Polymorphism detection of porcine PSMC3, PSMC6 and PSMD3 genes and their association with partial growth, carcass traits, meat quality and immune traits

PSMC3, PSMC6 and PSMD3 genes encode the proteasome 26S ATPase subunit 3, subunit 6 and the non-ATPase subunit 3, respectively, and exert the function in antigen processing and presentation. So these three genes were considered as the candidate genes that have the effect on porcine production and immune traits in this study. Genetic variations of these three genes were investigated and the single nucleotide polymorphism-based (SNPs-based) association analyses were studied initially. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) revealed that there is a MvaI polymorphic site in intron3 of PSMC3 gene and a MboI polymorphic site within intron 5 of PSMC6 gene, as well as a RsaI polymorphic site within exon 10 of the PSMD3 gene. χ2 analysis presented that allele frequencies differed among four breeds (Meishan, Erhualian, Qingping pig and Duroc) at PSMC3 and PSMD3 loci (P < 0.01). Association analysis showed that the PSMC3 gene has an effect on average backfat thickness (P < 0.01), total erythrocytes (P < 0.01) and hematocrit (P < 0.01), and there is a significant association between the PSMD3 genotypes and the mean corpuscular volume. PSMC6 has no effect on the production and immune traits we studied. Key words: Porcine, PSMC3, PSMC6, PSMD3, polymorphism, association analysis

Characterization of epitopes for neutralizing monoclonal antibodies to classical swine fever virus E2 and Erns using phage-displayed random peptide library

Infection of cells with classical swine fever virus (CSFV) is mediated by the interaction of envelope glycoproteins E2 and Erns with receptor molecules on the cell surface. These proteins are also the major antigens for eliciting neutralizing antibodies and conferring protective immunity. Here we report the identification of multiple neutralizing epitopes on these proteins by screening a phage-displayed random peptide library with CSFV-specific neutralizing monoclonal antibodies. Two different E2-specific neutralizing mAbs (a18 and 24/10) were found to bind to a common motif SPTxL, which is similar to the sequence SPTTL of the E2 protein (aa 289-293), indicating that this is likely to be an immunodominant epitope. Similarly, an immunodominant epitope corresponding to the sequence DKN of Erns (aa 117-119) was identified for two independent Erns-specific neutralizing antibodies, b4-22 and 24/16, respectively. Another binding motif, CxNNxTC, was identified for mAb 24/16, but not for b4-22. Sequencing analysis of the genes coding for the light chain of these mAbs was conducted to ensure that all mAbs were derived from different hybridomas, rather than from different subclones of a common parent line. Inhibition studies using immunofluorescent antibody assay and virus neutralization test demonstrated that the mimotope peptides truly mimicked the antibody binding determinants on the viral proteins. The detailed mapping data for these neutralizing epitopes will be useful for development of improved diagnostic tests and perhaps a peptide-based vaccine for this important swine disease.

Enhanced Maturation and Functional Capacity of Dendritic Cells Induced by Mannosylated L2 Domain of ErbB2 Receptor

The nature of antigens and functional state of dendritic cells (DC) are important in antigen presentation. The ability of DC for the induction of T-cell responses is promoted by maturation. It has been confirmed that mannose receptors mediate highly efficient endocytosis and presentation of mannosylated proteins. In the present study, L2 domain of ErbB2 ectodomain was expressed in Escherichia coli, purified and mannosylated. The maturation and functional capacity of DC induced by mannosylated L2 (mL2) protein were investigated. The results showed that L2 protein could induce DC maturation, which was accompanied by elevated expression of MHC and co-stimulatory molecules. The effect of mL2 protein on DC maturation was more remarkable than that of non-mL2 proteins. Uptake of mL2 antigens by DC was more efficient. Furthermore, the T cells can be stimulated to proliferate in vitro and secrete Th1 and Th2 cytokines. Higher levels of both IFN-gamma and IL-10 were detected from the T cells stimulated by mL2-pulsed DC, suggesting a concurrent activation of CD4+ and CD8+ T cells. The results demonstrated that L2 domain of ErbB2 receptor is an immunodominant molecule. The mL2 domain of ErbB2 can induce an enhanced maturation and functional capacity of DC. It may become an effective strategy to induce anti-ErbB2 response.

