Peripheral Vγ9Vδ2 T Cells Are a Novel Reservoir of Latent HIV Infection

Eradication of HIV infection will require the identification of all cellular reservoirs that harbor latent infection. Despite low or lack of CD4 receptor expression on Vδ2 T cells, infection of these cells has previously been reported. We found that upregulation of the CD4 receptor may render primary Vδ2 cells target for HIV infection in vitro and we propose that HIV-induced immune activation may allow infection of γδ T cells in vivo. We assessed the presence of latent HIV infection by measurements of DNA and outgrowth assays within Vδ2 cells in 18 aviremic patients on long-standing antiretroviral therapy. In 14 patients we recovered latent but replication-competent HIV from highly purified Vδ2 cells demonstrating that peripheral Vδ2 T cells are a previously unrecognized reservoir in which latent HIV infection is unexpectedly frequent.     

The effect of carbon tetrachloride on isolated rat hepatocytes

Isolated rat hepatocytes were incubated with carbon tetrachloride (CCl4) at a concentration of 0.2 mol CCl4/ml of incubation medium. The ultrastructural alterations and release of lactate dehydrogenase (LDH) and glutamate-oxaloacetate transaminase (GOT), were recorded after different periods of incubation. After 5 min incubation with CCl4, morphological changes observed by electron microscopy, involved the plasma membrane. The endoplasmic reticulum and mitochondria were altered later. These morphological alterations were accompanied by an early release of LDH and GOT into the incubation medium. It is concluded that, in contrast with its in vivo effects, in vitro CCl4 can induced an early morphological alteration of the hepatocyte plasma membrane before damaging the endoplasmic reticulum.     

Latent HIV-1 infection of resting CD4⁺ T cells in the humanized Rag2⁻/⁻ γc⁻/⁻ mouse

Persistent human immunodeficiency virus type 1 (HIV-1) infection of resting CD4⁺ T cells, unaffected by antiretroviral therapy (ART), provides a long-lived reservoir of HIV infection. Therapies that target this viral reservoir are needed to eradicate HIV-1 infection. A small-animal model that recapitulates HIV-1 latency in resting CD4⁺ T cells may accelerate drug discovery and allow the rational design of nonhuman primate (NHP) or human studies. We report that in humanized Rag2^−/− γ_c^−/− (hu-Rag2^−/− γ_c^−/−) mice, as in humans, resting CD4⁺ T cell infection (RCI) can be quantitated in pooled samples of circulating cells and tissue reservoirs (e.g., lymph node, spleen, bone marrow) following HIV-1 infection with the CCR5-tropic JR-CSF strain and suppression of viremia by ART. Replication-competent virus was recovered from pooled resting CD4⁺ T cells in 7 of 16 mice, with a median frequency of 8 (range, 2 to 12) infected cells per million T cells, demonstrating that HIV-1 infection can persist despite ART in the resting CD4⁺ T cell reservoir of hu-Rag2^−/− γ_c^−/− mice. This model will allow rapid preliminary assessments of novel eradication approaches and combinatorial strategies that may be challenging to perform in the NHP model or in humans, as well as a rigorous analysis of the effect of these interventions in specific anatomical compartments.     

A locus conferring resistance to Colletotrichum higginsianum is shared by four geographically distinct Arabidopsis accessions

Colletotrichum higginsianum is a hemibiotrophic fungal pathogen that causes anthracnose disease on Arabidopsis and other crucifer hosts. By exploiting natural variation in Arabidopsis we identified a resistance locus that is shared by four geographically distinct accessions (Ws‐0, Kondara, Gifu‐2 and Can‐0). A combination of quantitative trait loci (QTL) and Mendelian mapping positioned this locus within the major recognition gene complex MRC‐J on chromosome 5 containing the Toll‐interleukin‐1 receptor/nucleotide‐binding site/leucine‐rich repeat (TIR‐NB‐LRR) genes RPS4 and RRS1 that confer dual resistance to C. higginsianum in Ws‐0 ( Narusaka et al., 2009 ). We find that the resistance shared by these diverse Arabidopsis accessions is expressed at an early stage of fungal invasion, at the level of appressorial penetration and establishment of intracellular biotrophic hyphae, and that this determines disease progression. Resistance is not associated with host hypersensitive cell death, an oxidative burst or callose deposition in epidermal cells but requires the defense regulator EDS1, highlighting new functions of TIR‐NB‐LRR genes and EDS1 in limiting early establishment of fungal biotrophy. While the Arabidopsis accession Ler‐0 is fully susceptible to C. higginsianum infection, Col‐0 displays intermediate resistance that also maps to MRC‐J. By analysis of null mutants of RPS4 and RRS1 in Col‐0 we show that these genes, individually, do not contribute strongly to C. higginsianum resistance but are both required for resistance to Pseudomonas syringae bacteria expressing the Type III effector, AvrRps4. We conclude that distinct allelic forms of RPS4 and RRS1 probably cooperate to confer resistance to different pathogens.     

The feasibility of non-viral gene transfer to the diaphragm in vivo

Gene transfer using electroporation is an essential method for the study of developmental biology, especially to understand the internal control of degeneration and apoptosis of the muscle cells that occurs earlier and quicker than the usual degeneration process occurring by aging. Such experimental studies may have a role in developing new strategies for treating patients suffering from inherited primary myopathies such as Duchenne muscular dystrophy (DMD). The present study was designed to evaluate the feasibility of electroporation mediated transfer of reporter genes to the diaphragm in vivo. This is the first report of gene transfer of naked plasmid DNA into the diaphragm muscle in vivo using electroporation. Our results showed that in vivo gene transfer of naked plasmid DNA into the diaphragm muscle using electroporation is feasible.