A scFv antibody fragment as a therapeutic candidate to neutralize a broad diversity of human IFN-alpha subtypes.

Despite their significant role in maintaining the normal physiology, cytokines may cause pathological conditions when they are overproduced. In this way, the increased expression of human interferon alpha (hIFN-alpha) is associated with acute viral infections, inflammatory disorders and several autoimmune illnesses, where the cytokine may be a factor in either initiating or maintaining the disease. Currently, there are several mAbs marketed for a variety of indications and many more in clinical trials, in which IFN-alpha represents a potential target for antibody-based therapy. A panel of 11 murine mAbs was prepared using recombinant hIFN-alpha2b as immunogen, all of which bound to the native form of the cytokine with affinity constants ranging from 1.7x10(7) M(-1) to 1.4x10(10) M(-1). An epitope mapping protocol demonstrated four spatially distinct areas of the protein recognized by the mAbs. Taking into account the characterization of the antibodies and their ability to inhibit the IFN-alpha biological activity, four mAbs were selected to produce scFv fragments. One of these fragments (CA5E6) was able to neutralize a wide spectrum of subtypes of the IFN-alpha family, including the recombinant cytokines hIFN-alpha2a and hIFN-alpha2b and a heterogeneous collection of IFN-alpha produced by activated leukocytes and Namalwa cells. With the aim of improving the affinity of the selected fragment, a standard error-prone PCR method was carried out. By using this strategy, it was possible to generate a new fragment (EP18) with increased affinity and ability to neutralize a broad diversity of IFN-alpha subtypes. Consequently, the scFv EP18 represents a potential therapeutic agent for those immune and inflammatory diseases which are associated with an increased IFN-alpha expression.

Augmentation and repair tissue formation of the nucleus pulposus after partial nucleotomy in a rabbit model.

Disc degeneration alters disc height and mechanics of the spinal column and is associated with lower back pain. In preclinical studies gel-like materials or resorbable polymer-based implants are frequently used to rebuild the nucleus pulposus, aiming at tissue regeneration and restoration of tissue function. To compare the outcome of tissue repair, freeze-dried resorbable polyglycolic acid-hyaluronan (PGA/HA) implants without any bioactive components or bioactivated fibrin (fibrin-serum) was used in a degenerated disc disease model in New Zealand white rabbits. Animals with partial nucleotomy only served as controls. The T2-weighted/fat suppression sequence signal intensity in the nuclear region of operated discs as assessed by magnet resonance imaging was reduced in operated compared to healthy discs, indicating loss of water and did not change from week 1 to month 6 after surgery. Quantification of histological and immunohistochemical staining indicated that the implantation of PGA/HA leads to significantly more repair tissue compared to nucleotomy only. Type II collagen content of the repair tissue formed after PGA/HA or fibrin-serum treatment is significantly increased compared to controls with nucleotomy only. The data indicate that intervertebral disc augmentation after nucleotomy has a positive effect on repair tissue formation and type II collagen deposition as shown in the rabbit model.

Skin disease is prevented but nephritis is accelerated by multiple pregnancies in autoimmune MRL/LPR mice.

The role of pregnancy in the progression of systemic lupus erythematosus (SLE) is still poorly understood. We analysed the effect of repeated pregnancies in MRL/lpr mice, a murine model of SLE. Seven-week old female mice were used: multiparous mice underwent three consecutive pregnancies (M); age-matched virgin mice served as controls (V). Animals were harvested at 20 weeks of age. Skin lesions were characterized by hair loss and scabs in the dorsum of the neck. Virgin skins showed thickened dermis, fibrosis and mononuclear cell infiltrates, which were practically absent in M. This was accompanied by higher IFN-gamma and lower IL-10 mRNA expression levels in V compared to M skin. Plasma IFN-gamma protein levels were also upregulated in V versus M. However, survival and kidney function were dramatically reduced and accompanied by hypertension after multiple pregnancies. Kidney histology also showed markedly increased renal lesions in M. In contrast to plasma and skin levels, both IL-10 and IFN-gamma mRNA were lower in the kidneys of V versus M mice. Concluding our findings, the pathomechanisms of lupus kidney and skin disease may be regulated differently at the organ level during pregnancy. Both IFN-gamma and IL-10 may be important regulatory cytokines at the local level.