Quantum noise properties of parametric processes

In this paper the quantum noise properties of phase-insensitive and phase-sensitive parametric processes are studied. Formulas for the field-quadrature and photon-number means and variances are derived, for processes that involve arbitrary numbers of modes. These quantities determine the signal-to-noise ratios associated with the direct and homo-dyne detection of optical signals. The consequences of the aforementioned formulas are described for frequency conversion, amplification, monitoring, and transmission through sequences of attenuators and amplifiers.

Lack of EGF receptor contributes to drug sensitivity of human germline cells

Germline mutations have been associated with generation of various types of tumour. In this study, we investigated genetic alteration of germline tumours that affect the drug sensitivity of cells. Although all germline tumour cells we tested were hypersensitive to DNA-damaging drugs, no significant alteration was observed in their DNA repair activity or the expression of DNA repair proteins. In contrast, germline tumours expressed very low level of epidermal growth factor receptor (EGFR) compared to drug-resistant ovarian cancer cells. An immunohistochemical analysis indicated that most of the primary germline tumours we tested expressed very low level of EGFR. In accordance with this, overexpression of EGFR in germline tumour cells showed an increase in drug resistance, suggesting that a lack of EGFR, at least in part, contributes to the drug sensitivity of germline tumours.

Sequence characterization, polymorphism and chromosomal localizations of the porcine PSME1 and PSME2 genes

The full-length cDNA of porcine genes (PSME1 and PSME2) encoding proteasome activators PA28alpha- and beta-subunits were obtained by the rapid amplification of cDNA ends (RACE). The nucleotide sequences and the predicted protein sequences share high sequence identity with their mammalian counterparts. The reverse transcriptase-polymerase chain reaction (RT-PCR) revealed that porcine PSME1 and PSME2 genes are expressed in all eight tissues studied (liver, spleen, bladder, small intestine, kidney, heart, skeletal muscle and lung). The full-length genomic DNA of the porcine PSME1 and PSME2 genes were amplified by PCR. These two genes shared the same structure and were similar in size. A C/T single nucleotide polymorphism in PSME1 intron 8 detected as an SphI PCR-restriction fragment length polymorphism (PCR-RFLP) shows allele frequency differences between Meishan, Tibetan, Large White, Qingping, and Duroc pigs. The association analysis using two experimental GY selection lines selected for growth rate or leanness suggested that the PSME1 genotype was associated with weaning weight. Analyses of somatic cell hybrid (SCHP) and radiation hybrid (IMpRH) panels revealed that both genes map to SSC7q15.3-q21 and closely linked to the T-cell receptor alpha (TCRA) gene.

Retroviral delivery of GAD-IgG fusion construct induces tolerance and modulates diabetes: a role for CD4+ regulatory T cells and TGF-beta?

