[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fxLN3MUwXCdr5RPjwZYIDpOj8CHyjOmngWTgoKXPtZbg":3,"$fiIWdHDgHR0iWO9hhchKPinJ_6brWT-ZN1sRyvU64168":32,"$f3Ft0rKFJHppdzE-vuveecxx1BUcg9iOlMLtyzf_MJDg":47},[4,8,12,16,20,24,28],{"title":5,"slug":6,"path":7},"About Microbeonline.com","about-microbeonline-com","\u002Fabout-microbeonline-com\u002F",{"title":9,"slug":10,"path":11},"About Me","about-me","\u002Fabout-microbeonline-com\u002Fabout-me\u002F",{"title":13,"slug":14,"path":15},"Advertise with Us","advertise-us","\u002Fadvertise-us\u002F",{"title":17,"slug":18,"path":19},"Privacy Policy","privacy-policy","\u002Fprivacy-policy\u002F",{"title":21,"slug":22,"path":23},"Abbreviations","abbreviations","\u002Fabbreviations\u002F",{"title":25,"slug":26,"path":27},"Microbes","microbes","\u002Fmicrobes\u002F",{"title":29,"slug":30,"path":31},"Books","recommended-books","\u002Frecommended-books\u002F",{"type":33,"data":34},"blog",{"slug":35,"title":36,"description":36,"seoTitle":37,"seoDescription":37,"author":38,"createdDate":39,"lastUpdatedDate":40,"draft":41,"category":42,"image":37,"body":43,"faq":44,"tags":45,"related":46},"adjuvants-types-and-functions","Adjuvants: Types and Functions",null,"Acharya Tankeshwar","2022-05-02","2025-12-29",false,"immunology","Adjuvants are ingredients used in some vaccines to enhance the immunogenicity of antigens (immunogens). Adjuvants are used to boost the immune response when an antigen has low immunogenicity or when a small amount of antigen is available. For example, the antibody response of mice to immunization with bovine serum albumin (BSA) can be increased fivefold or more if the BSA is administered with an adjuvant.\n\n## Functions of Adjuvants\n\nThe precise mechanism of action of adjuvants is not entirely known but it is postulated that adjuvants exert one or more of the following effects to augment immune response;\n\n- Prolongs antigen persistence\n- Enhance co-stimulatory signals\n- Increases local inflammation and formation of granuloma\n- Stimulate nonspecific proliferation of lymphocytes\n- Stimulate Toll-like receptors on the surface of macrophages. This results in cytokine production (such as IL-12) that enhances the response of T cells and B cells to the immunogen.\n\n![Timeline of Adjuvant Used in Human Vaccines - Timeline of Adjuvant Used in Human Vaccines](https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FTimeline-of-Adjuvant-Used-in-Human-Vaccines.png)\n\u003Cfigcaption>Figure: Timeline of Adjuvant Used in Human Vaccines\u003C\u002Ffigcaption>\n\n## Types of Adjuvants\n\nSeveral different adjuvants are now available and have been used safely in vaccines. Some of the commonly used adjuvants are as follows;\n\n1. Aluminum\n2. Freund’s incomplete adjuvant\n3. Freund’s complete adjuvant\n4. *Mycobacterium tuberculosis*\n5. *Bordetella pertusis*\n6. Bacterial lipopolysaccharide (LPS)\n7. Synthetic polynucleotides (poly IC\u002Fpoly AU)\n8. Other adjuvants\n\nFor example, aluminum salts and Freund’s adjuvants stimulate a local chronic inflammatory response that attracts both phagocytes and lymphocytes. This infiltration of cells at the site of injection results in the formation of a dense, macrophage-rich mass of cells called a granuloma. The formation of granuloma enhances the activation of TH cells.\n\n### Aluminum\n\nAluminum salts such as aluminum potassium sulfate (alum), aluminum phosphate, aluminum hydroxide, and aluminum hydroxyphosphate sulfate (AAHS) are being used safely in vaccines since the 1930s to enhance the body’s immune response to vaccines. It is not used by the body and is gradually eliminated through the kidneys.\n\nAlum prolongs the persistence of antigen. When an antigen is mixed with alum, the salt precipitates the antigen. Injection of this alum precipitate results in a slower release of antigen from the injection site so that the effective time of exposure to the antigen increases from a few days without adjuvant to several weeks with adjuvant. The alum precipitate also increases the size of the antigen, thus increasing the probability of [phagocytosis.](\u002Fphagocytosis-mechanism-and-steps\u002F)\n\nAluminum adjuvants are used in various vaccines such as Hepatitis A (Havrix), Hepatitis B (Recombivax), HPV (Gardasil 9), [Japanese encephalitis](\u002Fjapanese-encephalitis-je-virus-structure-life-cycle-pathogenesis-diagnosis\u002F) (Ixiaro), and pneumococcal vaccine (Prevnar 13), etc.\n\n### Freund’s Incomplete Adjuvant\n\nIt contains antigen in an aqueous solution, mineral oil, and emulsifying agents such as mannide monooleate. Mannide monooleate disperses the oil into small droplets which surround the antigen. This causes a slow release of antigen from the site of injection.\n\n> Freund’s adjuvants are prohibited for human use.\n\n### Freund’s Complete Adjuvant\n\nFreund’s complete adjuvant, **formulated by Jules Freund**, contains heat-killed Mycobacteria as an additional ingredient to Freund’s incomplete adjuvant. Muramyl dipeptide which is a component of mycobacterial cell wall activates macrophages. Activated macrophages express higher levels of class II MHC molecules and the membrane molecules of the B7 family. These changes increase antigen presentation and enhancement of co-stimulatory signals respectively, making Freund’s complete adjuvant far more potent than the incomplete form.