SummaryTo determine whether T cells, like B cells, can become clonally expanded in normal individuals as a function of age, we compared the T cell VB repertoire of cord blood to that of peripheral blood from normal donors over 65 yr of age. T cells from elderly subjects contained expanded subsets (greater than the mean + three standard deviations) ofT cell receptor (TCR) VB populations. These expanded subsets were observed primarily among CDS, but not CD4 cells, represented up to 37.5% of all CD8 cells, and were present in most elderly subjects. An expanded V~5.2/3 CD8 subset and a VB6.7a CD8 subset from separate donors were analyzed by reverse transcriptase-polymerase chain reaction, cloning and sequencing of the TCR ~ chain VDJ junction. In both cases the expanded subsets were mono-or oligoclonal while control CD4 populations were polyclonal. Using two-color flow cytometry it was possible to identify the expanded Vf36.7a subset as CD8 + CD28-CDllb + cells. In three of five random old subjects similar expansions of V~ subsets were found specifically in the CD8 + CD28-subpopulation, an interesting subset of cytotoxic T lymphocytes, known to lack proliferative responses to TCR stimuli. It is common practice to use the demonstration of donality as a diagnostic indicator for T cell lymphoma/leukemia. In view of the high frequency of expanded T clones of T cells in normal elderly subjects the diagnostic usefulness of this test should be reexamined.

The immortalized corneal (HCLE) and conjunctival (HCjE) cell lines exhibit the mucin gene expression repertoire of their native epithelia. These cell lines will be useful in determining regulation of ocular surface mucin gene expression and, potentially, goblet cell differentiation.

No abstract

Drosophila is the genus responsible for the birth of experimental genetics, but the taxonomy of drosophilids is difficult because of the overwhelming diversity of the group. In this study, we assembled sequences for 358 species (14 genera, eight subgenera, 57 species groups, and 65 subgroups) to generate a maximum-likelihood topology and a Bayesian timescale. In addition to sampling an unprecedented diversity of Drosophila lineages, our analyses incorporated a geographical perspective because of the high levels of endemism. In our topology, Drosophila funebris (Fabricius, 1787) (the type species of Drosophila) is tightly clustered with the pinicola subgroup in a North American clade within subgenus Drosophila. The type species of other drosophilid genera fall within the Drosophila radiation, presenting interesting prospects for the phylogenetic taxonomy of the group. Our timescale suggests that a few drosophilid lineages survived the Cretaceous-Palaeogene (K-Pg) extinction. The drosophilid diversification began during the Palaeocene in Eurasia, but peaked during the Miocene, an epoch of drastic climatic changes. The most recent common ancestor of the clades corresponding to subgenera Sophophora and Drosophila lived approximately 56 Mya. Additionally, Hawaiian drosophilids diverged from an East Asian lineage approximately 26 Mya, which is similar to the age of the oldest emerging atoll in the Hawaiian-Emperor Chain. Interestingly, the time estimates for major geographical splits (New World versus Asia and Africa versus Asia) were highly similar for independent lineages. These results suggest that vicariance played a significant role in the radiation of fruit flies.

BackgroundThe Triatomini and Rhodniini (Hemiptera: Reduviidae) tribes include the most diverse Chagas disease vectors; however, the phylogenetic relationships within the tribes remain obscure. This study provides the most comprehensive phylogeny of Triatomini reported to date.MethodsThe relationships between all of the Triatomini genera and representatives of the three Rhodniini species groups were examined in a novel molecular phylogenetic analysis based on the following six molecular markers: the mitochondrial 16S; Cytochrome Oxidase I and II (COI and COII) and Cytochrome B (Cyt B); and the nuclear 18S and 28S.ResultsOur results show that the Rhodnius prolixus and R. pictipes groups are more closely related to each other than to the R. pallescens group. For Triatomini, we demonstrate that the large complexes within the paraphyletic Triatoma genus are closely associated with their geographical distribution. Additionally, we observe that the divergence within the spinolai and flavida complex clades are higher than in the other Triatoma complexes.ConclusionsWe propose that the spinolai and flavida complexes should be ranked under the genera Mepraia and Nesotriatoma. Finally, we conclude that a thorough morphological investigation of the paraphyletic genera Triatoma and Panstrongylus is required to accurately assign queries to natural genera.