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>To evaluate whether alginate-chitosan microparticles entrapping a recombinant GnRH-fusion protein (GF45) can elicit an immunocastrating response in male rats after oral administration.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>GF45, a 45 kDa fusion peptide containing four tandem GnRH repeats fused to Rickettsia heat-shock protein fragments, was expressed in E. coli BL21(DE3) and purified under denaturing conditions followed by refolding. Microparticles were prepared by ionic gelation achieving 64% encapsulation efficiency. Male Sprague-Dawley rats (4 weeks) received oral prime-boost immunizations (weeks 4 and 7) with 200 \u00b5g GF45 in microparticles (n = 10). Controls included empty microparticles (NC, n = 10) and subcutaneous GF45 + Freund\u2019s adjuvant (PC, n = 10). Serum testosterone and anti-GF45 IgG were monitored until week 16 via ELISA. Testes were weighed, volumetrically measured by Archimedes\u2019 principle, and histologically examined using Johnsen\u2019s scoring system.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Oral GF45 reduced circulating testosterone by 95% (0.7 \u00b1 0.3 vs 14.2 \u00b1 1.8 ng dL\n                      <jats:sup>-1<\/jats:sup>\n                      in NC; p &amp;lt; 0.0001) and induced anti-GF45 antibodies reaching 88.8% of the injectable response (titres log\n                      <jats:sub>10<\/jats:sub>\n                      4.1 \u00b1 0.3 vs 4.4 \u00b1 0.2; p = 0.08). Seroconversion began at week 6 post-prime, reaching 100% by week 16. Testis weight decreased by 52% and volume by 75% (both p &amp;lt; 0.01), accompanied by marked seminiferous-tubule atrophy (diameter reduced from 286 \u00b1 9 \u00b5m to 124 \u00b1 8 \u00b5m) and reduced Johnsen scores (3.2 \u00b1 0.4 vs 9.1 \u00b1 0.2; p &amp;lt; 0.001). Empty microparticles produced no effects.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Alginate-chitosan microparticles provide a practical, needle-free platform for oral immunocastration via induction of anti-GnRH autoimmunity. This polysaccharide-based system represents a versatile oral antigen carrier with potential applications in veterinary medicine and livestock production.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fimmu.2026.1843125","type":"journal-article","created":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T04:31:50Z","timestamp":1781065910000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Polysaccharide microparticles as an oral vaccine platform: proof-of-concept in male rats using a GnRH-targeting fusion antigen"],"prefix":"10.3389","volume":"17","author":[{"given":"Maximiliano","family":"Wilda","sequence":"first","affiliation":[{"name":"Centro de Virolog\u00eda Humana y Animal (CEVHAN) - CONICET-UAI","place":["Ciudad Aut\u00f3noma de Buenos Aires, Argentina"]},{"name":"C\u00e1tedra de Gen\u00e9tica Molecular, Facultad de Farmacia y Bioqu\u00edmica, Universidad de Buenos Aires","place":["Ciudad Aut\u00f3noma de Buenos Aires, Argentina"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria Victoria","family":"Rocca","sequence":"additional","affiliation":[{"name":"Centro de Virolog\u00eda Humana y Animal (CEVHAN) - CONICET-UAI","place":["Ciudad Aut\u00f3noma de Buenos Aires, Argentina"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. 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