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Serological and Genetic Studies of the HL‐A System
Author(s) -
Legrand L.,
Dausset J.,
Rapaport F. T.
Publication year - 1971
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/j.1537-2995.1971.tb04409.x
Subject(s) - antigen , antiserum , antibody , allele , serology , complement fixation test , microbiology and biotechnology , biology , immunology , chemistry , gene , genetics
Immunization of 35 recipients with skin allografts and leukocytes obtained from genetically haplo‐indentical donors induced the formation of antibodies directed against HL‐A antigens in 25 instances. The resulting antibodies could be divided into three main categories: (i) “broad” antibodies capable of reacting equally well with at least two allelic HL‐A specificities; (ii) “narrow” antibodies which reacted with one antigenic specificity, but could be absorbed by and eluted from cells bearing another specificity, without any cytotoxic reaction (CYNAP); (iii) antibodies which may be considered monospecific in the light of current knowledge. Antisera produced in the course of thir study have resulted in the definition of four new HL‐A antigens. Two of these, Da17 (HL‐A10) and Da25, were detected by the lymphmytotoxicity method, and have a gene frequency of 0.060 and 0.053, respectively. (The other two antigens, Da18 and Da22, were detected by the platelet complement fixation technic and have a gene frequency of 0.043 and 0.040, respectively.) Further absorption and elution of the antisera permitted the isolation of at least two populations of antibodies in a number of the immunized recipients. As a result, three HL‐A speciticities were subdivided into two allelic antigens: HG‐A9 was divided into HL‐A9′ and HL‐A9” HG‐AlO was divided into HL‐AlO' and HL‐A10” and Da25 was divided into Da25′ and Da25”. Review of the antigenic relationships existing between donors and recipienta in each of the 35 families studied indicates that (i) the occurrence of cross‐reacting antigens in donor and recipient is usually not associated with the production of antibodia (i.c, it constitutes a situation of nonimmunogenicity) and (ii) antibodies capable of reacting with one or several specificities, absent in the donor and in the recipient but which crossreact with the immunizing antigen, may occur with relative frequency. One other recipient developed three defferent antibody populations. Two of these antibodies were “broad” antibodies, capable of reacting with two allelic specificities. This observation supports the concept that the same munizing cell may bear several determinants, each of which may share a common structure with other defic products of the same locus. These data have been discuesed on the basis of two not mutually exclusive hypotheses: (i) complex antibodies capable of reacting with different allelic determinants and (ii) complex antigens bearing several antigenic factors.