Lamina propria lymphocytes, not macrophages, express CCR5 and CXCR4 and are the likely target cell for human immunodeficiency virus type 1 in the intestinal mucosa

Most human immunodeficiency virus type 1 (HIV-1) infections are acquired via mucosal surfaces, and transmitted viruses are nearly always macrophage-tropic, suggesting that mucosal macrophages participate in early HIV-1 infection. Mucosal lymphocytes isolated from normal human intestine expressed CD4 (14,530+/-7970 antibody-binding sites [ABSs]/cell), CCR5 (2730+/-1524 ABSs/cell), and CXCR4 (2507+/-1840 ABSs/cell), but intestinal macrophages, which also expressed CD4 (2959+/-2695 ABSs/cell), displayed no detectable CCR5 or CXCR4 ABS. The absence of CCR5 on intestinal macrophages was not due to expression of the Delta32 deletion allele because matched-blood monocytes expressed CCR5. CCR5(+)CXCR4(+) intestinal lymphocytes supported both R5 (BaL) and X4 (IIIB) HIV-1 replication, whereas the CCR5(-)CXCR4(-) macrophages were not permissive to either isolate or other laboratory isolates (ADA and DJV) and primary isolates (MDR 24 and JOEL). In the intestinal mucosa, lymphocytes, not macrophages, are the likely target cell for R5 (and X4) HIV-1 and are the major source of HIV-1 production during early infection.

Biological parameters of HIV-1 infection in primary intestinal lymphocytes and macrophages

Mucosal surfaces are the portal of entry for most HIV-1 infections and play an important role in disease pathogenesis. To characterize the biological parameters of HIV-1 infection in mucosal cells, we used purified lamina propria lymphocytes and macrophages from normal human small intestine to determine the distribution of the HIV-1 receptor and coreceptors on intestinal mononuclear cells and the permissiveness of these cells to HIV-1 infection. Lamina propria lymphocytes expressed CD4, CCR5, and CXCR4. In contrast, lamina propria macrophages expressed CD4 but not CCR5 or CXCR4. Intestinal lymphocytes supported replication by R5 and X4 isolates of HIV-1, but lamina propria macrophages were permissive to neither. RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha), and MIP-1beta inhibited infection of intestinal lymphocytes by BaL, indicating that R5 infection of the intestinal lymphocytes was mediated by CCR5. Thus, resident lamina propria lymphocytes, not macrophages, are the target mononuclear cell for HIV-1 infection in the intestinal mucosa during early HIV-1 infection.

An association study of polymorphisms in the alpha-antichymotrypsin gene for Alzheimer disease in Han-Chinese

Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and DNA sequencing were employed to screen the coding region of the alpha-antichymotrypsin (AACT) gene in Han-Chinese population for polymorphism possibly associated with Alzheimer's disease (AD). Consequently, seven polymorphic sites including 25A>G, 39G>A, 370C>T, 662T>G, 892C>T, 923T>C and 1332A>G were detected. Of them, the 25A>G was reported previously and the others are all novel. We subsequently focused on the 25A>G and the 39G>A polymorphism that were of interest to us and conducted an association study of them by another scanning of 246 controls that matched the AD patients. Statistic test showed that both genotype (p=0.0378, Fisher's exact, two tailed) and allele frequency (p=0.0382, Fisher's exact, two tailed) of 39G>A are different between AD patients and the controls. As for 25A>G, lain only the heterozygous genotype A/G associates with AD (p=0.0220, chi(2)), but not the A allele frequency (p=0.1141, chi(2)).

[The electroluminescence of organic and polymer thin film materials]

In recent years, researches on electroluminescence (EL) of organic and polymer thin film materials have been made with an outstanding progress, and have attracted much interest because of its large-area, full color, high luminance displays which can be driven with low dc voltage. In this paper, the history of the development on electroluminescence, the devices and the selection of luminescent materials and the electroluminescence principle are introduced briefly.

Selecting and expressing protective single-chain Fv fragment to stabilize L-asparaginase against inactivation by trypsin

Four non-inhibitory specific single-chain Fv (sc Fv) fragments directed against L-asparaginase (ASNase) of Escherichia coli were selected from a synthetic phage-display scFv library. The scFv46 fragment could enhance the resistance of ASNase to trypsin proteolysis, with 70% of the initial ASNase activity present after the ASNase-scFv46 complex had been treated with trypsin for 30 min at 37 degrees C, whereas little residual activity was detected without the scFv46 fragment. The scFv46 gene was cloned to an expression vector pET-21a and expressed at high levels (about 45% of total cell protein) in E. coli BL21 (DE3) as inclusion bodies. The refolded and purified scFv46 fragment was proved to protect ASNase, and the protective effect was further confirmed by SDS/PAGE. It was found that under optimum conditions of molar ratio of scFv to ASNase, incubation time and temperature, the residual activity of the ASNase-scFv46 complex could reach about 78% after treatment with trypsin for 30 min at 37 degrees C. The results demonstrated that scFv fragments prepared by phage-antibody library technology could be used to protect target proteins.

