Anti-fibrotic Effects of CXCR4-Targeting i-body AD-114 in Preclinical Models of Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrotic lung disease that is prevalent in individuals >50 years of age, with a median survival of 3-5 years and limited therapeutic options. The disease is characterized by collagen deposition and remodeling of the lung parenchyma in a process that is thought to be driven by collagen-expressing immune and structural cells. The G-protein coupled C-X-C chemokine receptor 4, CXCR4, is a candidate therapeutic target for IPF owing to its role in the recruitment of CXCR4+ fibrocytes from the bone marrow to fibrotic lung tissue and its increased expression levels by structural cells in fibrotic lung tissue. We have engineered a novel fully human single domain antibody "i-body" called AD-114 that binds with high affinity to human CXCR4. We demonstrate here that AD-114 inhibits invasive wound healing and collagen 1 secretion by human IPF fibroblasts but not non-diseased control lung fibroblasts. Furthermore, in a murine bleomycin model of pulmonary fibrosis, AD-114 reduced the accumulation of fibrocytes (CXCR4+/Col1+/CD45+) in fibrotic murine lungs and ameliorated the degree of lung injury. Collectively, these studies demonstrate that AD-114 holds promise as a new biological therapeutic for the treatment of IPF.

Graded compression ultrasonography in the assessment of the "tough decision" acute abdomen in childhood.

The diagnosis of acute appendicitis in childhood is frequently difficult. In some situations the need to operate is clear, but in others the decisions may be much "tougher" because the clinical findings are equivocal. This is a retrospective study of a consecutive series of 253 children presenting with "acute abdominal pain? appendicitis" who had graded compression ultrasonography (GCUS) because the clinical scenario did not warrant immediate laparotomy. This represents 30% of all cases seen in the study period. The aim of the study was to examine the role of GCUS and a clinical scoring system (the Alvarado score) in patients in whom the diagnosis is uncertain.

Absence of continuous epitopes in the house dust mite major allergens Der p I from Dermatophagoides pteronyssinus and Der f I from Dermatophagoides farinae.

BACKGROUND: The house dust mite has been shown to be an important source of domestic allergens associated with immediate hypersensitivities. The Group I mite allergens Der p I from Dermatophagoides pteronyssinus and Der f I from D. farinae display extensive amino acid sequence homology and have similarities with cysteine protease enzymes. OBJECTIVE: The availability of the complete amino acid sequences for these allergens allowed us to search for the allergic determinants within these molecules. The aim of the present investigation was to identify any continuous IgE-binding epitopes within these amino acid sequences. We also sought to test the validity of previously reported Der p I peptide epitope sequences. METHODS: In order to identify any continuous IgE epitopes, the amino acid sequences of Der p I and Der f I were synthesized as decapeptides overlapping in sequence and coupled to plastic pins. The specific IgE-binding capacity of these peptides was assayed using an enzyme-linked biotin-streptavidin procedure and sera from patients known to be sensitive to these allergens. Previously reported Der p I peptide epitopes were synthesized as free peptides and tested for their ability to inhibit specific IgE binding to allergen extract discs. RESULTS: None of the pin-coupled Der p I or Der f I peptides was found by the continuous epitope mapping procedure to bind significantly to specific IgE in the sera of hypersensitive patients. The previously reported Der p I peptide epitopes did not inhibit specific IgE binding to mite extract discs. CONCLUSION: The specific IgE binding epitopes of the house dust mite allergens Der p I and Der f I are discontinuous in nature.

[Promotive effects of thymus peptide on mitogen-induced child thymocyte proliferation].

This paper reports a cytocentrifugation study of the morphological changes of mitogen-induced proliferating child thymocytes stimulated by thymus peptides. The proliferation response of child thymocytes to PHA was far more significant than those to ConA and PWN. This differs from the more pronounced effect of ConA on thymocyte proliferation in mice. In vitro, child thymocytes did not respond to thymus peptide without mitogen-induction. However, when thymus peptide was added to thymocyte culture with PHA, ConA, or PWN, proliferation responses were significantly enhanced, being most marked in the PHA-induced cell culture. The mechanism of the enhancing effect of thymus peptide on mitogen-induced human thymocytes is discussed.

Antibodies to polyclonal IgA, IgA1, and IgA2 and isotype-specific immune complexes in IgA nephropathy.

