- EGFR Signaling Pathway
- TGF-beta Signaling
- Canonical Wnt Signaling
- non-Canonical Wnt Signaling
- Notch Signaling
- p53 Pathway
- NF-kB Pathway
- Cytokine Signaling
The adaptive immune or specific immune response consists of antibody responses and cell-mediated responses, which are carried out by different lymphocyte cells, B cells and T cells, respectively. B Cells are the major cells involved in the creation of antibodies that circulate in blood plasma and lymph, where they bind specifically to the foreign antigens. Cell-mediated immunity does not involve antibodies but rather involves the activation of macrophages, natural killer cells (NK), antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. A key feature of the adaptive immune system is memory, the development of immunological memory, in which each pathogen is “remembered” by a signature antibody.
Adaptive Immunity Related Products Index
Quality proteins, antibodies, ELISA pair sets, cDNA clones for adaptive immunity research.
Adaptive Immune System
The immune system recognizes and kills pathogens and tumor cells to protect the host. The immune system is composed of two major subdivisions, the innate (non-specific) immune system and the adaptive immune system, which is also called specific immune system or acquired immune system.
A key feature of the adaptive immune system is memory, the development of immunological memory, in which each pathogen is “remembered” by a signature antibody. Part of activated B cells and T cells can develop to memory cells. Memory cells remain ready to respond rapidly and efficiently to a subsequent encounter with a pathogen. This so-called secondary response is often stronger than the primary response to infection.
Adaptive Immunity Definition
Adaptive immunity is an important part of the immune system. It is protection from an infectious disease agent that is mediated by B- and T- lymphocytes following exposure to specific antigen, and characterized by immunological memory. Adaptive immunity can result from either previous infection with that agent or vaccination (immunity, active), or transfer of antibody or lymphocytes from an immune donor (immunization, passive).
Adaptive Immune Response
The adaptive immune response consists of antibody responses and cell-mediated responses, which are carried out by different lymphocyte cells, B cells and T cells, respectively. B Cells are the major cells involved in the creation of antibodies that circulate in blood plasma and lymph, where they bind specifically to the foreign antigens. Binding of antibody inactivates viruses and microbial toxins by blocking their ability to bind to receptors on host cells. Antibodies, also known as immunoglobulins, are large Y-shaped proteins, which are typically composed of two large heavy chains and two small light chains. In mammals there are five types of antibody: IgA, IgD, IgE, IgG, and IgM, differing in biological properties, each has evolved to handle different kinds of antigens. The antibody responses are also called humoral immunity. Cell-mediated immunity does not involve antibodies but rather involves the activation of macrophages, natural killer cells (NK), antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.
Vaccines may contain pathogen-associated molecular patterns (PAMPs) or may induce the local release of damage-associated molecular patterns (DAMPs). These PAMPs and DAMPs are detected directly by pattern-recognition receptors (PRRs) expressed by dendritic cells (DCs), leading to DC activation, maturation and migration to the lymph nodes. Alternatively, PRR-mediated recognition of PAMPs and DAMPs by bystander cells may induce the release of tissue-derived factors, such as cytokines, that may cooperate in the activation and orientation of the DC response. In the lymph nodes, the activated DCs (APC) may present antigens to T cells, provide them with co-stimulatory signals and stimulate their differentiation by providing a favourable cytokine milieu. Some cytokines — such as interleukin-4 (IL-4) and type I interferons (IFNs) — may be provided by bystander cells. Depending on the cytokine milieu, CD4+ T cells may differentiate into various T helper (TH) cell subtypes. TH cells may also acquire a T follicular helper (TFH) cell phenotype and help in the activation of cognate B cells, thereby promoting the entry of these B cells into the plasma cell pathway or the germinal centre pathway. In addition, the cytokine expression profile of TFH cells can dictate B cell isotype switching. Depending on the balance between activating cytokines (and most often with the help of TH1 cell-derived IL-2), activated CD8+ T cells differentiate into effector and memory CD8+ T cells. The induction of adaptive immune response is showed in the following figure. APC, antigen presenting cell; TCR, T cell receptor.
Innate and Adaptive Immunity
Until recently innate immunity was largely ignored as the adaptive immunity was thought to play a key role in the immune response. Now it became clear that innate immunity has an important role as the first line of defense against pathogens as well as in development of an adaptive immune response. The polarization of immune response largely depends on the initial signals that are brought by innate immunity. There are some essential signals, required to induce T- and B-cell responses. Innate immune signals modulate the quantity and the quality of adaptive immune response and are required to initiate an effective immune response, that mainly depends on the nature of the pathogen. There are two separated ways of antigen processing, which enable the immune system to appropriately respond against extracellular and intracellular pathogens, respectively.
Very simplified, we can say, that the result (polarization) of immune response depends on which player of innate branch of immune response (e.g., dendritic cell) recognized invading pathogen, how the peptides derived from antigenic components were presented (MHC I or MHC II molecules) and which immunomodulatory molecules were produced (e.g. IL-12). Therefore, cooperation between initial innate and subsequent adaptive response is needed for effective functioning of the immune system and immune response.
Adaptive Immunity Related Studies
- Christophe J, et al. (2012) Nucleic acid sensing at the interface between innate and adaptive immunity in vaccination. Nature Reviews Immunology. 12, 479-491.
- Siffrin V, et al. (2007) New insights into adaptive immunity in chronic neuroinflammation. Adv Immunol. 96:1-40.
- Yamamoto H, et al. (2008) Anti-HIV adaptive immunity: determinants for viral persistence. Rev Med Virol. 18(5):293-303.
- Fatourou EM, et al. (2009) Adaptive immunity in hepatocellular carcinoma: prognostic and therapeutic implications. Expert Rev Anticancer Ther. 9(10):1499-510.
- Andersson J, et al. (2010) Adaptive immunity and atherosclerosis. Clin Immunol. 134(1):33-46.