Placental isoferritin in pregnancies with small-for-gestational age fetuses

Placental immunomodulator ferritin, a novel immunoregulator, suppresses experimental arthritis

OBJECTIVE

To determine the effect of treatment with C48, the recombinant cytokine-like domain of the novel human placental immunomodulator ferritin (PLIF) immunoregulator, on zymosan-induced arthritis (ZIA) in mice and on adjuvant-induced arthritis (AIA) in rats.

METHODS

The in vitro effect of PLIF/C48 was tested in mixed lymphocyte cultures (MLCs) of allogeneic mouse splenocytes. Arthritis was induced by intraarticular injection of zymosan into naive mice and by subcutaneous injection of Mycobacterium tuberculosis into rats. C48 was injected intraperitoneally daily from day 3 to day 9 or from day 7 to day 13 after induction of synovitis by zymosan, and every other day from day 2 to day 14 after induction of AIA. Swelling of the joints and histologic features of the synovium were assessed. Th1 and Th2 cytokines were quantified by enzyme-linked immunosorbent assay.

RESULTS

Both PLIF and C48 significantly inhibited the in vitro immunoreactivity of mouse splenocytes in MLCs. Treatment of ZIA mice and AIA rats with C48 effectively reduced joint swelling. C48 treatment reduced synovial lining thickening, numbers of mononuclear cells and histiocytes, as well as cartilage destruction and bone erosions. In vitro, activated splenocytes from C48-treated ZIA and AIA animals produced significantly higher levels of interleukin-10 (IL-10). In animals with ZIA, this was accompanied by lower levels of tumor necrosis factor and IL-2.

CONCLUSION

Human PLIF and C48 were shown to exert cross-species immunosuppressive activity in vitro. The in vivo suppression of articular inflammation in the experimental models of ZIA and AIA was the result of treatment with the antiinflammatory human C48. These results suggest that treatment with C48 may offer an effective immunotherapeutic means of controlling inflammatory polyarthritis.

Construction and analysis of three-dimensional graphic model of single-chain Fv derived from an anti-human placental acidic isoferritin monoclonal antibody by computer

A three-dimensional (3D) graphic model of a single-chain Fv (scFv) which was derived from an anti-human placental acidic isoferritin (PAF) monoclonal antibody (MAb) was constructed by a homologous protein-predicting computer algorithm on Silicon graphic computer station. The structure, surface static electricity and hydrophobicity of scFv were investigated. Computer graphic modelling indicated that all regions of scFv including the inker, variable regions of the heavy (VH) and light (VL) chains were suitable. The VH region and the VL region were involved in composing the "hydrophobic pocket". The linker was drifted away VH and VL regions. The complementarity determining regions (CDRs) of VH and VL regions surrounded the "hydrophobic pocket". This study provides a theory basis for improving antibody affinity, investigating antibody structure and analyzing the functions of VH and VL regions in antibody activity.

Placental isoferritin levels in pregnant patients with systemic lupus erythematosus and/or antiphospholipid syndrome

PROBLEM

Low serum placental isoferritin (PLF), an immunosuppressive cytokine-like protein, was found in women with underlying placento-vascular dysfunction, such as intrauterine growth retardation and preeclamptic toxemia. The possible contribution of this placental product in the assessment of pregnant patients with either systemic lupus erythematosus (SLE) and/or antiphospholipid syndrome (APS) was investigated.

METHOD OF STUDY

Seventy-five healthy pregnant women used as controls and 25 preselected pregnant patients with either SLE and/or APS were enrolled in the study. Study patients were in remission during conception and all patients agreed to give 5 ml of venous blood at midgestation. The samples were frozen and analyzed retrospectively. After delivery, pregnancy outcomes were gathered from hospital records.

RESULTS

Seventeen (68%) women had uneventful pregnancies and deliveries (normal) whereas 8 (32%) showed pathologic obstetric outcomes. Mean midgestational serum PLF levels were similar in the control and normal outcome groups (87 U/ml), whereas significantly lower levels (37 U/ml) were measured in the pathologic outcome group. Using a cutoff level of 10 U/ml, 85% from the normal outcome group and 15% from the pathologic outcome group were above this threshold level, with 60% specificity and 100% sensitivity.

CONCLUSIONS

These preliminary data suggest that PLF values may reflect placento-vascular functions. These may represent a predictive biomarker for developing obstetric complications in pregnant women with either SLE and/or APS.

cDNA sequence analysis of monoclonal antibodies against the human placental acidic isoferritin

By using human placental acidic isoferritin (PAF) as antigen to immunize BALB/c mice and conventional cell fusion, we have established three mouse hybridoma cell lines that secrete IgG monoclonal antibodies (MAbs) to PAF, termed as Z-2-3, Z-2-5, and Z-3-6, respectively. In ELISA, the MAbs were shown to react specifically with human PAF. We then applied the polymerase chain reaction (PCR) technique to clone variable region genes of the heavy (V(H)) and light (V(L)) chains of these MAbs, and appropriate full-length cDNA clones were obtained and characterized by nucleotide sequence analysis. V(H) and V(L) segments of anti-human PAF MAbs belong to the J558 and Vkappa19 family, respectively. The nucleotide sequence of Z-3-6 in the V(H) segment is highly homologous to that of MAb 18.1.16 except for their diversity minigenes. The light chain sequences of these MAbs show high homology with that of MAb cc92. It is implied that the D segment and the nucleotides inserted at the V(H)-D and D-J splice junctions are mostly responsible for the specificity of Z-3-6, and that the differences between the V(H) and V(L) sequences of these MAbs may determine their different affinity or recognition of different antigenic determinants.