[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fxLN3MUwXCdr5RPjwZYIDpOj8CHyjOmngWTgoKXPtZbg":3,"$fF21cVWdElEc0-32cXxVuCCdlwZk_x3UFrald1zXza4s":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},"differences-between-primary-secondary-immune-response","Primary vs. Secondary Immune Response",null,"Nisha Rijal","2018-05-07","2025-12-29",false,"difference-between","The initial encounter of a naïve immune-competent lymphocyte with an antigen induces a\\*\\*primary immune response;\\*\\*a later contact of the host with the same antigen will induce a more rapid and heightened **secondary immune response.**\n\n![ - Differences in the Primary and Secondary Immune Response.Image source: Abbas et. al: Cellular and Molecular Immunology](https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FPrimary-and-Secondary-Immune-Response.png)Figure: Differences in the Primary and Secondary Immune Response.Image source: Abbas et. al: Cellular and Molecular Immunology\n\nThe amplified population of memory cells accounts for the rapidity and intensity distinguishing a secondary response from a primary one.\n\nWe apply the concept of **immune response** to produce needed immunity in a host through vaccination. Antigens administered in the body via vaccination imitate the infectious agent; thus body produces T-lymphocyte, B-lymphocyte, and antibodies against it. If a vaccinated person encounters infection later in life (by the same pathogen), the memory B cells and T cells fight off the infection rapidly and in heightened response, thus giving protection.\n\nIn some vaccines, the first dose (primary response) does not provide needed immunity, and that immunity may begin to wear off after a certain period. In such cases, we provide more shots and even booster doses to keep immunity at the needed level (i.e., to maintain the population of memory cells).\n\n#### Major characteristics\u002Fdifferences between primary and secondary immune responses are summarized in this table\n\n\u003Ctable style=\"min-width: 75px;\">\n\u003Ccolgroup>\u003Ccol style=\"min-width: 25px;\">\u003Ccol style=\"min-width: 25px;\">\u003Ccol style=\"min-width: 25px;\">\u003C\u002Fcolgroup>\u003Ctbody>\u003Ctr>\u003Cth colspan=\"1\" rowspan=\"1\">\u003Cp>\u003C\u002Fp>\u003Cp>\u003C\u002Fp>\u003C\u002Fth>\u003Cth colspan=\"1\" rowspan=\"1\">\u003Cp>Primary Immune Response\u003C\u002Fp>\u003C\u002Fth>\u003Cth colspan=\"1\" rowspan=\"1\">\u003Cp>Secondary Immune Response\u003C\u002Fp>\u003C\u002Fth>\u003C\u002Ftr>\u003Ctr>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Definition\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Immune response against primary antigenic challenge\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Immune response against subsequent antigenic challenge\u003C\u002Fp>\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Response\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Low, sluggish (appear late), and short-lived\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Prompt,  powerful, and prolonged (long-lasting)\u003C\u002Fp>\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Antibody producing cells\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Naïve B cells\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Memory B cells\u003C\u002Fp>\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Peak Response\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Smaller\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Larger\u003C\u002Fp>\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Antibody levels\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Antibody levels peak in the primary response at about day 14 and then begin to drop off as the plasma cells begin to die.\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Because there are many more memory cells than naïve B cells for the primary response, more plasma cells are generated in the secondary response, and antibody levels are 100 to 1000 fold higher.\u003C\u002Fp>\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Lag period\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>The lag period is longer (4-7 days) This lag is the time required for the activation of naive B cells by antigen and TH cells and the subsequent proliferation and differentiation of the activated B cells into plasma cells.\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>The lag period is absent or short (1-3 days) The secondary response reflects the activity of the clonally expanded population of memory B cells. These memory B cells respond to antigens more rapidly than naïve B cells.\u003C\u002Fp>\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Negative phase\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>No negative phase\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>A negative phase may occur\u003C\u002Fp>\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Antibody Isotype\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>The antibody is produced in low titer and is of IgM type. The disease diagnosis presence of IgM is suggestive of a recent primary infection.\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Antibody is produced in high titer and mainly IgG type (IgA or IgE in certain situations). In the diagnostics, the presence of IgG should be interpreted cautiously as it may be because of previous vaccination or subsequent sub-clinical infections (local cut-off titer or previous infections with the same agent).\u003C\u002Fp>\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Specificity of Antibody\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Antibodies are more specific but less avid\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Antibodies are less specific but more avid\u003C\u002Fp>\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Antibody Affinity\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Lower average affinity, more variable\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Higher average affinity (affinity maturation)\u003C\u002Fp>\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Induced by\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>All immunogens (Both T-dependent and T-independent antigens are processed by primary immune response)\u003C\u002Fp>\u003C\u002Ftd>\u003Ctd colspan=\"1\" rowspan=\"1\">\u003Cp>Only protein antigens (Only T dependent antigens are processed)\u003C\u002Fp>\u003C\u002Ftd>\u003C\u002Ftr>\u003C\u002Ftbody>\n\u003C\u002Ftable>\n\n**References**\n\n1. [Kuby Immunology, 8th Edition](https:\u002F\u002Famzn.to\u002F2TXGUOX)\n2. [Roitt’s Essential Immunology, 13th Edition](https:\u002F\u002Famzn.to\u002F2OdRNal)",[],[],[],[48,55,62,67,71,75,80,85,89,93],{"slug":49,"name":50,"description":51,"image":52,"body":53,"postCount":54},"acharya-tankeshwar","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":56,"name":57,"description":58,"image":59,"body":60,"postCount":61},"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":63,"name":64,"description":65,"image":37,"body":37,"postCount":66},"sushmita-baniya","Sushmita Baniya","Author \u002F Contributor",32,{"slug":68,"name":69,"description":65,"image":37,"body":37,"postCount":70},"samikshya-acharya","Samikshya Acharya",20,{"slug":72,"name":73,"description":65,"image":37,"body":37,"postCount":74},"alisha-tripathi","Alisha Tripathi",6,{"slug":76,"name":77,"description":78,"image":37,"body":37,"postCount":79},"aastha-shrestha","Aastha Shrestha"," Author \u002F Contributor",10,{"slug":81,"name":82,"description":83,"image":37,"body":37,"postCount":84},"guest-author","Guest Author","Guest Author \u002F Contributor",2,{"slug":86,"name":87,"description":65,"image":37,"body":37,"postCount":88},"srijana-khanal","Srijana Khanal",18,{"slug":90,"name":91,"description":83,"image":37,"body":37,"postCount":92},"dr-poonam-acharya","Dr. Poonam Acharya",1,{"slug":94,"name":38,"description":65,"image":37,"body":95,"postCount":96},"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]