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roles of carrier proteins. The identification and usefulness of blood group antigens as markers will be described and possible explanations for their variation in expression will be discussed. Most red cell antigens have been investigated because they are clinically important [1]. The antibodies to some antigens have caused haemolytic disease of the newborn and/or transfusion reactions. Other antigens are involved in haemolytic anaemia and some are important in transplantation. Red cell antigens provided a tool for investigation of the red cell surface and for use as genetic, immunological and biochemical markers. More than 500 red cell antigens are serologically defined, about half of which have been officially recognised and have been numbered by the International Society of Blood Transfusion Working Party on Terminology for Red Cell Surface Antigens [2,3]. Antigens are divided into systems (antigens controlled by a locus or closely linked loci) and three holding files: collections (related antigens whose genetic relationship is unknown), antigens of high incidence or antigens of low incidence. THE MAIEA TECHNIQUE Sometimes if an antigen has a very high or a very low incidence it is hard to relate it to other antigens or to assign it to a system. Immunochemical studies and in the case of high incidence antigens, use of cells of rare phenotype can be informative and recently the MAIEA technique, monoclonal antibody specific immobilisation of erythrocyte antigens, has proved useful. MAIEA was an adaptation of a technique, MAIPA, frequently used for studying platelets. MAIEA can be used to assign red cells antigens, as recognised by human alloantisera, to particular components of the red cell membrane [4]. Location of antigens on specific red cell membrane components The Knops system consists of 4 high incidence antigens Kna, McCa, Sla and Yka with frequencies greater than 90% in populations tested. There is also a low incidence antigen Knb found in Whites [3]. The antibodies to these public antigens are difficult to identify serologically. The antigens show a wide variation of strength on different donor’s cells. There is a null phenotype, the Helgeson phenotype, which appears from serological tests to lack all 4 antigens [5]. Cells which lack one Knops antigen may have weakened expression of other Knops antigens. The mists about these serologically difficult antigens were cleared when Moulds et al [6] and Rao et al [7] independently showed that these antigens were carried on the CR1 (complement receptor 1, CD35) protein. The related antigen Csa was not located on CR1, so Csa and Csb were left in the Cost collection [3].
DOI link for roles of carrier proteins. The identification and usefulness of blood group antigens as markers will be described and possible explanations for their variation in expression will be discussed. Most red cell antigens have been investigated because they are clinically important [1]. The antibodies to some antigens have caused haemolytic disease of the newborn and/or transfusion reactions. Other antigens are involved in haemolytic anaemia and some are important in transplantation. Red cell antigens provided a tool for investigation of the red cell surface and for use as genetic, immunological and biochemical markers. More than 500 red cell antigens are serologically defined, about half of which have been officially recognised and have been numbered by the International Society of Blood Transfusion Working Party on Terminology for Red Cell Surface Antigens [2,3]. Antigens are divided into systems (antigens controlled by a locus or closely linked loci) and three holding files: collections (related antigens whose genetic relationship is unknown), antigens of high incidence or antigens of low incidence. THE MAIEA TECHNIQUE Sometimes if an antigen has a very high or a very low incidence it is hard to relate it to other antigens or to assign it to a system. Immunochemical studies and in the case of high incidence antigens, use of cells of rare phenotype can be informative and recently the MAIEA technique, monoclonal antibody specific immobilisation of erythrocyte antigens, has proved useful. MAIEA was an adaptation of a technique, MAIPA, frequently used for studying platelets. MAIEA can be used to assign red cells antigens, as recognised by human alloantisera, to particular components of the red cell membrane [4]. Location of antigens on specific red cell membrane components The Knops system consists of 4 high incidence antigens Kna, McCa, Sla and Yka with frequencies greater than 90% in populations tested. There is also a low incidence antigen Knb found in Whites [3]. The antibodies to these public antigens are difficult to identify serologically. The antigens show a wide variation of strength on different donor’s cells. There is a null phenotype, the Helgeson phenotype, which appears from serological tests to lack all 4 antigens [5]. Cells which lack one Knops antigen may have weakened expression of other Knops antigens. The mists about these serologically difficult antigens were cleared when Moulds et al [6] and Rao et al [7] independently showed that these antigens were carried on the CR1 (complement receptor 1, CD35) protein. The related antigen Csa was not located on CR1, so Csa and Csb were left in the Cost collection [3].
roles of carrier proteins. The identification and usefulness of blood group antigens as markers will be described and possible explanations for their variation in expression will be discussed. Most red cell antigens have been investigated because they are clinically important [1]. The antibodies to some antigens have caused haemolytic disease of the newborn and/or transfusion reactions. Other antigens are involved in haemolytic anaemia and some are important in transplantation. Red cell antigens provided a tool for investigation of the red cell surface and for use as genetic, immunological and biochemical markers. More than 500 red cell antigens are serologically defined, about half of which have been officially recognised and have been numbered by the International Society of Blood Transfusion Working Party on Terminology for Red Cell Surface Antigens [2,3]. Antigens are divided into systems (antigens controlled by a locus or closely linked loci) and three holding files: collections (related antigens whose genetic relationship is unknown), antigens of high incidence or antigens of low incidence. THE MAIEA TECHNIQUE Sometimes if an antigen has a very high or a very low incidence it is hard to relate it to other antigens or to assign it to a system. Immunochemical studies and in the case of high incidence antigens, use of cells of rare phenotype can be informative and recently the MAIEA technique, monoclonal antibody specific immobilisation of erythrocyte antigens, has proved useful. MAIEA was an adaptation of a technique, MAIPA, frequently used for studying platelets. MAIEA can be used to assign red cells antigens, as recognised by human alloantisera, to particular components of the red cell membrane [4]. Location of antigens on specific red cell membrane components The Knops system consists of 4 high incidence antigens Kna, McCa, Sla and Yka with frequencies greater than 90% in populations tested. There is also a low incidence antigen Knb found in Whites [3]. The antibodies to these public antigens are difficult to identify serologically. The antigens show a wide variation of strength on different donor’s cells. There is a null phenotype, the Helgeson phenotype, which appears from serological tests to lack all 4 antigens [5]. Cells which lack one Knops antigen may have weakened expression of other Knops antigens. The mists about these serologically difficult antigens were cleared when Moulds et al [6] and Rao et al [7] independently showed that these antigens were carried on the CR1 (complement receptor 1, CD35) protein. The related antigen Csa was not located on CR1, so Csa and Csb were left in the Cost collection [3].
ABSTRACT