{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,5]],"date-time":"2026-09-05T01:31:00Z","timestamp":1788571860676,"version":"build-2803163510"},"reference-count":51,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T00:00:00Z","timestamp":1782345600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Nexmos, Inc."}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antioxidants"],"abstract":"<jats:p>Natural killer (NK) cells are crucial components of innate immunity and rapidly eliminate abnormal cells through ligand\u2013receptor signaling without prior sensitization. Vitamin C is known to enhance NK cell function; however, its susceptibility to oxidation may limit its efficacy in NK cell activation. This study evaluated the efficacy of Aptamin C, a stabilized conjugate of vitamin C and an aptamer, in enhancing NK cell activation. In the in vivo randomized placebo-controlled study, 120 participants were randomized to receive either Aptamin C or placebo, and 109 participants were included in the final analysis. Participants received Aptamin C at a dose of 36.057 mg\/day or placebo for 4 weeks. The results showed significant increases in NK cell cytotoxicity after 2 and 4 weeks in the Aptamin C group. Additionally, serum levels of cytokines and cytotoxic granules associated with NK cell activity peaked 4 weeks after Aptamin C intake. Subgroup analysis showed that the enhancing effect of Aptamin C on NK cell activity was mainly observed in participants older than 40 years, whereas no significant effects were detected in participants aged &lt;40 years. In the in vitro study, NK-92 cells treated with Aptamin C were compared with NK-92 cells treated with vitamin C. Aptamin C treatment enhanced proliferation, survival, cytotoxicity, and cytotoxic granule production in NK-92 cells compared with vitamin C treatment. These findings indicate that Aptamin C may effectively promote NK cell activation, particularly in middle-aged and older adults, and suggest its potential as an immunomodulatory supplement for supporting NK cell function.<\/jats:p>","DOI":"10.3390\/antiox15070796","type":"journal-article","created":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T05:52:11Z","timestamp":1782453131000},"page":"796","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Effect of Aptamin C on NK Cell Activity and Cytotoxicity: A Randomized Placebo-Controlled Trial and In Vitro Comparison with Vitamin C"],"prefix":"10.3390","volume":"15","author":[{"given":"Hyovin","family":"Ahn","sequence":"first","affiliation":[{"name":"Laboratory of Vitamin C and Antioxidant Immunology, Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea"},{"name":"Institute of Allergy and Clinical Immunology, Medical Research Center, Seoul National University, Seoul 08826, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"June","family":"Lee","sequence":"additional","affiliation":[{"name":"Nexmos, Inc., Yongin-si 16827, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jeong-Ho","family":"Park","sequence":"additional","affiliation":[{"name":"Nexmos, Inc., Yongin-si 16827, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jae Sang","family":"Barn","sequence":"additional","affiliation":[{"name":"BABOBAGI Plastic Surgery, 517 Nonhyeon-ro, Gangnam-gu, Seoul 06129, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yejin","family":"Kim","sequence":"additional","affiliation":[{"name":"Laboratory of Vitamin C and Antioxidant Immunology, Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea"},{"name":"Institute of Allergy and Clinical Immunology, Medical Research Center, Seoul National University, Seoul 08826, Republic of Korea"},{"name":"Department of Research and Development, N Therapeutics Co., Ltd., Seoul 08813, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7675-9134","authenticated-orcid":false,"given":"Jae Seung","family":"Kang","sequence":"additional","affiliation":[{"name":"Laboratory of Vitamin C and Antioxidant Immunology, Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea"},{"name":"Institute of Allergy and Clinical Immunology, Medical Research Center, Seoul National University, Seoul 08826, Republic of Korea"},{"name":"Department of Research and Development, N Therapeutics Co., Ltd., Seoul 08813, Republic of Korea"},{"name":"Artificial Intelligence Institute, Seoul National University, Seoul 08826, Republic of Korea"},{"name":"Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1038\/35095564","article-title":"Natural killer cells, viruses and cancer","volume":"1","author":"Cerwenka","year":"2001","journal-title":"Nat. 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