Recombinant human complement component C2 produced in a human cell line restores the classical complement pathway activity in-vitro: an alternative treatment for C2 deficiency diseases

Background: Complement C2 deficiency is the most common genetically determined complete complement deficiency and is associated with a number of diseases. Most prominent are the associations with recurrent serious infections in young children and the development of systemic lupus erythematosus (SLE) in adults. The links with these diseases reflect the important role complement C2 plays in both innate immunity and immune tolerance. Infusions with normal fresh frozen plasma for the treatment of associated disease have demonstrated therapeutic effects but so far protein replacement therapy has not been evaluated. Results: Human complement C2 was cloned and expressed in a mammalian cell line. The purity of recombinant human C2 (rhC2) was greater than 95% and it was characterized for stability and activity. It was sensitive to C1s cleavage and restored classical complement pathway activity in C2-deficient serum both in a complement activation ELISA and a hemolytic assay. Furthermore, rhC2 could increase C3 fragment deposition on the human pathogen Streptococcus pneumoniae in C2-deficient serum to levels equal to those with normal serum. Conclusions: Taken together these data suggest that recombinant human C2 can restore classical complement pathway activity and may serve as a potential therapeutic for recurring bacterial infections or SLE in C2-deficient patients

The genomic basis of parasitism in the Strongyloides clade of nematodes.

Soil-transmitted nematodes, including the Strongyloides genus, cause one of the most prevalent neglected tropical diseases. Here we compare the genomes of four Strongyloides species, including the human pathogen Strongyloides stercoralis, and their close relatives that are facultatively parasitic (Parastrongyloides trichosuri) and free-living (Rhabditophanes sp. KR3021). A significant paralogous expansion of key gene families--families encoding astacin-like and SCP/TAPS proteins--is associated with the evolution of parasitism in this clade. Exploiting the unique Strongyloides life cycle, we compare the transcriptomes of the parasitic and free-living stages and find that these same gene families are upregulated in the parasitic stages, underscoring their role in nematode parasitism

Distribution of 124I-labeled I2S following positron emission tomography in cynomolgus monkeys at 5 hours after injection (normalized^*).

<p>*Data normalized to 2 kg animal body weight.</p><p>**The total injected doses in the IV groups were 3.5±1 mg and 0.34±0.1 mg, respectively.</p><p>ICV, intracerebroventricular; ID, injected dose; IL, intralumbar; IV, intravenous.</p

Cellular uptake of I2S in IT-injected (three injections) I2S knockout mice.

<p>(<b>A</b>) I2S immunohistochemical staining of the cerebral cortex of untreated control mice was negative. In IT-injected mice, I2S positive staining was found in neurons of the cerebral cortex (<b>B</b>) and Purkinje cells of the cerebellum (<b>C</b>). Meningeal cells (arrows) were also I2S positive in IT-injected animals. Scale bar: 25 µm.</p

Design of I2S biodistribution study in cynomolgus monkeys.

<p>*I2S unless otherwise specified.</p><p>DC, device control; IT, intrathecal; IV, intravenous; NS, normal saline; PBS, phosphate-buffered saline, pH 7.2.</p

Widespread distribution in the brains of dogs following either intracerebroventricular (ICV) or intrathecal (IT) administration.

<p><b>(A)</b> I2S immunohistochemical staining of the cerebral cortex of vehicle control dogs was negative. Representative fluorescent immunohistochemical images showed uptake of I2S in the neurons of both ICV-dosed (<b>C,D,F,H</b>) and IT-dosed (<b>C,E,G,I</b>) dogs. I2S was detected in neurons in the deep internal layer of the cerebral cortex (<b>B,C</b>), Purkinje cells of the cerebellum (<b>D</b>,<b>E</b>) and neurons in the hippocampus (<b>F,G</b>) and thalamus (<b>H,I</b>). Green, I2S; blue, DAPI-stained nuclei. Scale bar: 25 µm.</p

Reversal of pathology in I2S knockout (mucopolysaccharidosis II) mice after three IT-lumbar injections of I2S.

<p>(<b>A</b>) Hematoxylin and eosin-stained brain tissues of uninjected (left panels) and injected (right panels) mice showed numerous cellular storage vacuoles (arrows) in the uninjected brain that were markedly reduced in injected mice in the cerebral cortex (<b>a,b</b>), caudate nucleus (<b>c,d</b>), thalamus (<b>e,f</b>), white matter (<b>g,h</b>), and cerebellum (<b>i,j</b>). Scale bar: 25 µm. (<b>B</b>) As demonstrated by immunohistochemical staining of lysosomal-associated membrane-1 (LAMP-1), there was a marked reduction of LAMP-1 immunoreactivity in the brains after three IT injections of I2S (right panels) compared with uninjected mice (left panels). There was a decrease in the number of LAMP-1 positive cells and lighter staining intensity in the cerebral cortex (<b>a,b</b>), caudate nucleus (<b>c,d</b>), thalamus (<b>e,f</b>), white matter (<b>g,h</b>), and cerebellum (<b>i,j</b>). Scale bar: 25 µm. <b>(C)</b> A comparison of the mean LAMP-1 positive area between uninjected and I2S (two or three IT injections) injected wild-type (WT) mice in the cerebral cortex (cortex), caudate nucleus (CP), thalamus (TH), white matter (WM) and cerebellum (CBL). Data are represented as the mean ± s.d. # P<0.05; * P<0.01; ** P<0.001.</p