Previous studies have demonstrated that antigen-specific tolerance could be induced by lipopolysaccharide (LPS)-stimulated B cells retrovirally transduced with an immunoglobulin-antigen (or epitope-containing peptide) fusion construct. To investigate the mechanism of this gene therapy system, we now adapted this approach to immunotherapy of spontaneous diabetes in nonobese diabetic (NOD) mice, a T-cell-mediated autoimmune disease triggered, in part, by a pathogenic response to glutamate decarboxylase (GAD) 65. We demonstrate that LPS-stimulated splenocytes, retrovirally transfected with GAD-IgG fusion construct, induce a significant antigen-specific hyporesponsiveness at both cellular and humoral levels and reduce the incidence of diabetes in female NOD mice. Parallel with disease protection, we observed a prolonged increase of the numbers of CD4+CD25+ T cells in the periphery of GAD-IgG-treated mice, compared to those treated with a control IgG vector, both in the prediabetic period and persisting even 8 months after gene therapy. This increase appeared to be induced by the repeated stimulation of the antigen in the periphery instead of a result of differentiation of T-cell precursor in the thymus. Moreover, CD4+CD25+ T cells induced by GAD-IgG fusion construct were capable of suppressing the proliferative response of CD4+CD25- T cells in vitro; and ablation of the activity of CD4+CD25+ T cells by blocking antibody against CD25 could reverse GAD-specific T-cell hyporesponsiveness. These results suggested that CD4+CD25+ T-cell subset induced in GAD-IgG-treated NOD mice represented the regulatory or suppressive CD4+CD25+ T cells (Treg) and might play an important role in the induction and maintenance of tolerance in NOD mice. Furthermore, the numbers of splenic CD4+CD62L+ regulatory T cells in GAD-IgG-treated mice during the prediabetic period and serum TGF-beta levels in 34-38-week-old GAD-IgG-protected mice were also increased, compared to control IgG-treated ones. Therefore, we propose that the induction of tolerance and the prevention of diabetes incidence in NOD female mice induced by the GAD-IgG fusion construct may require CD4+ regulatory T cells, and the possible mediation of TGF-beta.

Therapeutic effects of dengue 2 virus capsid protein and staphylococcal nuclease fusion protein on dengue-infected cell cultures

Dengue infection poses a serious public health problem in most tropical and subtropical areas. No effective antiviral drugs or vaccines are currently available against dengue infection. To explore the feasibility of using capsid-targeted viral inactivation (CTVI) as an antiviral strategy against dengue infection, we constructed a plasmid expressing a fusion protein consisting of staphylococcal nuclease (SN) fused to dengue 2 virus capsid protein (D2C), and investigated its effects on the production of infectious virions when introduced into BHK cells infected with dengue virus. The results indicated that D2C-SN can be expressed and tolerated in this mammalian cell culture. The enzymatically active SN moiety was incorporated into nascent virions during the process of viral assembly. By comparing the effects of incorporated SN and SN*, an enzymatically inactive missense mutant form of wild-type SN, on the infectivity of progeny virions, we clearly demonstrated that nucleolytic activity was the major antiviral mechanism. Expression of D2C-SN fusion protein as a therapeutic agent resulted in a reduction in infectious titers of 12- to 60-fold. Therefore, dengue virus may be particularly vulnerable to a CTVI therapeutic approach.

Genetic diversity analyses of 10 indigenous Chinese pig populations based on 20 microsatellites

To study the genetic diversity of Chinese indigenous pig breeds, a total of 403 pigs from 10 local populations and 1 exotic Duroc breed were genotyped for 20 microsatellite markers. Heterozygosity and Wright's F-statistics (F(IS), F(ST), and F(IT)) were calculated to determine the genetic variation in those populations. The observed heterozygosities were in the range of 0.31 (Duroc) to 0.66 (Shengxian). The F(IS) value was in a range of -0.07 to 0.48. The mean F(ST) showed that approximately 78% of the genetic variation was within-population and 22% was across the populations. The 10 Chinese local breeds were classified into two major groups according to the phylogenetic tree, which was based on standard genetic distance. Four pig populations, Jianli, Ganxi Two Ends Black, Shaziling, and Dongshan were grouped into one branch. Before the study, these four populations were all classified as Central China Two Ends Black according to coat color, shape of the head, and shape of the ear. The Jinhua pig, which also has the two-ends-black coat color, was also grouped to the same branch but was not traditionally classified into this type. The five populations were located in various provinces in central China. The other five populations, Nanyang Black, Hainan Spotted, Huainan Black, Jiaxing Black, and Shengxian Spotted (black body, white feet), were grouped into another branch. The two groups of pig breeds had the same F(ST) value (0.14) when calculated separately. This value was similar to that of Iberian pigs (0.13) but smaller than that of the European pigs (0.27) as reported by other researchers. Our study showed that large genetic differentiation exists in Chinese pig breeds. The grouping of the five two-ends-black populations into one branch of the phylogenetic tree may indicate that the number of conservation farms can be decreased for this type of pig.