The G antigen is one of the erythrocyte membrane Rh antigens. The amount of Rh antigen present on the red blood cell is about 10(-15) g and radioactive labeling of membrane proteins is a useful method for its identification and characterization. In this paper, we compare 4 labeling techniques. Using a human monoclonal anti-Rh(G) antibody and an immunofixation technique, we located the G antigen on a polypeptide of an average molecular weight of 28,000 Da.

Antibodies, Monoclonal↗

PubMedDate not supplied

ABO-blood-group-related idiotypic network: mimicry of oligosaccharide epitope by rabbit antiidiotypic antibodies to murine monoclonal anti-A antibody.

The idiotypy of antibodies (Ab) specific for oligosaccharide determinants of blood groups of the human ABO system was studied through a cascade. Xenogenic antiidiotypic Ab (Ab2) raised in rabbits to the murine monoclonal anti-A61 (Ab1) were screened for reactivity with various anti-ABH Ab. Three anti-A and three anti-A,B monoclonal antibodies (mAb) which were developed in the same mouse strain as that producing Ab1, as well as a human polyclonal anti-A, were found to share cross-reactive idiotopes (CRI) with Ab1. CRI on murine mAb could be due to a Biozzi recurrent Id on anti-A Ab reacting with anti-Id "à la Oudin", while CRI on human anti-A Ab suggested the presence of paratope-induced anti-Id. Inhibition by Ab2 of haemagglutination of A, B or O human red blood cells by many murine anti-ABH mAb, and by polyclonal or monoclonal human anti-A, strongly supported the occurrence of anti-Id mimicking ABH epitopes belonging to type 2 determinants carried by human erythrocytes. Furthermore, a rabbit immunized with Ab2 produced a potent Ab3 response characterized by anti-H-type-2 specificity. Altogether, these results are consistent with the first successful production of anti-Id Ab that mimics the tridimensional shape of a well defined and strictly carbohydrate epitope, eliciting a haemagglutinating Ab3.

ABO Blood-Group System↗

PubMedDate not supplied

[Rare phenotypes of alpha-1 antitrypsin: study of a case of the M1X variant].

Alpha-1 antitrypsin is the major component responsible for the normal alpha 1 band in human serum. Some genetic variants giving double alpha-1 band, may be associated with pathological process. In the course of a systematic screening of blood donors a double-band alpha-1 pattern was observed in a serum, due to the heterozygous expression of a genetic variant of the PI system. A possible clinical significance of the variant was investigated by characterizing it. The very rare allotype PI*X was identified and its frequency in the population of french blood donors was estimated around to one for 10,000.

Adult↗

PubMedDate not supplied

[Immunogenetics of DNA polymorphism].

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Blood Group Antigens↗

PubMedDate not supplied

Blood group antigens in urinary bladder: from A antigen to A epitopes.

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ABO Blood-Group System↗

PubMedDate not supplied

Modeling studies of binding of sea raven type II antifreeze protein to ice.

Certain plants, insects, and fish living in cold environments prevent tissue damage due to freezing by producing antifreeze proteins or antifreeze glycoproteins that inhibit ice growth below the normal equilibrium freezing point of water in a noncolligative fashion. In polar fish these macromolecules, taking into account their structural characteristics, are grouped into three broad classes, namely Type I, Type II, and Type III. In this paper we report the results of our studies on the stereospecific binding of sea raven, a Type II antifreeze protein (AFP) to (111) hexagonal bipyramidal faces of ice. Earlier studies of Type I and Type III AFPs have shown that stereospecific binding of these proteins, recognizing specific planes of ice, is essential for their noncolligative antifreeze point depression. Moreover, as it has been shown for the AFT of Type I, this binding also occurs along specific vectors on these planes and also is enantioselective, distinguishing between the mirror related directions. In this study we will show, by using molecular modeling, that the fold of Type II AFP could facilitate a stereospecific mode of interaction with (111) planes of ice. Similar to Type I AFP, preferential directionality of binding was also observed in the simulations.

Amino Acid Sequence↗

PubMedDate not supplied

Quantitative and thermodynamic studies of erythrocytic ABO antigens.

This paper presents recent data from quantitative and thermodynamic investigations on A and B erythrocyte antigens. In regard to weak A phenotypes on the basis of quantitative data, practically no gap is observed from the weakest Aend to the strongest A3. Weak B phenotypes give a similar distribution. However, a more precise structural analysis including kinetics and thermodynamic measurements provides convincing evidence for the heterogeneity of each type of weak B reactive structures. Weak B antigens appear to be different from one to another, but similar inside one family. However, thermodynamics failed to demonstrate a qualitative difference between the weak B antigen in BX groups and the enhanced B antigen in ABX heterozygote, phenomenon that occurs in some very rare families. The same data were obtained from kinetic and thermodynamic analysis of B reactivity in cis AB samples; it can be assumed that such mutants are all different.

ABO Blood-Group System↗