E. Brunner

Comparative Studies on Anti‐Ag Sera in Immunodiffusion and in Passive Hemagglutination Methods

In previous publications, two of us (A.V. and G.M.) reported on isoprecipitins directed against human low density lipoprotein (LDL) which were detected in sera of multitransfused thalassemic patients from the area of Ferrara, Italy [11, 12, 131. These sera have been retested with regard to their seroIogica1 behaviour and specially to the specificity of their antibodies. The investigations included, on the one hand, comparative immunodiffusion and absorption experiments, and, on the other hand, a new and sensitive hemagglutination assay which has been previously described by two of us (R.B. and E.B.) [4]. Results of this comparative study are presented in the €allowing report.

A New Sensitive Method for Studying the Polymorphisms of the Human Low Density Lipoproteins

The group-specific, genetically determined factors of the human low density lipoproteins (LDL) were up to now determined by means of the Ouchterlony technique, using isoprecipitin containing sera from patients, or immune sera containing heteroprecipitins from animals. The disadvantages of this method have already been discussed elsewhere [3]. In particular, attention has been drawn to its relative insensitivity, and to the possibility that anti-LDL immune sera may contain non-precipitating antibodies, thus requiring other techniques for their detection. For this reason we have studied different methods of detecting non-precipitating antibodies and their possible application to our problem; the results of these investigations will be presented in detail separately. Based on the finding by BEAUMONT [l] that LDL can be fixed to erythrocytes by diazotisation, we tried to apply similar techniques to the study of the LDL polymorphisms. We limited ourselves in the beginning to the estimation of factor Ag(x) with the aid of our anti-Ag(x) serum Gi [2]. At first, the question arose whether the Ag(x) determinant was destroyed by the process of diazotisation.

Ag(i): Detection of an Antithetical Factor to Ag(h)

Abstract. A trispeciflc anti‐Ag serum (M. H.) was found to reveal a new Ag factor: Ag(i). Ag(i) occurs in 98.3% of the white population and is antithetical to Ag(h). The results of Ag(i) typing in Swiss, Tibetans and Senegalese are amalgamated with previously obtained genetic data. Different models for the Ag chromosome are discussed.

Contribution to the genetics of serum β-lipoproteins in man

SummaryAllelism of the genes Agt and Agz and their close linkage to the Agx/y, Aga1/d and Agc/g loci is now confirmed from the study of the segregation ratios in 28 families.ZusammenfassungDurch eine Unterschung der Segregationsrate in 28 Familien konnte die Allelität der Gene Agt und Agz und ihr komplettes “linkage” zu den Agx/y, Aga1/d und Agc/g Loci bestätigt werden.

Ag(d), a further factor of the Ag-system.

In the course of an investigation on a number of sera from multitransfused Greek children with Cooley anemia, two sera (D S and CF) with a completely concordant serological behaviour were observed. These two sera appeared especially interesting as they proved to be polyspecific ; besides anti-Ag(y) the presence of a t least one further identical antibody with an unknown specificity had to be assumed [l]. As will be shown below, sera DS and C F turned out to be trispecific, one antibody revealing a new specificity which we tentatively called Add).

The role of rheumatoid factor and related human antiglobulins in the radioimmunoassay (Ausria system) for the detection of hepatitis B antigen.

Abstract. Of a total of 111 sera containing RF, 110 did not give false‐positive RIA results with the Ausria system; in only one case the influence of RF on the RIA result could not be completely excluded. Thus, false‐positive RIA results due to rheumatoid factor, if occurring at all, are apparently very infrequent. The same conclusion could be drawn for anti‐Gm, anti‐Inv and other human antiglobulins.