The concentrations of serum IgG and IgM antibodies to polyclonal IgA (IgAp), IgA1, and IgA2 were determined by enzyme immunoassay in 31 patients with IgA nephropathy and 30 healthy controls. Patients with IgA nephropathy had significantly raised concentrations of serum IgA compared to controls (Mann-Whitney U test, P = 0.001) and increased concentrations of conglutinin-binding IgA immune complexes (P = 0.024). No differences in the median concentrations of IgG and IgM anti-IgA antibodies were found between the patients and the controls. In serum samples from healthy controls there was a significant positive correlation between IgM anti-IgAp and IgA immune complex concentrations (P = 0.05), which contrasted with the finding of an inverse correlation between IgM anti-IgAp and IgA immune complex concentrations in patients with IgA nephropathy (P less than 0.05). In addition, the concentrations of conglutinin binding IgM immune complexes in serum were found to correlate with the concentration of IgM anti-IgAp (0.010 less than P less than 0.025), IgM anti-IgA1, and IgM anti-IgA2 (P much less than 0.005 for both) in patients with IgA nephropathy but not in controls. IgM anti-IgA antibodies may be important in augmenting the clearance of IgA immune complexes from the serum of patients with IgA nephropathy.

Anti-IgA antibodies in IgA-deficient children.

IgG and IgM isotype antibodies to polyclonal human IgA, myeloma IgA1, and myeloma IgA2 were estimated in 38 IgA-deficient children aged between 0.9 and 15 years. All children had IgM anti-IgA antibodies. IgG antibodies against either polyclonal IgA, IgA1, or IgA2 were present in 63% of the IgA-deficient children. IgG anti-IgA antibodies were detected against all three antigens in 8 of 11 severely IgA-deficient children and in 7 of 27 partially IgA-deficient children, but in only 1 of 23 healthy adult controls. The proportion of children with IgG anti-IgA antibodies was significantly greater in the severely IgA-deficient group in comparison with the partially IgA-deficient group and the adult controls (chi-square test, P less than 0.01 and P less than 0.005, respectively). There was a strong correlation within each IgG subclass between antibody responses toward each of the three IgA antigens. Twenty-four children were followed over a period ranging from 0.9 to 11 years (mean, 2.3 years). Three children who were initially IgG anti-IgA antibody negative became antibody positive and three who were antibody positive became antibody negative. Five children with severe IgA deficiency remained severely IgA deficient and IgG antibodies to IgA persisted in all five at follow-up. The presence of IgG anti-IgA antibodies did not influence the normalization of serum IgA at follow-up in 14 of 19 children who were initially partially IgA deficient.

Human-isotype-specific enzyme immunoassay for antibodies to pneumococcal polysaccharides.

A simple enzyme immunoassay has been developed to allow the quantitation of the human response to immunization with pneumococcal polysaccharide. The assay uses the 14-valent vaccine (Pneumovax) as a convenient antigen to adsorb to the solid-phase microdilution plate wells and commercially available isotype-specific antibody conjugates. The results have been expressed as arbitrary pneumococcal polysaccharide antibody units by reading off a standard curve constructed by using heterogeneous pooled serum. All nonimmunized subjects tested had immunoglobulin G (IgG) antibodies present in serum. All six control subjects who were immunized with Pneumovax demonstrated an IgG response, and the majority responded with a rise in IgA- and IgM-specific antibody concentrations at a mean of 6 weeks postimmunization. Five out of six cord sera tested contained IgG antibodies only, which were present in concentrations similar to those seen in adults, whereas in 6- to 12-month-old infants only low levels of IgG and IgM and no IgA antibodies were detected. Serum taken from 10 hypogammaglobulinemic patients immediately prior to infusion of immunoglobulin showed low to negative IgG antibody concentrations, and no IgA or IgM antibody was present.

A human complement-fixing monoclonal anti-human lymphocyte antibody of rat origin.

MARCH 1E11 is an IgM monoclonal anti-human lymphocyte antibody of rat origin with the capacity to utilise both human and rabbit complement. The antibody reacts with all thymocytes and with all peripheral blood T and B lymphocytes. The treatment of human bone marrow or human peripheral blood mononuclear cells (PBMC) with MARCH 1E11 and either pooled human serum or autologous serum as a complement source resulted in cytolysis of greater than 99% of OKT3-positive lymphocytes. Under these conditions, progenitor cell recovery (colony-forming unit (CFU-c), burst forming unit--erythroid (BFU-e) and colony-forming unit--mixed (CFU-mix)) was greater than 90% of that of untreated cells. The response of treated marrow or PBMC to phytohaemagglutinin stimulation and in mixed leucocyte reactions demonstrated a reduction in thymidine incorporation to values similar to those obtained for unstimulated cells. The antibody does not cause modulation of the cell surface antigen and does not react significantly with non-lymphoid tissues. This monoclonal antibody may be useful for in vitro elimination of T lymphocytes from allogeneic bone marrow used for transplantation. The antibody may also be useful for treatment protocols requiring lymphoid depletion or immunosuppression as in organ transplantation.

