Resting CD4+ T Cells with CD38+CD62L+ Produce Interleukin-4 Which Contributes to Enhanced Replication of T-Tropic Human Immunodeficiency Virus Type 1

AbstractA significant increase in the CD38+ population among T lymphocytes has been observed in human immunodeficiency virus type 1 (HIV-1)-infected carriers. We previously reported a higher replication rate of T-tropic HIV-1 in the CD4+CD38+CD62L+ than CD38− subset under conditions of mitogen stimulation after infection. Here, we revealed a similarly high susceptibility in the CD38+ subset on culture with conditioned medium containing Th2 cytokine, interleukin (IL)-4 that was produced endogenously from this subset on stimulation with mitogen or anti-CD3 antibody for 3 days. The contribution of IL-4 to the upregulated production of virus in the CD38+ subset was confirmed by culture of this subset with recombinant human IL-4. In contrast, the rate of replication in the CD38− subset was not augmented in the conditioned medium from either subset or with IL-4. However, there were no differences in the surface expression of IL-4 receptor or HIV-1 receptors CD4 and CXCR4 between the two subsets. Thus, the CD4+CD38+CD62L+ subset comprises a specific cell population secreting endogenous Th2 cytokine that contributes to the efficient production of T-tropic HIV-1 through upregulation at a certain stage of the viral life cycle, probably after the adsorption step

DNA barcoding reveals seasonal shifts in diet and consumption of deep-sea fishes in wedge-tailed shearwaters

<div><p>The foraging ecology of pelagic seabirds is difficult to characterize because of their large foraging areas. In the face of this difficulty, DNA metabarcoding may be a useful approach to analyze diet compositions and foraging behaviors. Using this approach, we investigated the diet composition and its seasonal variation of a common seabird species on the Ogasawara Islands, Japan: the wedge-tailed shearwater <i>Ardenna pacifica</i>. We collected fecal samples during the prebreeding (<i>N</i> = 73) and rearing (<i>N</i> = 96) periods. The diet composition of wedge-tailed shearwater was analyzed by Ion Torrent sequencing using two universal polymerase chain reaction primers for the 12S and 16S mitochondrial DNA regions that targeted vertebrates and mollusks, respectively. The results of a BLAST search of obtained sequences detected 31 and 1 vertebrate and mollusk taxa, respectively. The results of the diet composition analysis showed that wedge-tailed shearwaters frequently consumed deep-sea fishes throughout the sampling season, indicating the importance of these fishes as a stable food resource. However, there was a marked seasonal shift in diet, which may reflect seasonal changes in food resource availability and wedge-tailed shearwater foraging behavior. The collected data regarding the shearwater diet may be useful for <i>in situ</i> conservation efforts. Future research that combines DNA metabarcoding with other tools, such as data logging, may provide further insight into the foraging ecology of pelagic seabirds.</p></div

Comparison of fish prey composition between breeding phases.

<p>RRA: number of sequence reads of a particular food taxon divided by the number of total sequence reads of the samples used in statistical analysis, FOO: number of samples that included a particular food taxon divided by the total number of samples used in the statistical analysis. (a) Prebreeding period (RRA), (b) prebreeding period (FOO), (c) rearing period (RRA), and (d) rearing period (FOO).</p

Diet dissimilarity between prebreeding and rearing.

<p>(A) Individual diet samples displayed as a dendrogram obtained from a cluster analysis of prey item sequences. The blue and orange tips in the dendrogram indicate fecal samples collected during the prebreeding and rearing periods, respectively. The column graphs below the dendrogram indicate the fish and mollusk compositions of the sample. The color of each taxon is as shown in Figs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0195385#pone.0195385.g001" target="_blank">1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0195385#pone.0195385.g002" target="_blank">2</a>. (B) Box plot comparison of the number of fish operational taxonomic units (OTUs) per fecal sample between breeding phases. We identified samples to the genus level even if some sequences matched at the species level because the current sequence database does not cover all prey species distributed in the wedge-tailed shearwater foraging range. The left plot depicts the samples collected during the prebreeding period, and the right plot depicts the samples collected during the rearing period. The bold lines in the box indicate the median, and the edges of the box indicate the quartiles. A circle in the prebreeding plot indicates an outlier.</p

List of vertebrate taxa identified based on 12S sequences and the corresponding number of reads.

<p>List of vertebrate taxa identified based on 12S sequences and the corresponding number of reads.</p

Comparison of mollusk prey composition between breeding phases.

<p>(a) Prebreeding period (RRA), (b) prebreeding period (FOO), (c) rearing period (RRA), and (d) rearing period (FOO).</p

Differences in diet among fecal samples determined using nonmetric multidimensional scaling (NMDS).

<p>NMDS was based on the Bray–Curtis dissimilarity in the read rates of individual samples. Samples were classified by breeding stage. The black circles indicate prebreeding samples and the red triangles indicate rearing samples.</p