globulin
[glob´u-lin] any of numerous proteins that are insoluble in water or highly concentrated salt solutions but soluble in moderately concentrated salt solutions. All plasma proteins except albumin and prealbumin are globulins. The plasma globulins are separated into five fractions by serum protein electrophoresis (SPE). In order of decreasing electrophoretic mobility these fractions are the alpha
1-, alpha
2-, beta
1-, and beta
2-globulins, and the gamma globulins.
The globulins include carrier proteins, which transport specific substances; acute phase reactants, which are involved in the inflammatory process; coagulation factors; complement components; and immunoglobulins. Examples are transferrin, a beta
1-globulin that transports iron, and alpha
1-antitrypsin, an acute phase reactant that inhibits serum proteases. The
gamma globulin fraction is almost entirely composed of
immunoglobulins.
antithymocyte globulin (ATG) the gamma globulin fraction of antiserum derived from animals (such as rabbits) that have been immunized against human thymocytes; an immunosuppressive agent that causes specific destruction of T lymphocytes, used in treatment of allograft
rejection. The term is sometimes used interchangeably with
antilymphocyte globulin. bacterial polysaccharide immune globulin (BPIG) a human
immune globulin derived from the blood plasma of adult human donors immunized with
Haemophilus influenzae type b, pneumococcal, and meningococcal polysaccharide vaccines; used for passive immunization of infants under 18 months of age.
cytomegalovirus immune globulin a purified
immunoglobulin derived from pooled adult human plasma selected for high titers of antibody against
cytomegalovirus; administered intravenously for treatment and prophylaxis of
cytomegalovirus disease in transplant recipients.
hepatitis B immune globulin (HBIG) a
specific immune globulin derived from plasma of human donors with high titers of antibodies against hepatitis B surface antigen (HBsAg); used for postexposure prophylaxis following contact with HBsAg-positive materials, also administered to infants of HBsAg-positive mothers.
hyperimmune globulin any of various
immune globulin preparations especially high in antibodies against certain specific diseases.
pertussis immune globulin a
specific immune globulin derived from the blood plasma of human donors immunized with pertussis vaccine; used for the prophylaxis and treatment of
pertussis.
respiratory syncytial virus immune globulin intravenous a preparation of
immunoglobulin G from pooled adult human plasma selected for high titers of antibodies against
respiratory syncytial virus; used for passive immunization of infants and young children.
Rh0(D) immune globulin a
specific immune globulin derived from human blood plasma containing antibody to the erythrocyte factor Rh
0(D); used to prevent Rh-sensitization of Rh-negative females and thus prevent
erythroblastosis fetalis in subsequent pregnancies; administered within 72 hours after exposure to Rh-positive blood resulting from delivery of an Rh-positive child, abortion or miscarriage of an Rh-positive fetus, or transfusion of Rh-positive blood. It is also used as a platelet count stimulator in the treatment of
idiopathic thrombocytopenic purpura.
serum g's all plasma proteins except albumin, which is not a globulin, and fibrinogen, which is not in the serum. The serum globulins are subdivided into alpha-, beta-, and gamma-globulins on the basis of their relative electrophoretic mobilities.
vaccinia immune globulin a
specific immune globulin derived from the blood plasma of human donors who have been immunized with vaccinia virus smallpox vaccine; used as a passive immunizing agent.
varicella-zoster immune globulin (VZIG) a
specific immune globulin derived from plasma of human donors with high titers of varicella-zoster antibodies; used for prevention or amelioration of
varicella in immunocompromised patients exposed to the disease and in neonates whose mothers develop varicella in the perinatal period.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.