Allotypes localization

Allotypic localization in the cell was analyzed in a number of experiments in the lymphoid tissue of rabbits (Pernis et al., 1965). With the aid of antiserums to allotypes which are controlled by allelic genes (the combinations and Al for locus Aa Ab" and Ab Ab" and Ab , Ab" and Ab for locus Ab were investigated) the presence of two populations of plasma cells was demonstrated. Each of these populations contained only one of the two allotypes. In general both types of cell are distributed randomly. However, there were fields which showed the predominance of one of them. 

Pemis, B., Chiappino, G., Kelus, A.S., Gell, P.G.H. (1965). Cellular localization of immunoglobulins with different allotypic specificities in rabbit lymphoid tissues. J. Exp. Med. 122,853-876. 

Table III. Localization of Certain Human Allotypic Markers"...

Localization of certain human allotypic markers. Refer to Fig. 1 for lineeir location within the heavy-chain constant region of the various IgG subclasses. 

Intramolecular localization of rabbit allotypic determinants. See text and Fig. 2 for more detailed description. 

Each of a group of homogeneous antibodies tested was found to express the full range of allotypic specificities controlled by the b locus (53). The difference, as compared to the a.Iocus, may reflect localization of most group b specificities to the C region of the L chain group a specificities are apparently confined to the Vh region. 

It appears that g74 and g75 each represent a set of allotypic determinants, present on both the Fab and Fc fragments. For example, in an Ouchterlony test with anti-g74 antiserum either fragment, Fab or Fc, forms a precipitin band which shows only partial identity with intact sIgA i.e., each fragment reacts but is antigenically deficient as compared to the intact molecule. Also, the g74 specificities on Fab and Fc are antigenically distinct from one another. Similar results were obtained with anti-g75 antisera. Specificities controlled by the /locus have not been localized to fragments Fab or Fc because of the resistance of such IgA molecules to papain (111,112). 

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