Effects of polyamines on proliferation and IgM productivity of human-human hybridoma, HB4C5 cells

Polyamines and hormesis: Making sense of a dose response dichotomy

The diverse biological effects of polyamines (putrescine, spermidine and spermine) were reviewed in the context of hormesis in an integrative manner for the first time. The findings illustrate that each of these polyamines commonly induces hormetic dose responses in a wide range of biological models and types of cells for multiple endpoints in numerous plant species and animal models. Plant research emphasized preconditioning experimental studies in which the respective polyamines conferred some protection against the damaging effects of a broad range of environmental stressors such as drought, salinity, cold/heat, heavy metals and UV-damage in an hormetic manner. Polyamine-based animal hormesis studies emphasized biomedical endpoints such as longevity and neuroprotection. These findings have important biological and biomedical implications and should guide experimental designs of low dose investigations.

New insights into the role of dietary spermine on inflammation, immune function and related-signalling molecules in the thymus and spleen of piglets

This study aimed to determine the effects of dietary spermine supplementation on the inflammatory response and immune function of the thymus and spleen in piglets. Eighty suckling piglets were randomly assigned to receive adequate nutrients supplemented with spermine (0.4 mmol/kg body weight) or restricted nutrient intake supplemented with normal saline for 7 h or 3, 6 and 9 days in pairs. Regardless of treatment time, spermine supplementation decreased (p < 0.05, compared with the controls) the following: (1) tumour necrosis factor α (TNF-α), interleukin (IL)-1β, 2 and 6, and interferon (IFN)-γ levels in serum; (2) gene expression of cluster of differentiation 8 and integrin beta-2 in the thymus and spleen and the lymphocyte function-associated antigen 1 in the thymus; (3) mRNA levels of TNF-α, IL 1β, 2, 6, and 12, IFN-γ and inducible nitric oxide synthase in the thymus and spleen, as well as IL-8 in the spleen; and (4) eukaryotic IF4E-binding protein 1, Janus kinase 2, signal transducer and activator of transcription 3, and nuclear factor-kappa B P65 gene transcriptions in the thymus and spleen. By contrast, spermine supplementation increased (p < 0.05) the following: (1) immunoglobulin M, IL-10, and transforming growth factor β1 gene expression, as well as (2) relative mRNA levels of mammalian target of rapamycin (mTOR) and ribosomal protein S6 kinase 1 in the thymus and spleen. These effects were also observed upon prolonged spermine administration (p < 0.05). In summary, dietary spermine supplementation can alleviate inflammatory response, enhance the immune function and regulate the gene expression of signalling molecules related to inflammation.

Rational development of a serum-free medium and fed-batch process for a GS-CHO cell line expressing recombinant antibody

A serum-free medium (CHO-SFM) together with a fed-batch process was developed for the cultivation of a recombinant GS-CHO cell line producing TNFR-Fc. According to the metabolic characteristics of GS-CHO cell, a basal medium was prepared by supplementing DMEM:F12:RPMI1640 (2:1:1) with amino acids, insulin, transferrin, Pluronic F68 and some other ingredients. Statistical optimization approaches based on Plackett-Burman and central composite designs were then adopted to identify additional positive determinants and determine their optimal concentrations, which resulted in the final CHO-SFM medium formulations. The maximum antibody titer reached was 90.95 mg/l in the developed CHO-SFM, which was a 18 % and 10 fold higher than that observed in the commercial EX-CELL™ 302 medium (76.95 mg/l) and basal medium (8.28 mg/l), respectively. Subsequently, a reliable, reproducible and robust fed-batch strategy was designed according to the offline measurement of glucose, giving a final antibody yield of 378 mg/l, which was a threefold improvement over that in conventional batch culture (122 mg/l) using CHO-SFM. In conclusion, the use of design of experiment (DoE) method facilitated the development of CHO-SFM medium and fed-batch process for the production of recombinant antibody using GS-CHO cells.

Immunostimulatory effects of collagen from jellyfish in vivo

We focused on the biological activity of the collagen extracts obtained from the giant edible jellyfish, Nemopilema nomurai. Jellyfish collagen extracts stimulates the production of immunoglobulins (Igs) and cytokines by human hybridoma cells and human peripheral blood lymphocytes. Therefore, we examined the immunoregulatory function of jellyfish collagen extracts in mice. Intake of jellyfish collagen extracts facilitated the Ig production activity of lymphocytes from spleen and Peyer's patch. Furthermore, the levels of Igs in the serum clearly increased after the administration of jellyfish collagen extracts. Intake of bovine collagen from Achilles' tendon also activated lymphocytes activity in mice. The activity of total and antigen-specific Ig production in splenocytes from OVA-challenged mice was also enhanced by collagen intake. However, the total and OVA-specific IgE levels in the serum were not affected by the collagen intake. These results suggested that jellyfish collagen extracts stimulates an immune response in vivo, without inducing allergic complications.

Identification of two aberrant transcripts derived from a hybridoma with amplification of functional immunoglobulin variable genes

Murine monoclonal antibodies (mAbs) are widely used but have limitations if administered in humans. The use of chimeric or humanized mAbs can reduce immunogenicity. The first step in producing such mAbs is to clone murine variable genes from a hybridoma, but it is possible to amplify both functional and aberrant variable genes, as they coexist in the hybridoma. During the development of a murine-human chimeric antibody, we have cloned from a hybridoma the functional heavy chain variable region (V(H)) and light chain variable region (V(L)) genes of a mAb that blocks the binding of anthrax lethal factor to protective antigen. In this study, we report the detection of two aberrant transcripts from a hybridoma produced using myeloma cell line OUR-1, the development of a method to distinguish between the functional and abundant aberrant V(L) transcripts, and the origins of these aberrant genes. The aberrant V(L) gene is derived from OUR-1 cells, while the aberrant V(H) gene might derive from antibody repertoires in B cells or from gene rearrangement in the hybridoma cells. The aberrant V(H) and V(L) genes in this study may facilitate discrimination between the functional and aberrant variable genes from hybridoma cells.