Immunological reconstitution in a patient with severe combined immune deficiency using non-sibling bone marrow depleted of T cells with HuLy-m1.

An infant with severe immune deficiency received bone marrow from an HLA-A, -B, -DR matched, mixed leucocyte reaction non-reactive first cousin. The donor marrow was fractionated on a discontinuous Percoll gradient and before infusion was treated with the anti-human T lymphocyte antibody, HuLy-m1, and rabbit serum as a source of complement. Methotrexate was given during the following two weeks. A rise in the peripheral blood lymphocyte count, indicating engraftment, occurred six weeks after transplantation. There was no clinical evidence of graft versus host disease (GVHD). Engraftment has been sustained for one year and the patient is in normal health and has normal in vitro immunological function. In vitro treatment of human marrow with HuLy-m1 allows stable engraftment and may be useful in attempting to diminish or prevent GVHD.

Differentiated HL60 promyelocytic leukaemia cells have a deficient myeloperoxidase/halide killing system.

Following induction of differentiation by incubation with 1.25% dimethylsulfoxide (DMSO), cells of the HL60 promyelocytic leukaemia cell line acquire certain characteristics of the mature polymorphonuclear leucocyte (PMN) including the ability to produce oxygen radicals and to phagocytose opsonized bacteria. However, these cells are unable to fix 125I during phagocytosis and are only able to kill phagocytosed microorganisms (C. albicans and S. aureus) to a small degree compared to mature PMN. Further, release of myeloperoxidase (MPO) from cytoplasmic granules occurs to approximately 20% of control levels after 6 days culture with DMSO, and drops to negligible levels by 7 days. These data suggest an immature or inactive MPO/peroxide/halide killing system. Insensitivity to the cyclooxygenase pathway inhibitor indomethacin suggests that there may also be a defect in this pathway.

CFU-c enrichment from human bone marrow using a discontinuous Percoll gradient and soybean agglutinin in comparison with Ficoll-paque.

This study compares the efficiency of different methods of separation of human bone marrow in vitro prior to transplantation. Separation on Ficoll-paque resulted in a median recovery of 11.3 X 10(4) CFU-c/10(9) nucleated cells harvested. The recovery from the major CFU-c containing fraction following separation on a discontinuous Percoll gradient was 10.8 X 10(4) CFU-c/10(9) nucleated cells. The CFU-c recovered from Percoll were contained in a smaller number of cells, resulting in enrichment for CFU-c of 1.6 times that of Ficoll-paque. Further CFU-c enrichment to approximately three times that of Ficoll-paque separation was possible by treatment of Percoll fractionated cells with soybean agglutinin (SBA). However this caused an overall loss of 67% of CFU-c. Cells remaining after SBA treatment of the CFU-c containing Percoll fraction had increased spontaneous DNA synthesis and decreased PHA responses. There was no significant change in the mixed lymphocyte reaction in comparison with Ficoll-paque.

A quantitative ELISA for IgG in cell culture supernatants.

The measurement of IgG, using a sandwich-type enzyme-linked immunosorbent assay (ELISA), is described. The assay is specific, sensitive, and simple to perform. Purification of the antibody, prior to attachment to the plastic solid phase, results in a more sensitive test. Optimum standardisation of the reagents and conditions is described and discussed. The assay is capable of detecting IgG to 2.5 X 10(-5) IU/ml (approximately equal to 3 ng/ml) and is useful for measuring IgG produced by cells in culture. The coefficient of variation within assays is 6.0% and between assays is 7.7%.

A simple micro-assay for neutrophil bactericidal activity.

A micro-titre assay of neutrophil intracellular bactericidal activity is presented which requires only a relatively small number of cells and which is simple to perform, making it suitable for use in a clinical situation.

Hemophagocytic reticulosis. A case report with investigations of immune and white cell function.

A 5-month-old child with hemophagocytic reticulosis is described. Investigations revealed a grossly defective PHA response of the patient's lymphocytes which improved with chemotherapy. Defective glucose oxidation by phagocytosing cells and low IgA levels were demonstrated at diagnosis and have persisted despite chemotherapy. HL-A typing and chromosome studies did not reveal maternal lymphocytes in the child's circulation. The patient was treated with vinblastine and prednisolone and remains well after 11 months of treatment.