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STRUCTURAL RELATIONSHIPS BETWEEN INDIVIDUAL H‐2 SPECIFICITIES ON THE CELL SURFACE
Author(s) -
Lengerová Alena,
Pěknicová Jana,
Pokorná Zora
Publication year - 1974
Publication title -
international journal of immunogenetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.41
H-Index - 47
eISSN - 1744-313X
pISSN - 1744-3121
DOI - 10.1111/j.1744-313x.1974.tb00311.x
Subject(s) - cytotoxicity , cytotoxic t cell , microbiology and biotechnology , biology , glycoprotein , molecule , cell culture , antigen , stereochemistry , chemistry , in vitro , biochemistry , biophysics , genetics , organic chemistry
SUMMARY Stepwise incubation with specific H‐2 antibody and rabbit‐anti‐mouse Ig was used to modulate the expression of selected H‐2 specificities on the surface of lymph node cells or EL 4 leukaemia cells. Modulation was reflected in a loss of sensitivity to complement‐dependent lysis and a polar pattern of immunofluorescence (‘capping’). Specificity H‐2.5 on H‐2 a cells was co‐modulated with H‐2.11 and so was H‐2.11 with H‐2.5 on H‐2 k cells. However, when H‐2.11 on H‐2 k cells was modulated, the cells did not loose cytotoxic sensitivity for H‐2.5. This asymmetry in co‐modulation of H‐2.5 and H‐2.11 may be accommodated by the duplication model of the H‐2 complex which postulates a double determination of H‐2.5 in the H‐2 k (unlike H‐2 a ) chromosome, with one determinant being in the K region (where also the H‐2.11 determinant is located) and the other in H‐2D. The modulation results with H‐2.5 and H‐2.11 are compatible with the view that various H‐2K specificities may represent distinct antigenic sites on the same glycoprotein molecule whereas H‐2D specificities are on separate molecule(s). The independent modulation of H‐2D.4 and H‐2K.11 specificities further indicates that molecules of the two classes are also secondarily not linked in the membrane structure. Modulation‐induced cytotoxicity resistance was further shown to persist even when the specific H‐2 antibody is newly added; this suggests that it is a change in the distribution of the H‐2 antigen to be held responsible (rather than the loss of the sensitizing antibody). A modulated expression of a certain H‐2 specificity might then be expected to affect its blocking relationship to another H‐2 specificity; the blocking index expresses the degree of interference by antibody attached to one of them with the attachment of antibody to the other. The blocking relationship between H‐2.4 and H‐2.11 was shown to be completely abolished by the independent modulation of H‐2.11. In contrast to this, the blocking index for H‐2.5 and H‐2.11 remained practically constant following the modulation of either specificity; this indicates that the intramolecular configuration of such two H‐2 sites may not be altered by the gross redistribution of the whole molecule in the plane of the membrane. The rigidity of this configuration seems to be maintained by neuraminidase‐sensitive groups as suggested by the reduced blocking index in neuraminidase pretreated cell.