{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,22]],"date-time":"2026-07-22T10:18:05Z","timestamp":1784715485889,"version":"3.55.0"},"reference-count":44,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2025,2,6]],"date-time":"2025-02-06T00:00:00Z","timestamp":1738800000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"JSPS KAKENHI","award":["19K06474"],"award-info":[{"award-number":["19K06474"]}]},{"name":"JSPS KAKENHI","award":["24K12568"],"award-info":[{"award-number":["24K12568"]}]},{"name":"JSPS KAKENHI","award":["23K17435"],"award-info":[{"award-number":["23K17435"]}]},{"name":"JSPS KAKENHI","award":["21K18298"],"award-info":[{"award-number":["21K18298"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Complement factor B (CFB) is a crucial component for the activation of the alternative pathway due to the formation of the C3 convertase with C3b, which further produces C3b to enhance the overall complement activity. Although Cfb is expressed not only in the immune tissues, but also in the reproductive tract, the physiological role of the alternative complement pathway in reproduction remains unclear. In this study, we addressed this issue by producing Cfb-knockout (KO) mice and analyzing their phenotypes. Sperm function, number of ovulated oocytes, and litter size were normal in KO mice. In contrast, the diversity of microbiomes in the gut and vaginal tract significantly increased in KO mice. Some serine protease activity in the serum from KO mice was lower than that of wild-type mice. Since the serum from KO mice showed significantly lower activity of the alternative complement pathway, CFB was found to be essential for this pathway. Our results indicate that although the alternative pathway is dispensable for normal fertility and development, it maintains the gut and vaginal microbiomes by suppressing their diversity and activating the alternative complement pathway.<\/jats:p>","DOI":"10.3390\/ijms26031393","type":"journal-article","created":{"date-parts":[[2025,2,6]],"date-time":"2025-02-06T11:32:32Z","timestamp":1738841552000},"page":"1393","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Complement Factor B Deficiency Is Dispensable for Female Fertility but Affects Microbiome Diversity and Complement Activity"],"prefix":"10.3390","volume":"26","author":[{"given":"Manato","family":"Sunamoto","sequence":"first","affiliation":[{"name":"Laboratory of Regulatory Biology, Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Kawasaki 214-8571, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kazunori","family":"Morohoshi","sequence":"additional","affiliation":[{"name":"Laboratory of Regulatory Biology, Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Kawasaki 214-8571, Japan"},{"name":"Division of Biomedical Engineering, National Defense Medical College Research Institute, 3-2 Namiki, Tokorozawa 359-8513, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ban","family":"Sato","sequence":"additional","affiliation":[{"name":"Laboratory of Regulatory Biology, Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Kawasaki 214-8571, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ryo","family":"Mihashi","sequence":"additional","affiliation":[{"name":"Laboratory of Regulatory Biology, Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Kawasaki 214-8571, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4720-007X","authenticated-orcid":false,"given":"Masafumi","family":"Inui","sequence":"additional","affiliation":[{"name":"Laboratory of Animal Regeneration Systemology, Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Kawasaki 214-8571, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7560-316X","authenticated-orcid":false,"given":"Mitsutoshi","family":"Yamada","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8339-6738","authenticated-orcid":false,"given":"Kenji","family":"Miyado","sequence":"additional","affiliation":[{"name":"Department of Reproductive Biology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Natsuko","family":"Kawano","sequence":"additional","affiliation":[{"name":"Laboratory of Regulatory Biology, Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Kawasaki 214-8571, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1111\/imr.12474","article-title":"Evolution of the complement system: From defense of the single cell to guardian of the intravascular space","volume":"274","author":"Elvington","year":"2016","journal-title":"Immunol. 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