Detection of Antibodies to Chlamydia trachomatis With Peptide-Based Species-Specific Enzyme Immunoassay

Objective: We have evaluated the sensitivity and specificity of a new synthetic peptide-based species-specific enzyme immunoassay (EIA) for detection of Chlamydia trachomatis IgG and IgA antibodies

Synthetic peptides as probes for protein interactions and as antigenic epitopes

In this study synthetic peptides have been used both as antigens in immunological studies, as well as probes in a study of protein interactions. Rabbit antibodies to the synthetic peptide sp23 derived from a cloned sequence of human endogenous retroviral gene erv-1 were used in a search for the expression products in human cell cultures and tissues. The cross-reactivity of the anti-peptide antibodies led to the detection of a novel protein from human chorio-carcinoma cell line. This protein of Mr 75 000 was purified by using conventional biochemical methods and the purification steps were monitored with anti-sp23 antibodies. Synthetic peptide deduced from the cDNA sequence of the transmembrane protein gp41 of human immunodeficiency virus HIV-1, the causative agent of AIDS, have been used as antigen detecting human antibodies to HIV-1. In clinical studies, strong antibody responses against this peptide were found during the early stages of HIV infection, including cases with seroconversion. The antibody level tended to decrease in the sera at the ARC and AIDS stages of HIV infection. Human antibodies to a synthetic peptide containing this sequence were affinity-purified and tested using various immunological methods. These affinity-purified antibodies did not react with the gp41 protein, suggesting that this epitope is partially or totally buried in the molecule and may only be exposed during antigen processing in vivo in the HIV-infected individuals. Laminin is a 1000 kd extracellular matrix protein, that has a multidomain structure with various functions such as neuronal cell-adhesion and the promotion of brain development and neurite outgrowth. In studies to locate functional regions in laminin molecule, synthetic peptides have been used in biological studies in vitro. A synthetic peptide derived from the maximally amphipathic region in the carboxy terminal part of B2 chain of laminin showed neurite outgrowth-promoting activity in neuronal cell cultures

Native and Complexed IGF-1: Biodistribution and Pharmacokinetics in Infantile Neuronal Ceroid Lipofuscinosis

Infantile neuronal ceroid lipofuscinosis (INCL) is a severe neurodegenerative disorder of childhood characterized by selective death of cortical neurons. Insulin-like growth factor 1 (IGF-1) is important in embryonic development and is considered as a potential therapeutic agent for several disorders of peripheral and central nervous systems. In circulation IGF-1 is mainly bound to its carrier protein IGFBP-3. As a therapeutic agent IGF-1 has shown to be more active as free than complexed form. However, this may cause side effects during the prolonged treatment. In addition to IGFBP-3 the bioavailability of IGF-1 can be modulated by using mesoporous silicon nanoparticles (NPs) which are optimal carriers for sustained release of unstable peptide hormones like IGF-1. In this study we compared biodistribution, pharmacokinetics, and bioavailability of radiolabeled free IGF-1, IGF-1/IGFBP-3, and IGF-1/NP complexes in a Cln1-/- knockout mouse model. IGF-1/NP was mainly accumulated in liver and spleen in all studied time points, whereas minor and more constant amounts were measured in other organs compared to free IGF-1 or IGF-1/IGFBP-3. Also concentration of IGF-1/NP in blood was relatively high and stable during studied time points suggesting continuous release of IGF-1 from the particles

Polyamine-regulated unproductive splicing and translation of spermidine/spermine N(1)-acetyltransferase

Spermidine/spermine N(1)-acetyltransferase (SSAT), the rate-controlling enzyme in the interconversion of spermidine and spermine, is regulated by polyamines and their analogs at many levels of gene expression. Recently, SSAT pre-mRNA has been shown to undergo alternative splicing by inclusion of an exon that contains premature termination codons. In the present study, we show that alterations in the intracellular polyamine level resulted in a change in the relative abundance of SSAT transcripts. Addition of polyamines or their N-diethylated analogs reduced the amount of the variant transcript, whereas polyamine depletion by 2-difluoromethylornithine or MG-132 enhanced the exon inclusion. Experiments performed with protein synthesis inhibitors and siRNA-mediated down-regulation of Upf1 protein verified that the variant transcript was degraded by nonsense-mediated mRNA decay (NMD). Interestingly, several proteins have been shown to regulate their expression by alternative splicing-coupled NMD, termed regulated unproductive splicing and translation (RUST). Our present results suggest that in the case of SSAT, RUST is mediated by polyamines, and this system functions to fine-tune the polyamine metabolism

The effect of peptides on the proteolytic cleavage of different protein substrates by PSA.

<p>(A) Peptide B2 enhanced the activity of PSA towards all protein substrates more strongly than C4, except for fibronectin this could not be detected. The peptides were preincubated with 0.2 µM PSA for 30 min prior to addition of 0.3–2.5 µM protein substrates and the cleavage of the proteins was detected after 10 min (semenogelin I), 40 min (semenogelin II), 4 h (fibronectin and nidogen-1) and 20–22 h (galectin-3 and IGFBP-3) incubation at 37°C. The notation 5* indicates that 5 µg of either peptide (with semenogelins I and II peptide C4, and with the other proteins B2) was added to the control sample. (B) Concentration of intact IGFBP-3 after incubation with PSA and peptides shown in relation to IGFBP-3 control without added PSA as measured by immunofluorometric assay that recognizes only intact, not cleaved IGFBP-3 (n = 2, mean ± SD).</p