Leigh C. Jefferies

Placental-Blood Banking — A New Frontier in Transfusion Medicine

Bone marrow has for years been the principal source of transplantable hematopoietic stem cells and progenitor cells. For bone marrow transplantation to succeed, it is crucial to find a donor whose ...

Naturally occurring anti-i/I cold agglutinins may be encoded by different VH3 genes as well as the VH4.21 gene segment.

In the current study, we wished to determine if the V regions encoding the naturally occurring anti-i/I Cold Agglutinins (anti-i/I CA) differ from pathogenic anti-i/I CA that are exclusively encoded by the VH4.21 gene. After EBV transformation of B lymphocytes, we generated one anti-I secreting clone from each of two individuals; clone 4G (individual CM, PBL) and clone Sp1 (individual SC, spleen). Clone 4G expresses a VH3 gene sequence that is 92% homologous to the germline gene WHG26. Clone Sp1 also expresses a VH3 gene that is 98% homologous to the fetally rearranged M85/20P1 gene. Another clone, Sp2 (anti-i specificity), from individual SC is 98% homologous to the germline gene VH4.21. For correlation, we studied anti-i/I CA fractions purified from 15 normal sera and found no or relatively small amounts of 9G4 (VH4.21 related idiotype) reactive IgM. Five cold agglutinin fractions contained large amounts of VH3-encoded IgM (compared to pooled normal IgM) by virtue of their binding to modified protein Staph A (SPA), and absorption of three CA fractions with modified SPA specifically removed anti-i/I binding specificity entirely. Collectively, the data indicate that naturally occurring anti-i/I CA may be encoded to a large extent by non-VH4.21-related genes, and that the VH4.21 gene is not uniquely required for anti-i/I specificity.

High deferral rate for maternal-neonatal donor pairs for an allogeneic umbilical cord blood bank.

BACKGROUND: To fully evaluate the safety and efficacy of umbilical cord blood (UCB) as a source of hematopoietic progenitor cells, UCB banks are being established worldwide to provide a readily accessible resource of stem and progenitor cells for allogeneic transplantation. Guidelines for UCB donor criteria have been proposed to minimize the possibility of disease transmission to UCB recipients.

Anti-idiotypic antibodies specific for a pathologic anti-Pr2 cold agglutinin

The heterogeneity of human red cell (RBC) autoantibodies may be assessed by using anti‐idiotypic antibodies. In this study, mouse monoclonal anti‐idiotypic antibodies were produced against a pathologic RBC autoantibody with anti‐Pr2 specificity. Epstein‐Barr virus‐transformed B‐cell clones were established from a patient who had splenic lymphoma and associated immune hemolysis due to an anti‐Pr2 cold autoantibody. Two of the eight clones producing this autoantibody were used to immunize mice for the establishment of hybridomas, and four monoclonal anti‐idiotypic antibodies were isolated (2 IgG1 kappa and 2 IgM kappa). By the use of these anti‐idiotypic antibodies, strong cross reactivity was seen on enzyme‐linked immunosorbent assay with other anti‐Pr2‐producing clones from the same patient, but no cross‐reactivity was seen with RBC autoantibodies from other individuals having anti‐Pr or different specificities. Each of the anti‐idiotypic antibodies inhibited hemagglutination (HA) by the patients anti‐Pr2 but failed to inhibit HA by antisera of a different RBC specificity. Cross‐competition experiments indicated that all of the anti‐idiotypic antibodies may recognize the same or a closely related idiotope on the anti‐Pr2 autoantibody. These studies suggested that the four anti‐idiotypic antibodies are directed against the same (or closely related) idiotypic determinant(s), unique to this patients anti‐Pr2 and located at or near the antigen‐binding site. These anti‐idiotypic antibodies may be useful tools for the study of this autoimmune response or for the development of immune therapeutic agents. Additional panels of anti‐idiotypic antibodies will be necessary to elucidate further the idiotypic diversity of RBC autoantibodies occurring both in healthy individuals and in patients with immune hemolysis.

[23] Production of carbohydrate-specific human monoclonal antibodies in vitro

Publisher Summary This chapter focuses on the production of carbohydrate–specific human monoclonal antibodies in vitro . The method described in this chapter is the current approach used in many laboratories to isolate autoreactive B-cells, with specificity for carbohydrate determinants on human red blood cells. The approaches that have been successfully employed for this purpose are quite diverse with respect to the initial seeding density of the lymphocytes, the activation of lymphocytes, cloning of cells under limiting dilution conditions, the presence of T lymphocytes, and the use of hybridomas. This diversity in methods is probably related to ultimate purposes for which the Epstein-Barr virus (EBV)-transformed B-cell clones have be used. For example, with regard to the initial seeding density of lymphocytes, it is important to evaluate the probable frequency of the desired (auto-) antigen-specific B cells in the source of these cells (peripheral blood, lymph node, spleen, and bone marrow).