Lentiviral infections

Any alternative vector that allows a tetracycline-regulated expression of your shRNA can be used. Remember to consider the DNA delivery method (plasmid transfection or lentiviral transduction) to select the right vector. In the case of lentiviral infection, pLenti4/TO/V5-DEST (Invitrogen) could be another option. 

Darko DF, Mitler MM, Henriksen SJ. Lentiviral infection, immune response peptides and sleep. Adv Neuroimmunol 1995 5 57-77. 

Lentiviral infection Random, singlecopy integrations at multiple loci 1-10 (somewhat controllable by viral titer) Each founder is genetically unique Must breed multiple lines. Transgenes may segregate... 

Because many steps in lentiviral infection (reverse transcription, nuclear transport, and integration) depend on cellular cofactors (65, 66, 68-70), there may be serious limitations in the use of nonhuman lentiviral vectors in primary human tissues. Replication of lentivimses is highly adapted to their natural host, indicating that cross species variability of cellular factors essential for vims replication, and thus vector transduction, may impair the transduction efficiency of nonhuman lentiviral vectors in human cells. These restrictions may be overcome by the use of chimeric lentiviral vectors. Indeed, cross-packaging of FIVRNAby HIV-1 and SIV packaging systems has been demonstrated, and viral proteins were able to... 

Li MJ, Kim J, Li S, Zaia J, Yee JK, Anderson J, Akkina R, Rossi JJ (2005b) Long-term inhibition of HlV-1 infection in primary hematopoietic cells by lentiviral vector delivery of a triple combination of anti-HIV shRNA, anti-CCR5 ribozyme, and a nucleolar-localizing TAR decoy. Mol Ther 12 900-909... 

Qin XF, An DS, Chen ISY, Baltimore D (2003) Inhibiting HlV-1 infection in human T cells by lentiviral-mediated delivery of small interfering RNA against CCR5, Proc Natl Acad Sci USA 100 183-188... 

The use of vectors based on other primate lentiviruses (83,84) may also eliminate some of the concerns however, HIV-2 and simian immunodeficiency vims (SIV) are closely related to HI V-1. Therefore, vectors based on nonprimate lentiviruses like feline immunodeficiency virus (FIV), equine infectious anemia vims, and visna may be more acceptable (85-87). These viruses do not cause infection in humans due to restrictions in the envelope tropism. However, the risk associated with the introduction of nonhuman lentiviral vectors in human tissues is unknown, and the actual safety of these lentiviral vectors remains to be evaluated. 

Stable transfection or infection with lentiviral or retroviral vectors... 

Retroviral or lentiviral vectors are preferentially used for HIV-1 gene therapy studies. Two main strategies for gene therapy of HIV-1 infection have been used ... 

Esimone and coworkers, in their increasing study of West African lichen species, identified the utility of R. farinacea derivatives against lentiviruses and adenoviruses. Esimone et al. (2005) initially showed that the ethyl-acetate-soluble fraction ET4) from the lichen Ramalina farinacea inhibited the infectivity of lentiviral and adenoviral vectors, as well as wild-type HIV-1. Recorded antiviral activity was about 20 pg/ml. Preliminary mechanistic studies based on the addition of the extracts at different time points in the viral infection cycle (kinetic studies) led to the suggestion that early steps in the lentiviral or adenoviral replication cycle could be the major target of ET4. Inhibition of wild-type HIV-1 was also observed at a tenfold lower concentratiOTi of the extract. 

Lentiviruses can infect non-dividing cells, thereby allowing stable gene transfer in post-mitotic mature neurons. Lentiviral vector-mediated delivery of short hairpin RNAs (shRNAs) results in persistent knockdown of gene expression. In addition, inducible lentiviral vectors offer a powerful tool for better assessing the function of a gene candidate in targeted neurons by an on-off system [1]. 

The envelope glycoproteins of wild-type retroviruses and lentiviruses bind to cell surface receptors to facilitate entry of the vims into the cytoplasm where the viral RNA is reverse transcribed to form a cDNA, the proviras. This provirus is translocated to the nucleus where it integrates into the host cell chromosomes and through the normal process of DNA transcription encodes new viral proteins and new viral RNA, which are assembled at the cell surface into new viral particles. Replication-defective retroviral and lentiviral vectors infect cells by similar mechanisms, but unlike wild-type viruses, the integrated provirus from these vectors encodes the therapeutic gene and viral particles are not produced. 

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