In the present study we present evidence that the proportion of complement-receptor lymphocytes (CRL) Is greatly increased in the circulation In most cases of chronic lymphocytic leukemia (CLL). Lymphocytes (> 990/0 pure, 700/0 recovery) were obtained from the peripheral blood of normal Individuals by separation of the mononuclear cells from the leukocyte-enrlched plasma by differential flotati...

Certain complement defects are associated with an increased propensity to contract Neisseria meningitidis infections. We performed detailed analyses of complement-mediated defense mechanisms against N. meningitidis 44/76 with whole blood and serum from two adult patients who were completely C2 or C5 deficient. The C5-deficient patient and the matched control were also deficient in mannose-bindi...

Acute thermal injury of rat skin produces an early, acute hemoglobinemia that is associated with the presence in blood of osmotically fragile red cells (RBC) that do not contain on their surfaces measurable amounts of complement components. The hemoglobinemia and the appearance in blood of osmotically fragile RBC appear to be the result of complement activation, which leads to oxygen radical pr...

We have previously described a panel of four monoclonal antibodies (MoAbs) reactive with antigens expressed on tumor cells from small cell carcinoma of the lung (SCCL). These IgM MoAbs are cytotoxic to SCCL cells in the presence of complement and thus have potential as reagents for the removal of SCCL cells contaminating bone marrow autografts. Therefore, we examined the cytotoxicity of these M...

IgM antibodies specific for a certain antigen can enhance antibody responses when administered together with this antigen, a process believed to require complement activation by IgM. However, recent data show that a knock-in mouse strain, Cμ13, which only produces IgM unable to activate complement, has normal antibody responses. Moreover, the recently discovered murine IgM Fc receptor (FcµR or ...

BACKGROUND Antibodies to factor H (fH)-binding protein (fHBP), a meningococcal vaccine antigen, activate classical complement pathway serum bactericidal activity (SBA) and block binding of the complement inhibitor fH. METHODS To understand these 2 functions in protection, we investigated the interactions of human complement and 2 anti-fHBP monoclonal antibodies (MAbs) with encapsulated Neisse...

Methods to assess immunocompetence requiring only a single sample are useful in comparative studies where practical considerations prevent holding or recapturing individuals. The assay for natural antibody-mediated complement activation and red blood cell agglutination described here, requiring approximately 100 microl of blood, is highly repeatable. The effects of complement deactivation, 2-me...

BACKGROUND In addition to its complement-regulating activity, CD55 is a ligand of the adhesion class G protein-coupled receptor CD97; however, the relevance of this interaction has remained elusive. We previously showed that mice lacking a functional CD97 gene have increased numbers of granulocytes. METHODOLOGY/RESULTS Here, we demonstrate that CD55-deficient mice display a comparable phenoty...

Heparin-imprinted synthetic polymer surfaces with the ability to attenuate activation of both the complement and the coagulation system in whole blood were successfully produced. Imprinting was achieved using a template coated with heparin, a highly sulfated glycosaminoglycan known for its anticoagulant properties. The N,N'-diacryloylpiperazine-methacrylic acid copolymers were characterized usi...

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonal blood disorder that manifests with hemolytic anemia, bone marrow failure, and thrombosis. Many of the clinical manifestations of the disease result from complement-mediated intravascular hemolysis. Allogeneic bone marrow transplantation is the only curative therapy for PNH. Eculizumab, a monoclonal antibody that blocks terminal compleme...