Summary Introduction to the immune system

Introduction to the Immune System

Definitions:

 Pathogenicity- ability of microbe to induce disease
 Antigen- molecule that is recognised by the immune system
 Immunogen- part of antigen that induces immune reaction
 Epitope- part of antigen which is recognised by antibodies and T cells
 Antibody (immunoglobulin)- glycoprotein

Role of Immune System and Implications

 Defence against infections- Deficiency results in increased susceptibility to
infection whereas vaccination augments immune defences
 Immune system recognises and responds to tissue grafts and newly introduced
proteins- Immune responses are a barrier to transplants and gene therapy
 Defence against tumours- Potential for immunotherapy treatment of cancer
 Antibodies are highly specific for detecting classes of molecules- Immunological
testing can be used to test specificity

Immune System

 Innate:
 Born with this unspecific as first line of defence and produces the same response
each time
 Physical barrier- skin and mucosa
 Inflammation- when older so immediately ready to act
 Soluble factors- lysozyme, interferon and complementary antigens
 Myeloid cells- neutrophil, eosinophil, basophil, monocyte (phagocyte) and
lymphocyte (natural killer cells)
 Adaptive (Acquired):
 Adapts via cell mediated immunity (T cells) or humoral immunity (antibody
producing B cells) which can recognise and produce a greater response when
encountering a previous microbe
 Antigen recognition- younger need time to act and acquires immunity
 Lymphocytes- B cell, T cell, CD4 T cell and CD8 cytotoxic T cell




Leukocytes