Structural analysis of the gene encoding RP58, a sequence-specific transrepressor associated with heterochromatin

RP58, a sequence-specific transcriptional repressor sharing homology with the POZ domain of a number of zinc-finger proteins, is highly synthesized in brain and localized in condensed chromatin regions, suggesting a role in transcriptional repression in the central nervous system. In the present study, genomic clones of the human rp58 gene were isolated to determine the complete genomic organization. Sequence analyses indicated that the human rp58 gene encoding the functional protein is uninterrupted over its entire 4.2 kb length. Comparison of the human and mouse rp58 genes revealed that they share not only a high homology in the amino acid sequences of their encoded proteins, but also a high degree of structural similarity at the genomic level. RT-PCR analysis also demonstrated the existence of an alternatively spliced form of rp58 similar to the previously reported zinc-finger cDNA, C2H2-171. Chromosomal mapping by fluorescence in situ hybridization analysis allowed localization of the rp58 gene to human chromosome 1q44 ter, a genetic region associated with a number of human malignancies and neurological disorders.

[Culture conditions of engineered strain of L-asparaginase and the recombinant plasmid stability]

The growth curves of engineered strain JM105(pASN) were different in LB and M-3 media. The expression level and activity of L-asparaginase were affected apparently by both biomass and induction time. Glucose repression of production of L-asparaginase was found. The stability of the recombinant plasmid pASN in different host strains and in LB and M-3 media was determined. After cultivation inLB broth and M-3 media at 30 degrees C for more than 50 generations without antibiotic selection, then induced at 42 degrees C for up to 5 h, the engineered strains were proved to be stable, except for DHA alpha (pASN).

[Artificial Neural Network and its application to analytical chemistry]

Artificial Neural Network system(ANNs) was presented involving its theoretical basis, algorithm and performance. Its application to nonlinear calibration, pattern recognition and other related fields in analytical chemistry has been reviewed. 95 references are cited.

[The 1. 54 microm laser and upconversion luminescence of YELPP noncrystalline induced by 969 nm LD laser]

In this paper, the absorption of Er3+, Yb3+ penta-phosphate noncrystalline (YELPP) was measured and the basic spectral parameters were calculated. Adopting the longitudinal-pump method with a domestic diode laser (LD), we achieved CW 1.5 microm chipped laser in China for the first time. The power of 1.5 microm laser was quite stable. The target of 1.5 microm laser reached the international level of early 1990s' in this field. In addition, the up-conversion luminescence was measured under the condition that 1.5 microm laser was either oscillating or not. The relationship between 1.5 microm chipped laser and up-conversion luminescence was analyzed initially.

Mucosal events in the pathogenesis of human immunodeficiency virus type 1 infection

The interaction between human immunodeficiency virus type 1 (HIV-1) and primary mucosal cells isolated from normal human small intestine was investigated. Purified primary intestinal epithelial cells could transport cell-free HIV-1 to mononuclear cells, although the epithelial cells did not support viral replication. An unexpected finding was that primary intestinal macrophages were markedly less permissive to HIV-1 than were blood monocytes. The reduced permissiveness appeared to be due to the near absence of surface CCR5 on resident intestinal macrophages. Surface CCR5 could be up-regulated on the monocytes but not the intestinal macrophages by HIV-1 and gp120. Impaired permissiveness of intestinal macrophages to HIV-1 may play an important role in the low prevalence of HIV-1 mRNA-expressing macrophages in the lamina propria during HIV-1 infection in vivo. Characterization of the biologic properties of HIV-1 transport and infection in primary mucosal cells will be key to elucidating the pivotal role of mucosal surfaces in HIV-1 disease.

Intestinal macrophages display reduced permissiveness to human immunodeficiency virus 1 and decreased surface CCR5

BACKGROUND & AIMS

Because the role of intestinal mononuclear cells in the pathogenesis of human immunodeficiency virus 1 (HIV-1) disease has not been elucidated, we determined the biological properties of HIV-1 infection in primary intestinal macrophages.

METHODS

Mucosal macrophages purified from normal human jejunum were infected with well-characterized macrophage-tropic isolates of HIV-1 (ADA, DJV, and Ba-L).

RESULTS

Productive HIV-1 infection of intestinal macrophages was demonstrated by the release of p24 antigen, the presence of proviral DNA, and zidovudine inhibition of infection. Surprisingly, the titer of virus needed to establish infection of intestinal macrophages was 100-1000-fold higher than that required to infect peripheral blood derived macrophages. This marked reduction in the permissiveness of intestinal macrophages to HIV-1 was not caused by the isolation procedure or differences in CD4 expression. Instead, intestinal macrophages expressed almost no CCR5, the principal coreceptor for macrophage-tropic HIV-1, compared with blood-derived macrophages, although both cell types contained comparable levels of CCR5 messenger RNA. Exposure of blood-derived but not intestinal macrophages to HIV-1 or gp120 led to increased surface expression of CCR5.

