prostate-specific antigen

(noun)

PSA, is a member of the kallikrein-related peptidase family and is secreted by the epithelial cells of the prostate gland. It is often elevated in the presence of prostate cancer or other prostate disorders.

Related Terms

  • prostatitis
  • adenocarcinoma

Examples of prostate-specific antigen in the following topics:

  • Prostate Disorders

    • The common prostate disorders are: prostatitis, benign prostatic hyperplasia, high-grade intraepithelial neoplasia, and prostate cancer.
    • The most common prostate disorders are: prostatitis, benign prostatic hyperplasia, high-grade intraepithelial neoplasia, and prostate cancer.
    • For men under 50, the most common prostate problem is prostatitis.
    • Prostatitis is inflammation of the prostate gland.
    • The presence of prostate cancer may be indicated by symptoms, physical examination, prostate-specific antigen (PSA), or biopsy.
  • Prostatitis

    • Prostatitis is an inflammation of the prostate which can be caused by bacteria.
    • Prostatitis is an inflammation of the prostate which can be caused by bacteria.
    • The prostate is usually enlarged.
    • Chronic prostatitis is a rare condition .
    • PSA (prostate specific antigen) levels may be elevated.
  • Semen

    • During the process of ejaculation, sperm pass through the ejaculatory ducts and mix with fluids from the seminal vesicle, the prostate, and the bulbourethral glands to form semen.
    • The prostatic secretion, influenced by dihydrotestosterone, is a whitish (sometimes clear), thin fluid containing proteolytic enzymes, citric acid, acid phosphatase, and lipids.
    • After about 15–30 minutes, a prostate-specific antigen present in the semen causes the decoagulation of the seminal coagulum.
  • Antigens and Antigen Receptors

    • Note also that antibodies tend to discriminate between the specific molecular structures presented on the surface of the antigen.
    • Therefore, most antigens have the potential to be bound by several distinct antibodies, each of which is specific to a particular epitope.
    • In this case, they are called tumor-specific antigens (TSAs) and, in general, result from a tumor-specific mutation.
    • Antigen(ic) specificity is the ability of the host cells to recognize an antigen specifically as a unique molecular entity and distinguish it from another with exquisite precision.
    • Antigen specificity is due primarily to the side-chain conformations of the antigen.
  • Antigenic Determinants and Processing Pathways

    • An epitope, also known as an antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, and T cells.
    • The latter can use epitopes to distinguish between different antigens, and only binds to their specific antigen.
    • Epitopes determine how antigen binding and antigen presentation occur.
    • This is why polysaccharides are generally T-independent antigens and proteins are generally T-dependent antigens.
    • The determinants need not be located on the exposed surface of the antigen in its original form, since recognition of the determinant by T cells requires that the antigen be first processed by antigen presenting cells.
  • Antigen-Presenting Cells

    • Antigen presentation is a process where immune cells capture antigens and then enable their recognition by T-cells.
    • These antigens are different from those in bacteria ("non-self" antigens) or in virally-infected host cells ("missing-self").
    • Unlike B cells, T cells fail to recognize antigens in the absence of antigen presentation, with the important exception of the superantigens.
    • In the upper pathway; foreign protein or antigen (1) is taken up by an antigen-presenting cell (2).
    • In the lower pathway; whole foreign proteins are bound by membrane antibodies (5) and presented to B lymphocytes (6), which process (7) and present antigen on MHC II (8) to a previously activated T helper cell (10), spurring the production of antigen-specific antibodies (9).
  • Enzyme-Linked Immunosorbent Assay (ELISA)

    • Enzyme-linked immunosorbent assay (ELISA) is a method of quantifying an antigen immobilized on a solid surface.
    • ELISA uses a specific antibody with a covalently coupled enzyme.
    • The amount of antibody that binds the antigen is proportional to the amount of antigen present, which is determined by spectrophotometrically measuring the conversion of a clear substance to a colored product by the coupled enzyme.
    • The antigen serves as bridge, so the more antigen in the test solution, the more enzyme-linked antibody will bind .
    • The concentration of antigens can be inferred from absorbance readings of standard solutions.
  • Classes of T Cells

    • They have antigen receptors that are structurally related to antibodies.
    • These structures help recognize antigens only in the form of peptides displayed on the surface of antigen-presenting cells.
    • These include naive T cells that recognize antigens and are activated in peripheral lymphoid organs.
    • This activation results in the expansion of the antigen-specific lymphocyte pool and the differentiation of these cells into effector and memory cells.
    • Memory T cells are an expanded population of T cells specific for antigens that can respond rapidly to subsequent encounter with that antigen and differentiate into effector cell to eliminate the antigen.
  • Humoral Immune Response

    • The humoral immune response defends against pathogens that are free in the blood by using antibodies against pathogen-specific antigens.
    • An antigen is a biomolecule, such as a protein or sugar, that binds to a specific antibody.
    • Not every biomolecule is antigenic and not all antigens produce an immune response.
    • These membrane-bound protein complexes contain antibodies, which enable specific antigen recognition.
    • In most cases, the sensitized B cell must then encounter a specific kind of T cell, called a helper T cell, before it is activated.
  • Clonal Selection and Tolerance

    • Clonal selection occurs after immature lymphocytes express antigen receptors.
    • The preservation of useful specificities is called positive selection.
    • Negative selection is the process that eliminates developing lymphocytes whose antigen receptors bind strongly to self antigens present in the lymphoid organs.
    • "Self"-antigens from the body's own tissues 4.
    • Foreign antigen 6.
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