{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T22:32:56Z","timestamp":1782945176891,"version":"3.54.5"},"reference-count":41,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2017,7,26]],"date-time":"2017-07-26T00:00:00Z","timestamp":1501027200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Marine Drugs"],"abstract":"<jats:p>Chitosan oligosaccharides (COS), the degraded products of chitosan, have been demonstrated to have versatile biological functions. In primary studies, it has displayed significant adjuvant effects when mixed with other vaccines. In this study, chitosan oligosaccharides with different deacetylation degrees were prepared and conjugated to porcine circovirus type 2 (PCV2) subunit vaccine to enhance its immunogenicity. The vaccine conjugates were designed by the covalent linkage of COSs to PCV2 molecules and administered to BALB\/c mice three times at two-week intervals. The results indicate that, as compared to the PCV2 group, COS\u2013PCV2 conjugates remarkably enhanced both humoral and cellular immunity against PCV2 by promoting lymphocyte proliferation and initiating a mixed T-helper 1 (Th1)\/T-helper 2 (Th2) response, including raised levels of PCV2-specific antibodies and an increased production of inflammatory cytokines. Noticeably, with the increasing deacetylation degree, the stronger immune responses to PCV2 were observed in the groups with COS-PCV2 vaccination. In comparison with NACOS (chitin oligosaccharides)\u2013PCV2 and LCOS (chitosan oligosaccharides with low deacetylation degree)\u2013PCV2, HCOS (chitosan oligosaccharides with high deacetylation degree)\u2013PCV2 showed the highest adjuvant effect, even comparable to that of PCV2\/ISA206 (a commercialized adjuvant) group. In summary, COS conjugation might be a viable strategy to enhance the immune response to PCV2 subunit vaccine, and the adjuvant effect was positively correlated with the deacetylation degree of COS.<\/jats:p>","DOI":"10.3390\/md15080236","type":"journal-article","created":{"date-parts":[[2017,7,26]],"date-time":"2017-07-26T11:45:01Z","timestamp":1501069501000},"page":"236","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":19,"title":["The Positive Correlation of the Enhanced Immune Response to PCV2 Subunit Vaccine by Conjugation of Chitosan Oligosaccharide with the Deacetylation Degree"],"prefix":"10.3390","volume":"15","author":[{"given":"Guiqiang","family":"Zhang","sequence":"first","affiliation":[{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Key Laboratory of Biopharmaceutical Production &amp; Formulation Engineering, PLA and State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gong","family":"Cheng","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biopharmaceutical Production &amp; Formulation Engineering, PLA and State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peiyuan","family":"Jia","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biopharmaceutical Production &amp; Formulation Engineering, PLA and State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Siming","family":"Jiao","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biopharmaceutical Production &amp; Formulation Engineering, PLA and State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cui","family":"Feng","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biopharmaceutical Production &amp; Formulation Engineering, PLA and State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tao","family":"Hu","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biopharmaceutical Production &amp; Formulation Engineering, PLA and State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongtao","family":"Liu","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biopharmaceutical Production &amp; Formulation Engineering, PLA and State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuguang","family":"Du","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biopharmaceutical Production &amp; Formulation Engineering, PLA and State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2017,7,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1016\/j.foodhyd.2015.05.023","article-title":"Biological effects of chitosan and its derivatives","volume":"51","author":"Ngo","year":"2015","journal-title":"Food Hydrocoll."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1482","DOI":"10.3390\/md8051482","article-title":"Production of chitooligosaccharides and their potential applications in medicine","volume":"8","author":"Aam","year":"2010","journal-title":"Mar. 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