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PubMed1987

Establishment and characterization of a human myeloid cell line from Philadelphia chromosome-negative myeloblastic leukemia arising in a patient with myelodysplastic syndrome.

A new hematopoietic cell line derived from a patient with Philadelphia chromosome (Ph1)-negative myeloblastic leukemia arising from a form of myelodysplastic syndrome (MDS) is described. This cell line, designated TMM, consists of immature cells with the morphological characteristics of young myeloblasts and grows in suspension culture with a doubling time of about 30 hours. By cytochemical analysis the cultured cells were positive for acid phosphatase. They were free of the Epstein-Barr virus-associated nuclear antigen as well as terminal deoxynucleotidyl transferase. Further phenotypic analysis revealed the expression of the myelomonocytic-specific antigen Leu-M1 and receptors for the Fc portion of IgG. Partial differentiation of these cells could be induced by dimethyl sulfoxide, tetradecanoyl phorbol acetate, or hypoxanthine and resulted in cells of the myeloid series expressing lysozyme and receptors for the C3b complement protein. The karyotype was 46,XY, lacked the Ph1 chromosome, and displayed no abnormalities at the light microscopic level. No rearrangement of the bcr-c-abl gene complex was found. This cell line should be useful for studying an important type of the heterogeneous population constituting Ph1-negative myeloblastic leukemia, arising in this instance from MDS, as well as for studying differentiation and proliferation of human pluripotent stem cells.

Antigens, Neoplasm↗
PubMed1986

Relationship between the component and regulatory proteins of the classical pathway C3 convertase.

A relationship was found between the sums of the component proteins of the classical pathway C3 convertase (C2 and C4) and their regulators (C4bp and 1) in 184 normal controls. The relationship was maintained in most patients with low levels of individual components resulting from congenital deficiency and urinary losses, as well as in most cord sera. On the other hand, classical pathway activation in membranoproliferative glomerulonephritis type I, systemic lupus erythematosus, hereditary angioneurotic edema, and bacteremia resulted in loss of this relationship. Patients with alternative pathway-mediated complement activation (membranoproliferative glomerulonephritis type II) had a normal relationship between the classical component and regulatory proteins. In situations in which classical pathway activation is suspected, simultaneous examination of C4, C2, C4bp, and I may be helpful.

Angioedema↗
PubMed1979

A comparison of immunologic profiles and their influence on bacteremia in surgical patients with a high risk of infection.

Prospective sequential studies of the antibacterial function of neutrophils, lymphocyte responsiveness, opsonic capacity of serum and serum levels of C3(B), properdin, factor B, IgG, and albumin were made in 32 patients with severe burn injury (greater than or equal to 45%), 21 patients with severe multisystem traumatic injury, 20 high-risk, infected patients, and 22 renal transplant patients. Fifty-five episodes of bacteremia occurred in 37 of the 95 patients. Abnormal neutrophil function was clearly associated as a predisposing factor to these episodes, whereas there was no association between bacteremia and low serum levels of C3, IgG, factor B, or properdin. C3, factor B, and IgG usually rose following bacteremia as acute phase proteins, but there was evidence of a consumptive opsoninopathy in 11% of episodes. Defective opsonization was associated with a high risk of bacteremia only when there was a coexisting abnormality of neutrophil function (88% of such patients became bacteremic). None of 27 nonburned patients tested with delayed hypersensitivity antigens responded normally, and there was regularly depression of lymphocyte responsiveness to phytohemagglutinin-A and concanavalin-A in a whole blood assay related to serum immunosuppressive factors, but poor responsiveness was not associated with bacteremia.

Adolescent↗
PubMed1985

A synthetic nonapeptide corresponding to the NH2-terminal sequence of C3d-K causes leukocytosis in rabbits.

Numerous biologically active fragments have been described that are derived from the C3 molecule. Recently, a polypeptide (Mr 41,000) generated from the alpha chain of human iC3b by limited proteolysis with plasma kallikrein was shown to exhibit several biological functions. This C3-derived cleavage product, C3d-K, suppresses mitogen- and antigen-induced proliferation of human T-lymphocytes and induces leukocytosis in rabbits. We have identified and synthesized a portion of C3d-K that is associated with the leukocytosis phenomenon. A nonapeptide corresponding to the amino-terminal nine residues of C3d-K was synthesized using conventional Merrifield solid-phase peptide chemistry; the structure of this peptide is Thr-Leu-Asp-Pro-Glu-Arg-Leu-Gly-Arg (TLDPERLGR). At a final concentration of 4 X 10(-6) M, both the nonapeptide and the des-Arg octapeptide (TLDPERLG) were capable of inducing leukocytosis in rabbits. Additionally, both peptides enhance vascular permeability when injected in guinea pig skin. These activities are similar to those previously attributed to a C3 fragment identified as C3e by Ghebrehiwet and Müller-Eberhard (Ghebrehiwet, B., and Müller-Eberhard, H.J. (1979) J. Immunol. 123, 616-621). We conclude that the nonapeptide TLDPERLGR represents the active center of the C3-derived leukocytosis factors C3e and C3d-K. This active synthetic analogue of C3d-K should prove valuable in elucidating the mechanism of action for complement-dependent leukocyte mobilization in vivo.

