• Specialty
  • Cardiology
  • Dentistry
  • Dermatology
  • General Medicine
  • GI/GU
  • Hematology
  • Immunology
  • Lab Medicine & Pathology
  • Neuro-Psych
  • OB-Gyn
  • Oncology
  • Ophthalmology
  • Orthopaedic
  • Otolaryngology - ENT
  • Radiology
  • Surgery

• Immunology
  • AIDS HIV Terms
  • Immunization Terms
  • Immunology Terms
  • Sample Reports - Allergy / Immunology

• Immunology Terms

- I -

• Ia

Immune response-associated proteins, found on B cells and antigen-presenting cells of mice; an old term now replaced with MHC (major histocompatibility complex) class II molecules.



• Idiotype

The combined antigenic determinants (idiotypes) found on antibodies of an individual that are directed at a particular antigen; such antigenic determinants are found only in the variable region.



• Immediate-type hypersensitivity

Hypersensitivity tissue reaction occurring within minutes after the interaction of antigen and antibody.



• Immune adherence

The adherence of particulate antigen coated with C3b to tissue having cells with C3b receptors.



• Immune complex

Antigen bound to antibody.



• Immune modulators

Substances that control the expression of the immune response.



• Immune response (Ir) gene

A gene controlling an immune response to a particular antigen; most genes of this type are in the MHC (major histocompatibility complex), and the term is rarely used to describe other types of Ir genes outside the MHC.



• Immunogen

A substance capable of inducing an immune response (as well as reacting with the products of an immune response). Compare with antigen.



• Immunoglobulin (Ig)

A general term for all antibody molecules. Each Ig unit is made up of two heavy chains and two light chains and has two antigen- binding sites.



• Interferon

A group of proteins having antiviral activity and capable of enhancing and modifying the immune response.



• Interleukins

Glycoproteins secreted by a variety of leukocytes which have effects on other leukocytes.



• Internal image

A spatial configuration of the combining site of an anti-idiotype antibody which resembles the epitope to which the idiotype is directed.



• Intron

A segment of DNA that does not code for protein; the intervening sequence of nucleotides between coding sequences or exons.



• Isograft

A tissue transplanted between two genetically identical individuals.



• Isohemagglutinins

Antibodies to major red blood cell antigens present normally as a result of inapparent immunization by cross-reactive antigens in bacteria, food, etc.



• Isotype switch

The shift of a B cell or its progeny from the secretion of antibody of one isotype or class of antibody with the same V regions but a different heavy- chain constant region and, hence, a different isotype (class switch).



• Isotypes

Classes of antibody that differ in the constant region of their heavy chain (Fc portion); distinguishable also on the basis of reaction with antisera raised in another species. These differences also result in different biological activities of the antibodies.