Virus-specific CD4+ and CD8+ cytotoxic T-cell responses and long-term T-cell memory in individuals vaccinated against polio

The presence of poliovirus (PV)-specific CD4(+) T cells in individuals vaccinated against polio has been shown, but CD8(+) T-cell responses have not been described. Here, we functionally characterize the CD4(+) T-cell response and show for the first time that dendritic cells and macrophages can stimulate PV-specific CD8(+) T-cell responses in vitro from vaccinees. Both CD4(+) T and CD8(+) T cells secrete gamma interferon in response to PV antigens and are cytotoxic via the perforin/granzyme B-mediated pathway. Furthermore, the T cells also recognize and kill Sabin 1 vaccine-infected targets. The macrophage-stimulated CD4(+) T and CD8(+) T cells most likely represent memory T cells that persist for long periods in vaccinated individuals. Thus, immunity to PV vaccination involves not only an effective neutralizing antibody titer but also long-term CD4(+) and CD8(+) cytotoxic T-cell responses.     

Laminin-411 is a vascular ligand for MCAM and facilitates TH17 cell entry into the CNS

TH17 cells enter tissues to facilitate pathogenic autoimmune responses, including multiple sclerosis (MS). However, the adhesion molecules involved in the unique migratory capacity of TH17 cells, into both inflamed and uninflamed tissues remain unclear. Herein, we characterize MCAM (CD146) as an adhesion molecule that defines human TH17 cells in the circulation; following in vitro restimulation of human memory T cells, nearly all of the capacity to secrete IL-17 is contained within the population of cells expressing MCAM. Furthermore, we identify the MCAM ligand as laminin 411, an isoform of laminin expressed within the vascular endothelial basement membranes under inflammatory as well as homeotstatic conditions. Purified MCAM-Fc binds to laminin 411 with an affinity of 27 nM, and recognizes vascular basement membranes in mouse and human tissue. MCAM-Fc binding was undetectable in tissue from mice with targeted deletion of laminin 411, indicating that laminin 411 is a major tissue ligand for MCAM. An anti-MCAM monoclonal antibody, selected for inhibition of laminin binding, as well as soluble MCAM-Fc, inhibited T cell adhesion to laminin 411 in vitro. When administered in vivo, the antibody reduced TH17 cell infiltration into the CNS and ameliorated disease in an animal model of MS. Our data suggest that MCAM and laminin 411 interact to facilitate TH17 cell entry into tissues and promote inflammation.     

Natal homing in juvenile loggerhead turtles (Caretta caretta)

Juvenile loggerhead turtles (Caretta caretta) from West Atlantic nesting beaches occupy oceanic (pelagic) habitats in the eastern Atlantic and Mediterranean, whereas larger juvenile turtles occupy shallow (neritic) habitats along the continental coastline of North America. Hence the switch from oceanic to neritic stage can involve a trans-oceanic migration. Several researchers have suggested that at the end of the oceanic phase, juveniles are homing to feeding habitats in the vicinity of their natal rookery. To test the hypothesis of juvenile homing behaviour, we surveyed 10 juvenile feeding zones across the eastern USA with mitochondrial DNA control region sequences (N = 1437) and compared these samples to potential source (nesting) populations in the Atlantic Ocean and Mediterranean Sea (N = 465). The results indicated a shallow, but significant, population structure of neritic juveniles (PhiST = 0.0088, P = 0.016), and haplotype frequency differences were significantly correlated between coastal feeding populations and adjacent nesting populations (Mantel test R2 = 0.52, P = 0.001). Mixed stock analyses (using a Bayesian algorithm) indicated that juveniles occurred at elevated frequency in the vicinity of their natal rookery. Hence, all lines of evidence supported the hypothesis of juvenile homing in loggerhead turtles. While not as precise as the homing of breeding adults, this behaviour nonetheless places juvenile turtles in the vicinity of their natal nesting colonies. Some of the coastal hazards that affect declining nesting populations may also affect the next generation of turtles feeding in nearby habitats.     

The inhibitory effect of a herbal formula comprising ginseng and carthamus tinctorius on breast cancer

A compound (Zhu-xiang) from herbal extracts containing ginseng and carthamus tinctorius was used to treat the MDA-MB-231 breast cancer cell and normal human mammary gland cell lines. The inhibition of cell proliferation by Zhu-xiang, epirubicin, 5-fluorouracil and cyclophosphamide was determined by WST-1 assays. The apoptotic effect was studied by flow cytometry analysis of DNA strand breaks and ApopTag Peroxidase In Situ Apoptosis kit by the TUNEL assay. The proliferation index as well as cell cycle progression were also evaluated by flow cytometry using Ki-67 and propidium iodide respectively as markers. The Zhu-xiang showed significantly inhibition in cell proliferation and the inhibition was dose dependent. The inhibitory effect of Zhu-xiang was significantly greater than commonly used cytotoxic drugs. The inhibitory effect is a result of the induction of apoptosis, which is concentration- and time-dependent. DNA histograms indicate that the compound causes accumulation of cells mainly in the S phase. The viability of cells in breast solid tumours was measured by ATP bioluminescence assay to determine the drug-induced cytotoxicity of Zhu-xiang. The three different concentrations of Zhu-xiang all exhibited the ability to inhibit proliferation in solid tumour. Zhu-xiang could be a useful anti-cancer compound against breast cancer.     

Patterns of nuclease protection during strand exchange. recA protein forms heteroduplex DNA by binding to strands of the same polarity

recA protein, in the presence of ATP, polymerizes on single-stranded DNA (plus strand) to form a presynaptic nucleoprotein filament that pairs with linear duplex DNA and actively displaces the plus strand from the recipient molecule in a polarized fashion to form a new heteroduplex molecule. The interaction between recA protein and DNA during strand exchange was studied by labeling different strands and probing the intermediate with pancreatic deoxyribonuclease I (DNase I) or restriction endonuclease. The incoming single strand was resistant to DNase I in the original nucleoprotein filament and remained resistant even after extensive strand exchange had occurred. Both strands of the parental duplex molecule were sensitive to DNase I in the absence of joint molecule formation; but as strand exchange progressed following homologous pairing, increasing stretches of the parental plus strand became resistant, whereas the complementary parental minus strand remained sensitive to DNase I throughout the reaction. Except for a region of 50-100 base pairs at the end of the newly formed heteroduplex DNA where strand exchange was initiated, the rest of the heteroduplex region was resistant to cleavage by restriction endonucleases. The data suggest that recA protein promotes strand exchange by binding both the incoming and outgoing strands of the same polarity, whereas the complementary strand, which must switch pairing partners, is unhindered by direct contact with the protein.     

Induction of heat shock proteins in differentiated human and rodent neurons by celastrol

Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis have been termed protein misfolding disorders that are characterized by the neuronal accumulation of protein aggregates. Manipulation of the cellular stress-response involving induction of heat shock proteins (Hsps) in differentiated neurons offers a therapeutic strategy to counter conformational changes in neuronal proteins that trigger pathogenic cascades resulting in neurodegenerative diseases. Hsps are protein repair agents that provide a line of defense against misfolded, aggregation-prone proteins. These proteins are not induced in differentiated neurons by conventional heat shock. We have found that celastrol, a quinine methide triterpene, induced expression of a wider set of Hsps, including Hsp70B', in differentiated human neurons grown in tissue culture compared to cultured rodent neuronal cells. Hence the beneficial effect of celastrol against human neurodegenerative diseases may exceed its potential in rodent models of these diseases.