CONCLUSIONS

Intestinal macrophages express reduced levels of HIV-1, probably because of impaired permissiveness to HIV-1 entry associated with the near absence of cell surface CCR5.

[Study on the human serums by absorption spectra]

The absorption spectra of normal human and cancer patient serums were measured, and those of human serum after adding some cancer cells were also measured. The results showed some difference in absorbance among the three kinds of serums. Some useful results were obtained.

Gastrointestinal infections in the immunocompromised host

Gastrointestinal infections are a frequent and important complication of immunodeficiency diseases and immunosuppressive therapy. Such infections may be severe, prolonged, or even fatal, whereas the same infections are typically mild and transient in immunocompetent persons. In this regard, the strong association between HIV-induced immunosuppression and the increased prevalence of severe enteric infections is strong evidence of the link between immune function and defense against enteric pathogens. Because gastrointestinal infections in immunocompromised persons are frequently severe and life-threatening, a vigorous approach to the diagnostic evaluation and therapeutic management is advocated by many clinical investigators. In this review, we summarize the important new developments, particularly during the past year, regarding gastrointestinal infections in immunocompromised persons.

Crystal structure of the complex between VEGF and a receptor-blocking peptide

Vascular endothelial growth factor (VEGF) is a specific and potent angiogenic factor and, therefore, a prime therapeutic target for the development of antagonists for the treatment of cancer. As a first step toward this goal, phage display was used to generate peptides that bind to the receptor-binding domain (residues 8-109) of VEGF and compete with receptor [Fairbrother, W. J., Christinger, H. W., Cochran, A. G., Fuh, G., Keenan, C. J., Quan, C., Shriver, S. K., Tom, J. Y. K., Wells, J. A., and Cunningham, B. C. (1999) Biochemistry 38, 17754-17764]. The crystal structure of VEGF in complex with one of these peptides was solved and refined to a resolution of 1.9 A. The 20-mer peptide is unstructured in solution and adopts a largely extended conformation when bound to VEGF. Residues 3-8 form a beta-strand which pairs with strand beta6 of VEGF via six hydrogen bonds. The C-terminal four residues of the peptide point away from the growth factor, consistent with NMR data indicating that these residues are flexible in the complex in solution. In contrast, shortening the N-terminus of the peptide leads to decreased binding affinities. Truncation studies show that the peptide can be reduced to 14 residues with only moderate effect on binding affinity. However, because of the extended conformation and the scarcity of specific side-chain interactions with VEGF, the peptide is not a promising lead for small-molecule development. The interface between the peptide and VEGF contains a subset of the residues recognized by a neutralizing Fab fragment and overlaps partially with the binding site for the Flt-1 receptor. The location of the peptide-binding site and the hydrophilic character of the interactions with VEGF resemble more the binding mode of the Fab fragment than that of the receptor.

Blunted thrombopoietin response to interferon alfa-induced thrombocytopenia during treatment for hepatitis C

Thrombocytopenia is common in advanced-stage liver disease and is partly caused by inadequate thrombopoietin (TPO) production in the failing liver. Treatment of chronic hepatitis C with interferon alfa (IFN-) often induces thrombocytopenia, sometimes even leading to discontinuation of treatment. TPO regulation in response to IFN--induced thrombocytopenia was studied in patients with chronic hepatitis C with and without cirrhosis (Child A). An in vitro culture system with HepG2 cells was used to demonstrate any direct effects of IFN- on TPO mRNA expression, TPO synthesis, or TPO secretion from liver cells. Thrombocyte count was lower (U test: P < .05) in patients with hepatitis C cirrhosis compared with patients with chronic hepatitis C without cirrhosis before IFN therapy, and decreased in both patient groups (Wilcoxon matched-pairs test: P < . 05) on IFN therapy, the median decrease in both groups being comparable (noncirrhotic patients, 35%; cirrhotic patients, 32%; U test: P = .57). TPO levels rose in noncirrhotic patients (Wilcoxon matched-pairs test: P < .05), but not in patients with cirrhosis (noncirrhotic patients' median increase: 43% vs. cirrhotic patients' median decrease: 5%; U test: P < .001). Even in patients without cirrhosis, the increase in TPO levels was relatively small for the decrease in platelet count. No effect of IFN- could be demonstrated on TPO mRNA expression in vitro, but TPO secretion from liver cells was significantly reduced. Lower platelet counts but similar TPO levels in patients with chronic hepatitis C and cirrhosis compared with noncirrhotic patients and a moderate increase in TPO levels in noncirrhotic patients with a missing increase in cirrhotic patients during IFN--induced thrombocytopenia provide further evidence for an impairment of TPO production in patients with cirrhosis and during IFN therapy. Recombinant human TPO could be of value in patients developing severe thrombocytopenia under IFN- therapy.

