Revue Fran?aise de Transfusion et Immuno-hématologie最新文献

Monoclonal antibodies against antigens of the M/N blood group system have been shown to be dependent on the microenvironment concerning their specificity [1, 3]. Therefore all the workshop antibodies were first tested at different pH and temperatures to investigate their binding specificity. Concerning the binding specificity another important aspect is the reactivity with enzyme treated red blood cells using trypsin, chymotrypsin and neuraminidase [2]. These tests were performed with all antibodies, which were positive in the direct agglutination tests.

An interesting evaluation for epitope specificity is the analysis of reactivity including inhibition studies using flow cytometry [4]. Binding studies were performed with all workshop antibodies with M- and N-RBC whereas inhibition studies were done only with monoclonals showing anti-M specificity.

Several examples of so called « Lutheran relatedmonoclonal antibodies have been described. With the exception of one anti-Lu^b [10] they have all shown the same serological reactivity in being weak or negative with the dominant type of Lu(a-b-) cells. Two have the specificity AnWj [5, 3] and others [12, 14] have different, as yet undefined, specificities. By virtue of their positive reactivity with the recessive type of Lu(a-b-) the antigens defined by these antibodies are not thought to be controlled by genes at the Lutheran locus and are not therefore Lutheran system antigens. Their relationship with the Lutheran system remains at the phenotypic level ; the antigens are regulated by a gene, referred to as either In(Lu) or SYN-IB, which also regulates Lutheran and several unrelated antigens on some rare cells — commonly referred to as the dominant type of Lu(a-b-) — referred to throughout this report as Lu(a-b-)d.

The monoclonal antibodies described in this report have been characterised with regard to specificity, thermal and pH optima, ionic strength dependence, enzyme sensitivity and sensitivity to aminoethylisothioronium bromide (AET) and dithiothreitol (DTT). Immunoglobulin class and subclass have been determined and immunoblotting performed with culture supernatants 9 W 11, 9 W 13 and 13 W 1.

In this work we studied 18 monoclonal antibodies (MAB_s) of various specificities directed against Rh, G and LW molecules. These antibodies were tested by agglutination techniques using a panel of human red blood cells (RBC) of common and rare phenotypes in order to:

• 1.

  Confirm their specificity

• 2.

  Investigate their reactivity with Rh variants

• 3.

  Determine their titres using various techniques.

Five monoclonal antibodies were studied ; one human and 4 murines. The human antibody (26 W 12) was anti-K. One of the murine antibodies (20 W 4) was very similar to anti-K and the other 3 (9 W 12, 19 W 2, 20 W 3) recognised high frequency antigens related to the Kell system through their absence from K₀ cells.

Until now there have been few reports on monoclonal antibodies reacting with antigens of the Kell system [2, 3, 4] and because of this only five monoclonal antibodies have been sent for investigation for this first workshop.

Monoclonal antibodies to erythrocyte membrane antigens have, prior to this investigation, led to identification of protein(s) which bear the Lu^b antigen [4] as well as to increased understanding of the effects of the in(Lu) gene [7, 8, 9, 10], a gene which acts in an autosomal dominant fashion to down-regulate expression of all Lutheran antigens as well as numerous other antigens recognized by human and murine monoclonal antisera [1, 2, 5]. This study was therefore designed to determine what, if any, further contribution could be made using the four submitted workshop antibodies toward the understanding of the biochemistry of Lutheran antigens and the mechanism of action of the In(Lu)