Amino Acid Sequence↗
PubMed1985

Ontogeny of the third component of complement of Japanese quails.

Ontogeny of quail complement was examined in terms of serum C3 level, cytolytic activity of total complement, functional activity of C3 via the classical pathway (CCP) and an alternative route (ACP), and the distribution of C3-bearing cells. In serum, C3 was detected from 7-day-old embryos by rocket immunoelectrophoresis. Thereafter, its concentration increased rapidly and reached the adult level at 4-5 weeks of age. Total activities of serum complement via CCP and ACP, both of which were assayed by cell lysis, were detected first in 10-day-old embryos, and increased sharply after hatching, reaching the maximum level at 5 weeks of age. Deposition of C3 on the cell surface via CCP and ACP was also clearly demonstrated from 10-day-old embryos by haemagglutination and immunofluorescence techniques, respectively. By an immunofluorescence technique using anti-quail C3 monospecific serum, cells belonging to the reticuloendothelial system were indicated to serve major sites for the synthesis of C3 during ontogenesis.

Aging↗
PubMedDate not supplied

The biological role of the complement system and the clinical importance of complement measurements.

Properties of serum proteins belonging to the complement system, two pathways of the complement activation (classical and alternative pathway) as well as the physiological role of the complement system are discussed. Complement has essential importance in some physiological processes: In the induction of the humoral immune response, in the elimination of immune complexes and in the protection against bacterial and viral infections. After a short discussion of the genetics of the complement system, the principle and possibilities of clinical applications of the complement measurements are described. Finally, different approaches to the therapeutic manipulation of the complement system are discussed.

Angioedema↗
PubMed1982

Phagocytosis of bacteria by macrophages: changing the carbohydrate of lipopolysaccharide alters interaction with complement and macrophages.

Salmonella transductants and recombinants differing the O-antigenic side chain of their lipopolysaccharide are taken up at different rates by the murine macrophage-like cell line J774. Bacteria containing abequose, mannose, rhamnose, and galactose in O-antigenic side chain were taken up at the slowest rate; the one containing tyvelose instead of abequose was taken up at an intermediate rate; and the one containing mannose, N-acetylglucosamine, and glucose, instead of the above sequence, was taken up at the highest rate. These rates correlate well with the known virulence of these strains; the most virulent is the one taken up slowest, the one taken up at an intermediate rate is less virulent, and the one taken up fastest is the least virulent. The differences in ingestion rates reflect differences in affinity of the bacteria for the macrophages and not in the rate of ingestion once interaction has occurred, suggesting a receptor-mediated process. The majority of uptake is probably dependent on complement, as shown by the requirement for a serum component(s) destroyed by heating at 56 degrees C or by incubation with zymosan. Specific antibody is not required. We therefore postulate that relative virulence in vivo may reflect the relative ability of the polysaccharide of bacterial lipopolysaccharide to activate complement, thus determining the susceptibility of the bacteria to ingestion via the complement receptor of phagocytic cells.

Animals↗
PubMed1980

Three rat monoclonal antibodies to human C3.

Three monoclonal antibodies to human C3 have been obtained from a fusion of the rat myeloma line Y3 Ag 1.2.3. with spleen cells from rats immunized against C3. One, from clone 4, reacts with an antigenic determinant in C3c showing the expected reactivity of the 'C' antigen of C3. The specificity of the other two monoclonal antibodies correspond less clearly with known C3 antigens. By agglutination analysis of complement coated cells the determinant reacting with clone 3 is present in C3d while that for clone 9 appears as a neoantigen on C3bi. In both cases the co-precipitation results are anomalous and more direct studies are needed to define the exact specificity. The possibility that internal sequence duplications in C3 may explain some anomalies is discussed. None of the monoclonal antibodies significantly inhibit C3 functions. The monoclonal antibodies have been found to have unusual properties in co-precipitation assays being able to diffuse through a precipitation line with which they react to react with a further line. One antibody is also able to react strongly with the anodal half of what appears as a single line with a polyclonal antiserum.

Agglutination Tests↗