Abstract
Innate immunity was for a long time considered to be non-specific because the major function of this system is to digest pathogens and present antigens to the cells involved in acquired immunity. However, recent studies have shown that innate immunity is not non-specific, but is instead sufficiently specific to discriminate self from pathogens through evolutionarily conserved receptors, designated Toll-like receptors (TLRs). Indeed, innate immunity has a crucial role in early host defence against invading pathogens. Furthermore, TLRs were found to act as adjuvant receptors that create a bridge between innate and adaptive immunity, and to have important roles in the induction of adaptive immunity. This paradigm shift is now changing our thinking on the pathogenesis and treatment of infectious, immune and allergic diseases, as well as cancers. Besides TLRs, recent findings have revealed the presence of a cytosolic detector system for invading pathogens. I will review the mechanisms of pathogen recognition by TLRs and cytoplasmic receptors, and then discuss the roles of these receptors in the development of adaptive immunity in response to viral infection.
Highlights
Innate immunity was for a long time considered to be non-specific because the major function of this system is to digest pathogens and present antigens to the cells involved in acquired immunity
Paul Ehrlich proposed his famous side-chain theory of immunity. He believed that toxic substances produced by bacteria bind to cells through side-chain molecular structures expressed on the cell surface, thereby causing disease, and that the body produces abundant side-chains in the blood to react with the specific bacterial toxins, preventing the toxins from reacting with the side-chains of cells
Humoral immunity is involved in the eradication of microbes present in the blood or fluid by generating antibodies, which are produced by B cells
Summary
Vaccination was started by Edward Jenner based on the common observation that milkmaids who had suffered from cowpox were protected against smallpox: he used a cowpox vaccine to immunize humans against smallpox. At the end of the nineteenth century, Shibasaburo Kitasato and Emil von Behring demonstrated the value of antitoxins in preventing disease by producing passive immunity to tetanus in animals that received graded injections of blood serum from another animal infected with the disease This represented the first discovery of antibodies. Paul Ehrlich proposed his famous side-chain theory of immunity He believed that toxic substances produced by bacteria bind to cells through side-chain molecular structures expressed on the cell surface, thereby causing disease, and that the body produces abundant side-chains (antibodies) in the blood to react with the specific bacterial toxins, preventing the toxins from reacting with the side-chains of cells. While humoral immunity research subsequently made remarkable progress, innate immunity was, until recently, regarded as an ancient and non-specific immunity that functions in the lower animal kingdom
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Schedule a callMore From: Philosophical Transactions of the Royal Society B: Biological Sciences
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