[New findings on an anti-proteinase in human plasma: l'inter-alpha-trypsin inhibitor]

Inter-alpha-trypsin inhibitor (I alpha I) has been purified from C.N.T.S. fraction III as starting material. The purification procedure includes D.E.A.E. cellulose chromatography and gel filtration on G 150 Sephadex in the presence of EDTA. The purified protein gives one precipitation line in immunoelectrophoresis against anti-whole human sérum. It reacts only with an anti I alpha I immune serum and possesses a strong antitryptic activity. When studied in starch or polyacrylamide gel electrophoresis 2 components are observed, each of them having the same antigenic structure and the same antitryptic activity as the crude preparation. The slower and less important component is dissociated by 0,1% SDS. The molecular weight estimation of I alpha I BY PAA/SDS is about 180,000. This result is not modified by the presence of 1% beta mercaptoethanol indicating that I alpha I consists of one polypeptide chain. Crude preparation reveals under the same electrophoretical conditions small amounts of low molecular weight components (135,000 52,000 and 26,000) which can be due to a proteolytic action on I alpha I. Indeed plasmin is able to produce such fragments having an antitryptic activity as shown by fibrin/polyacrylamide gel electrophoresis. The relationship between small molecular weight inhibitors of human serum and bronchial secretions and those obtained after degradation of I alpha I by plasmin is discussed.

Distribution of heavy chain classes and light chain types in 757 cases of monoclonal gammapathies

The distribution in heavy chain classes and light chain types of M components were studied in 757 cases of monoclonal gammapathies. These gammapathies were classified according to clinical and hematological data in 439 myeloma (MM), 165 Waldenström's macroglobulinemia (WM) and 152 monoclonal gammapathies occurring in other conditions. The IgG/IgA ratio differs in myeloma and in non-myelomatous gammapathies (64% IgG versus 33% IgA in myeloma and 95% IgG versus 5% in absence of myeloma). Presence of free light chains in patient's urines (Bence Jones proteinuria) was detected in about 72% of cases of MM, 48% of WM and only in 9% in others gammapathies. Concerning the sex of patients, an equal repartition between males and females is observed in MM, whereas males predominate in WM. The age distribution of the patients shows that 74% of myeloma and 79% of WM were above sixty. In addition to the 757 cases under study, 10 sera with two M Components were characterized.

Analysis of a fibrin formation abnormality in a case of multiple myeloma

Studies were performed to analyse the inhibitory effect of a myeloma globulin (IgG) on fibrin formation. This inhibitory activity was very intense and caused a severe bleeding disorder which proved fatal. The isolated myeloma globulin inhibited all three stages of fibrin formation: the proteolytic action of thrombin on fibrinogen, the aggregation of fibrin monomers and the stabilization of fibrin by cross-linkages in the gamma and alpha chains. Purified factor XIII, even in excess, previously activated by the addition of thrombin and calcium, did not correct this defect in cross linking. Our results suggest that this myeloma globulin induced a blockage of some receptors near the cross linking sites.

[Studies on human alpha-2 macroglobulin structure and its complexes with proteases, using polyacrylamide gel electrophoresis]

Pure alpha2M is prepared with fresh plasma as starting material, to prevent the interaction of alpha2M from proteolytic enzymes of plasma such as thrombin, plasmin and kallikrein. During the purification steps, polybrene and aprotin are used as inhibitors and plasminogen is absorbed onto bentonite. When alpha 2M is submitted to polyacrylamide gel electrophoresis (PAA) containing 0.1% SDS, a complete dissociation in two half-molecules of MW 380,000 occurs. When alpha2M is incubated in 1% SDS and 1% beta-mercaptoethanol as reducing agent, only one component of MW 190,000 is observed in PAA-SDS. This experiments show that the alpha2M molecule consist of two symetric halves of same MW (380,000) linked by non covalent bonds. Each two-half-molecules is made of two polypeptides chains MW 190,000 linked by disulfide bonds. Thus alpha2M molecule contains four polypeptides chains having a same MW. The same techniques were applied to the study of alaph2M proteinases complexes. Three different proteinases (plasmin, trypsin and papain) were used in these experiments. Trypsin and papain are commercialy available. Plasminogen was obtained by affinity chromatography and activated into plasmin by insoluble streptokinase fixed on PAB cellulose.