SUMMARYIt has recently been shown that several members of the tetraspan superfamily, including CD9 and CD63, associate with each other and with  1 integrins. In this study, we examined the distribution of a recently identified tetraspan, PETA-3 (CD151), and of CD9, CD63, ␣ 5  1, and the integrin  1 chain in normal human tissues by the indirect immunoperoxidase and alkaline phosphatase-anti-alkaline phosphatase techniques. PETA-3 showed a broad distribution and was expressed by endothelium, epithelium, Schwann cells, and dendritic cells and by skeletal, smooth, and cardiac muscle. Expression in skin was mostly restricted to the basal cells of the epidermis and was downregulated on differentiation. In the small intestine, PETA-3 was expressed by crypt and villous enterocytes with a mostly basolateral distribution, but was not detectable on the brush border. CD9 was expressed on the plasma membrane of enterocytes in crypts and at the bases of the villi whereas CD63 demonstrated a unique granular appearance concentrated in the apical cytoplasm below the brush border. The findings of this study show co-localization of PETA-3 with CD9, CD63, ␣ 5  1, and  1 in particular tissues, demonstrating that tetraspan/integrin complexes may occur. However, the lack of co-localization of these antigens in other tissues also implies distinct roles for these molecules. ( J Histochem Cytochem 45:515-525, 1997 )
The long-standing controversy regarding whether Giardia intestinalis is a single species prevalent in both human and animal hosts or a species complex consisting of morphologically similar organisms that differ in host range and other biotypic characteristics is an issue with important medical, veterinary, and environmental management implications. In the past decade, highly distinct genotypes (some apparently confined to particular host groups) have been identified by genetic analysis of samples isolated from different host species. The aim of this study was to undertake a phylogenetic analysis of G. intestinalis that were representative of all known major genetic groups and compare them with other Giardia species, viz. G. ardeae, G. muris, and G. microti. Segments from four "housekeeping" genes (specifying glutamate dehydrogenase, triose phosphate isomerase, elongation factor 1 alpha, and 18S ribosomal RNA) were examined by analysis of 0.48-0.69-kb nucleotide sequences determined from DNA amplified in polymerase chain reactions from each locus. In addition, isolates were compared by allozymic analysis of electrophoretic data obtained for 21 enzymes representing 23 gene loci. The results obtained from these independent techniques and different loci were essentially congruous. Analyses using G. ardeae and/or G. muris as outgroups supported the monophyly of G. intestinalis and also showed that this species includes genotypes that represent at least seven deeply rooted lineages, herein designated assemblages A-G. Inclusion of G. microti in the analysis of 18S rRNA sequence data demonstrated the monophyly of Giardia with the same median body morphology but did not support the monophyly of G. intestinalis, instead placing G. microti within G. intestinalis. The findings support the hypothesis that G. intestinalis is a species complex and suggest that G. microti is a member of this complex.
Ag-presenting molecule CD1 and CD1-restricted NKT cells are known to contribute to defense against a range of infectious pathogens, including some viruses. CD1-restricted NKT cells, a distinct subpopulation of T cells, have striking and rapid effector functions that contribute to host defense, including rapid production of IFN-γ and IL-4, and activation of NK cells. Consideration of the important contributions of innate and adaptive immunity to clearance of HSV prompted us to investigate the role of CD1 and of NKT cells expressing the Vα14-Jα281 TCR in the pathogenesis of HSV infection. To address this issue, we compared infection in wild-type mice with that in CD1 gene knockout (GKO) and Jα281 GKO mice. In this study, we report impaired clearance of virus and viral Ags, and more florid acute infection in mice lacking CD1 (and by inference, CD1-restricted T cells), in comparison with parental C57BL6 mice. In Jα281 GKO mice there was also impairment of virus clearance, resembling that seen in CD1 GKO mice. These results imply roles for the Vα14-Jα281 subset of NKT cells and for CD1d in control of HSV infection.
The ovulatory process has been compared with inflammation because several classical inflammatory mediators appear to participate in this process. One component of the inflammatory reaction is the migration of leukocytes to the site of inflammation and the subsequent activation of these cells. We have reported recently that perfusion of leukocytes into the rat ovary in vitro enhances the number of LH-induced ovulations, which suggests an active role of leukocytes in ovulation. In the present study we characterize immunohistochemically the distribution of macrophages, T lymphocytes, and granulocytes in the ovaries of untreated immature rats and of eCG-hCG-primed rats killed prior to hCG injection, at ovulation, and at 33-36 h post-ovulation. Macrophages, identified with monoclonal antibodies ED1 and ED2, were the major leukocyte population and were found primarily in the medullary region surrounding the blood vessels. The density of the cells in this region increased continuously during development to sexual maturity and until after ovulation. Macrophages were also present in the thecal layer of the preovulatory follicles, and the numbers of these cells increased about 5-fold in this area in ovulating follicles (12 h after hCG) compared to preovulatory follicles (before hCG). A portion of macrophages in both areas expressed major histocompatibility complex (MHC) class II antigens (OX6+); these cells were present mostly in the medullary region, with no apparent change in density during the periovulatory period. Neutrophilic granulocytes comprised a lesser proportion of the total leukocyte population in the medullary region but were abundant in the thecal layer. The density of neutrophils increased 3-fold in the medullary region and 8-fold in the thecal region in ovulatory compared to preovulatory follicles. T lymphocytes (OX52+) were evenly distributed at relatively low density in the medulla and the stroma of the cortex. Most T lymphocytes expressed the CD8 antigen (OX8+) and hence were of the MHC class I-restricted phenotype. Few T lymphocytes were present in the thecal layer. In summary, macrophages, neutrophilic granulocytes, and T lymphocytes are present in the ovary at ovulation. There is a selective increase in the numbers of macrophages and neutrophilic granulocytes in the medullary region and in the thecal layer as the ovulatory period progresses, indicating that these cells may actively be involved in the tissue remodeling occurring at ovulation.
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