[Aucubin combined with ADSCs-exos protects TBHP-induced nucleus pulposus cells via TLR4/NF-κB pathway]

This paper aims to investigate the effects and mechanisms of adipose-derived stem cells-exosomes(ADSCs-exos) toge-ther with aucubin in protecting human-derived nucleus pulposus cells(NPCs) from inflammatory injury, senescence, and apoptosis. The tert-butyl hydroperoxide(TBHP)-induced NPCs were assigned into normal, model, aucubin, ADSCs-exos, and aucubin+ADSCs-exos groups. The cell viability was examined by cell counting kit-8(CCK-8), cell proliferation by EdU staining, cell senescence by senescence-associated-β-galactosidase(SA-β-Gal), and cell cycle and apoptosis by flow cytometry. Enzyme-linked immunosorbent assay was employed to examine the expression of interleukin-1β(IL-1β), IL-10, and tumor necrosis factor-α(TNF-α). Real-time fluorescence quantitative PCR and Western blot were employed to determine the mRNA and protein levels of aggregated proteoglycan(aggrecan), type Ⅱ collagen alpha 1(COL2A1), Toll-like receptor 4(TLR4), and nuclear factor-kappa B(NF-κB). The results showed that compared with the model group, the aucubin or ADSCs-exos group showed enhanced viability and proliferation of NPCs, decreased proportion of G_0/G_1 phase cells, increased proportion of S phase cells, reduced apoptosis and proportion of cells in senescence, lowered IL-1β and TNF-α levels, elevated IL-10 level, down-regulated mRNA and protein levels of TLR4 and NF-κB, and up-regulated mRNA and protein levels of aggrecan and COL2A1. Compared with the aucubin or ADSCs-exos group, the aucubin+ADSCs-exos combination further increased the viability and proliferation of NPCs, decreased the proportion of G_0/G_1 phase cells, increased the proportion of S phase cells, reduced the apoptosis and proportion of cells in senescence, lowered the IL-1β and TNF-α levels, elevated the IL-10 level, down-regulated the mRNA and protein levels of TLR4 and NF-κB, and up-regulated the mRNA and protein levels of aggrecan and COL2A1. In summary, both aucubin and ADSCs-exos could exert protective effects by inhibiting inflammatory responses, reducing apoptosis and senescence of NPCs, improving cell viability and proliferation as well as extracellular matrix synthesis, which may be associated with the inhibition of TLR4/NF-κB signaling pathway activation. The combination of both plays a synergistic role in the protective effects.

Peptides for inducing cross-reactive anti-malarial antibodies

Immunological cross-reactions between malarial proteins are frequently observed. This paper describes an approach to generate such antibody responses that target many parasite proteins using a limited number of peptides as immunogens. Peptides used contained a known epitope, NKND, that is common to many malarial proteins or combinations of tri-peptides which are commonly present in parasite proteins. One of the two NKND-containing peptides elicited antibodies reacting to six parasite proteins and fusion proteins containing NKND. The antibody specificity was directed to NKND. Two of the four combination peptides were recognized by hyperimmune human sera and mouse immune serum in vitro, and one elicited antibodies recognizing parasites on immunofluorescence assay.

Identification of a common Plasmodium epitope (CPE) recognised by a pan-specific inhibitory monoclonal antibody

A Plasmodium falciparum genomic expression library was screened with a monoclonal antibody produced from mice infected with Plasmodium yoelii. Eleven unique clones were isolated all of which contained the sequence NKND, IKND or KKND. This sequence was confirmed as the epitope of M26-32 by testing a series of overlapping peptides and the allowable substitutions determined by testing the binding of M26-32 to peptides containing all possible single amino acid replacements of NKND. Potential epitopes of M26-32 occur in many plasmodial proteins and this is consistent with the large number of proteins recognised in these parasites by Western blotting. Since this monoclonal antibody shows marked in vitro inhibition of P. falciparum growth, these data suggest that an anti-malarial vaccine may be produced by targeting such common plasmodial epitopes without necessarily identifying the corresponding antigens.

Identification of anti-human IgG monoclonal antibodies and monoclonal antibodies with confined subclass reactivity

In a previous paper, 4 hybridoma cell lines (1B3, 2D5, 2A4 and 2B6) secreting antibodies against heavy chain of human IgG were reported. In this paper a more detailed study of these McAbs was introduced. First of all they were studied with double immunodiffusion test in agarose and it was demonstrated that they were reactive against 3 distinct antigenic determinants of human IgG. This result was also confirmed by ELISA competition test. These McAbs were further analysed for human IgG subclass proteins and it was found that 1B3 McAb gave positive reaction with all subclasses of IgG while the other 3 possessed confined subclass reactivity, i.e. McAb 2A4 did not react with IgG3 (called non-IgG3 McAb), and both McAbs 2D5 and 2B6 did not react with IgG4 (called non-IgG4 McAb). By agarose immunodiffusion test it was shown that: (i) Only transparent precipitation line was formed when McAb reacted with IgG antigen, however, in agarose containing 2% PEG-6000, the transparent precipitation line becomes opaque; (ii) When a mixture of two McAbs against the same antigenic determinants (2D5 and 2B6) was placed into the same well, the precipitation line remained transparent, but if they were not identical (2A4 and 2D5), then opaque precipitation line formed even in the absence of PEG. It was suggested that this phenomenon should be used for preliminary analysis for the identity among McAbs. The confined IgG subclass McAb may be used for the preparation and purification of IgG3 or IgG4 protein before specific McAb against IgG3 or IgG4 is obtained.(ABSTRACT TRUNCATED AT 250 WORDS)