C8 binding protein (C8bp) is an integral membrane glycoprotein of peripheral blood cells, which inhibits the C5b-9-mediated lysis in a homologous system. In the present study, we analyzed the carbohydrate portion of the C8bp. We found that C8bp is associated with I antigenic determinant, a sugar sequence found on human erythrocytes of adults. To assess whether or not the sugar residues are essential for the C8bp function, I determinant was cleaved off from the isolated C8bp by endo-beta-galactosidase (E.C. 3.2.2.103) that hydrolyses internal beta-galactosidic-linked-N-acetyllactosamine residues. Enzyme treatment removed I-antigen, the inhibitory function of C8bp, however, was not affected. When intact erythrocytes were treated with endo-beta-galactosidase, I-antigen was lost and the lytic insusceptibility of human erythrocytes to homologous C5b-9 could not be abolished. Thus, I-antigen is associated with the C8bp, but its presence is not required for the homologous species restriction.

Blood Proteins↗

PubMedDate not supplied

Hepatitis C-virus (HCV) antibodies in patients after kidney transplantation.

The hepatitis C-virus (HCV) is the main etiologic agent of posttransfusion hepatitis (PTH). Most patients depending on hemodialysis need transfusion of blood before kidney transplantation. Of 272 patients after kidney transplantation, 27 (10%) were found to be anti-HCV-ELISA-positive (HCV-Antibody-ELISA, Ortho Diagnostics). The antibodies could be neutralized by HCV C-100-3 antigen. Eight of 22 patients (36%) who had more than one kidney transplantation were classified anti-HCV positive [30% (8/27) of all anti-HCV positive patients]. The number of transfused blood units ranged from 0 to 99 BU. Receiving more than one kidney graft or the transfusion of more than 5 units of blood increased the risk for HCV infection 3.5 or 4.1 times, respectively, compared with one transplantation or less than 5 units of blood. No significant interactions were seen between these two variables. Of the anti-HCV positive patients, 48% were anti-HBc negative as well as HBs-antigen negative, 52% were anti-HBc positive.

Adult↗

PubMedDate not supplied

Actual aspects of cold agglutination.

Cold agglutinins (CA) can be directed against antigens of the I/i system and the Pr complex. In addition, anti-Gd CA have been recently described. The CA immunoglobulins, serological specificities and the antigen immunochemistry are reviewed. CA permitted studies on interrelations between antibody structures and specificities. The significance of subgroup preferences and cross-idiotypic specificities is discussed. Interrelations between CA specificities and certain virus infections are pointed out, and recent results obtained from studies using CA as indicators for membrane alterations of other than red cells are reviewed.

ABO Blood-Group System↗

PubMedDate not supplied

Characterization of various anti-Pr cold agglutinins.

Forty -one samples of anti-Pr cold agglutinins (CA) were studied. The titers ranged from 4 to 32,000. As is the case with cold agglutinins of other specificities, immunoglobulin class M and k-type light chains predominated with anti-Pr CA. On the other hand, the few IgM lambda, IgG, and IgA found were associated preferentially with anti-Pr specificity. All anti-Pr CA were inhibited by human red cell membrane sialoglycoproteins. On the basis of an increased inhibition by sialoglycoproteins after periodate oxidation and carbodiimide treatment, respectively, three anti- Pr2 and five anti-Pr3 were found. Among 24 anti-Pr1 CA subclassified on the basis of agglutination with dog red cells, six were anti- Pr1h , 16 were anti- Pr1d , and two did not fit into the subclassification. Similar to the anti- Pr1h , - Pr1d subclassification, anti-Pr3 CA could be subclassified into anti- Pr3h , - Pr3d . Three anti-Pra examples were found. None of the anti-Pr CA was inhibited by N-acetylneuraminic acid; some (5/35) were inhibited by sialyllactose, NeuAc alpha 2-3 2-6 Gal beta 1-4Glc, in high doses (5.0-20.0 mM).

Aged↗

PubMedDate not supplied

Inhibition of an anti-Pr1d cold agglutinin by citrate present in commercial red cell preservative solutions.

A patient with known cold autoimmune hemolyticanemia was admitted for surgery. Routine cold agglutinin evaluations, using commercial red cells (RBCs) in modified Alsever's preservative solution, revealed a cold agglutinin titer of 4 to 16. However, using RBCs washed four times with saline, a high-titer (greater than 2000 at 4 degrees C) cold autoagglutinin was demonstrated. The cold agglutinin was shown to be an IgM kappa paraprotein with anti-Pr1d specificity. The addition of Alsever's solution to washed RBCs inhibited the cold agglutinin. Each major component of Alsever's solution (neomycin, chloramphenicol, inosine, dextrose, and citrate) was tested individually; only citrate inhibited the patient's cold agglutinin. Various compounds structurally related to citrate were tested and found to cause various degrees of inhibition. The strongest inhibition correlated with the presence of either three carboxyl groups on molecules devoid of double-bonded carbon atoms or two carboxyl groups in cis configuration. A panel of 54 cold agglutinins, including 7 with anti-Pr specificity, was analyzed. None was significantly inhibited by Alsever's solution, although one with anti-Pr2 specificity was weakly inhibited. In summary, these studies describe an anti-Pr1d cold autoagglutinin that was inhibited by citrate in RBC preservative solutions. The failure to detect such a cold agglutinin can result from not washing RBCs free of citrate before testing.

Aged↗