\n\n### Bacterial lipopolysaccharide (LPS)\n\n[Bacterial lipopolysaccharides](\u002Flipopolysaccharide-lps-of-gram-negative-bacteria-characteristics-and-functions\u002F) stimulate the nonspecific proliferation of lymphocytes. This increases the likelihood of antigen-induced clonal selection of lymphocytes.\n\n### Other adjuvants\n\nCervarix contains an adjuvant called AS04 (monophosphoryl lipid A + aluminum salt) that stimulates Toll-like receptors and thereby enhances antibody production.\n\nMF59 is an oil-in-water emulsion adjuvant and licensed for use in pandemic and seasonal influenza vaccines in many countries. A virosome (or IRIV, immunopotentiating reconstituted influenza virosome) is a type of “artificial virus” that can be used to deliver vaccine antigens directly into a host cell. Influenza virosomes have been used for more than 10 years in commercial vaccines.\n\n**References and further readings**\n\n1. [Cellular and Molecular Immunology, 9th Edition](https:\u002F\u002Famzn.to\u002F2Ofk9Rv)\n2. [Kuby Immunology, 8th Edition](https:\u002F\u002Famzn.to\u002F2TXGUOX)\n3. [Roitt’s Essential Immunology, 13th Edition](https:\u002F\u002Famzn.to\u002F2OdRNal)\n4. Image source: Reprinted from “Timeline of Adjuvant Used in Human Vaccines”, by BioRender.com (2022). Retrieved from \u003Chttps:\u002F\u002Fapp.biorender.com\u002Fbiorender-templates>",[],[],[],[48,54,61,66,70,74,79,84,88,92],{"slug":49,"name":38,"description":50,"image":51,"body":52,"postCount":53},"acharya-tankeshwar","Editor-in-chief","https:\u002F\u002Fassets.microbeonline.com\u002Fauthors\u002Ftankeshwar-acharya-author-microbeonline.jpg","***Tankeshwar Acharya, MSc (Medical Microbiology)***\n\n*Tankeshwar Acharya is an Assistant Professor in the Department of Microbiology at Patan Academy of Health Sciences (PAHS), Nepal, where he has been teaching and practicing clinical microbiology for over 14 years. He is the founder of Microbe Online, one of the leading free microbiology education resources on the web, covering bacteriology, mycology, parasitology, immunology, and clinical laboratory diagnostics written from direct experience in both the classroom and the diagnostic laboratory.*",433,{"slug":55,"name":56,"description":57,"image":58,"body":59,"postCount":60},"ashma-shrestha","Ashma Shrestha","SEO Copywriter and Science Communicator\nKathmandu, Nepal","https:\u002F\u002Fassets.microbeonline.com\u002Fauthors\u002Fashma-shrestha.png","Ashma Shrestha holds a Master of Science in Medical Microbiology from the Institute of Science and Technology (IOST), Tribhuvan University, Nepal, where she developed a strong foundation in virology, molecular biology, and diagnostic microbiology.\n\nShe now works as an SEO Copywriter at Resolution Digital, where she combines her scientific training with research-driven content strategy. She is certified in Google Analytics and Google Business Profile (GBP), and brings a data-informed approach to science communication writing content that is not only accurate but structured to reach and serve the students who need it most.\n\nAt microbeonline, Ashma contributes articles primarily in virology and molecular biology, areas she finds most compelling for their mechanistic depth and their growing clinical relevance. Her writing reflects the same standard the site is built on: factual rigor, clear explanation of the *why* behind microbiology concepts, and content that helps students move from memorization to genuine understanding.\n\nShe is passionate about making complex microbiological concepts accessible without sacrificing accuracy; a skill that sits at the intersection of her scientific training and her professional work in content and SEO.",81,{"slug":62,"name":63,"description":64,"image":37,"body":37,"postCount":65},"sushmita-baniya","Sushmita Baniya","Author \u002F Contributor",32,{"slug":67,"name":68,"description":64,"image":37,"body":37,"postCount":69},"samikshya-acharya","Samikshya Acharya",20,{"slug":71,"name":72,"description":64,"image":37,"body":37,"postCount":73},"alisha-tripathi","Alisha Tripathi",6,{"slug":75,"name":76,"description":77,"image":37,"body":37,"postCount":78},"aastha-shrestha","Aastha Shrestha"," Author \u002F Contributor",10,{"slug":80,"name":81,"description":82,"image":37,"body":37,"postCount":83},"guest-author","Guest Author","Guest Author \u002F Contributor",2,{"slug":85,"name":86,"description":64,"image":37,"body":37,"postCount":87},"srijana-khanal","Srijana Khanal",18,{"slug":89,"name":90,"description":82,"image":37,"body":37,"postCount":91},"dr-poonam-acharya","Dr. Poonam Acharya",1,{"slug":93,"name":94,"description":64,"image":37,"body":95,"postCount":96},"nisha-rijal","Nisha Rijal","**Nisha Rijal** is a microbiologist and quality assurance specialist. She served for nearly 12 years as a microbiologist at the National Public Health Laboratory (NPHL), Nepal's national reference laboratory, and continues to work as a consultant microbiologist in international public health organization. ",51]