RP58 associates with condensed chromatin and mediates a sequence-specific transcriptional repression

An approximately 120-amino acid domain present generally at the NH2 termini, termed the POZ domain, is highly conserved in various proteins with zinc finger DNA binding motifs. We have isolated a novel protein sharing homology with the POZ domain of a number of zinc finger proteins, including the human BCL-6 protein. By using a binding site selection technique (CAST), a high affinity binding site of the protein was determined to be (A/C)ACATCTG(G/T)(A/C), containing the E box core sequence motif. The protein was shown to repress transcription from a promoter linked to its target sequences and was hence named RP58 (Repressor Protein with a predicted molecular mass of 58 kDa). Immunogold electron microscopic study revealed that almost all RP58 is localized in condensed chromatin regions. These observations demonstrate for the first time that a protein mediating a sequence-specific transcriptional repression associates with highly condensed chromatin. We suggest that RP58 may be involved in a molecular link between sequence-specific transcriptional repression and the organization of chromosomes in the nucleus.

[Anatomy and operation of agger nasi ethmoidal cells and frontal recess]

To reduce postoperative recurrency of nasal polyps and sinusitis, the anatomy of lateral wall of nasal cavity was studied in body head. It was found that there was a considerable wide area between the anterior attachment of the middle turbinate and the roof of ethmoidal sinus, just where the agger nasi ethmoidal cells and frontal recess lying. And also the medial wall of agger nasi ethmoidal cell is just above the anterior attachment of middle turbinate. In our operations, the bony structure above the anterior attachment of middle turbinate was resected to open the medial wall of agger nasi ethmoidal cells and the frontal recess, the lesions in them was removed carefully to reobtain a well drainage. 15 cases were followed up for 0.5 to 1.5 years and the result was satisfying.

[Indirect sensitized upconversion in Tm3+ and Yb3+ codoped non-crystal pentaphosphate]

We report the blue upconversion luminescence of Tm3+ and Yb3+ codoped non-crystal pentaphosphate pumped by -798nm laser diode. The samples were directly excited to 3F4 level of Tm3+ ion. Two energy transfer processes between Tm3+ and Yb3+ contribute mainly to the population of 1G4 level of Tm3+. Phonon plays an important role in the upconversion process.

[Study on the effect of human herpesvirus 6 on replication of Epstein-Barr virus]

OBJECTIVE

To examine the effect of human herpesvirus 6(HHV-6) on the replication of Epstein-Barr virus (EBV) in cell lines.

METHODS

Both EBV-infected Raji cells and EBV-transformed lymphoblastoid cell lines (LCL) were infected with HHV-6. Immunofluoresence assay (IFA) with monoclonal antibodies (MAb) against HHV-6 was applied to confirm the infection of HHV-6 in the two cell lines. Expression of EBV antigen was examined by IFA using human anti-EBV serum.

RESULTS

Following HHV-6 infection, cytopathic effects (CPE) were observed in Raji cells but not in LCL. HHV-6 were detected in both cell lines by IFA with anti-HHV-6 MAb, but not in controls. EBV antigens were detected by IFA with human serum against EBV in both HHV-6 infected cell lines.

CONCLUSION

Data in this study suggest that HHV-6 promotes the expression of EBV antigen and may contribute to the pathogenesis of nasopharyngeal carcinoma in cooperation with EBV.

Acute exacerbation of autoimmune liver disease associated with hantaviral infection

Hantavirus is known to cause haemorrhagic fever with renal syndrome (HFRS). Although liver dysfunction has been reported in HFRS, hepatic manifestations of hantaviral infection have not been well described. We describe a case of autoimmune cholangitis in which an exacerbation of hepatitis was associated with hantaviral infection. Seroconversion of both IgG- and IgM-class antibodies to hantavirus was noted coincident with acute exacerbation of hepatitis, which was resolved promptly by treatment with corticosteroid. No extrahepatic manifestations were noted. This case suggests that hantavirus may trigger acute exacerbation of autoimmune liver disease without extrahepatic manifestations and that it may cause community-acquired hepatitis.

[Three-dimensional volumetric display--a new application of frequency up-conversion]

This paper discusses the present research situation and the application prospect of 3-D volumetric display technology. The possible usability and science significance of frequency up-conversion in 3-D volumetric display field are also demonstrated systematically. In ZBLAN: Pr, Yb glasses, we primarily demonstrated and achieved a new application of frequency up-conversion three dimensional volumetric display, using the two-frequency up-conversion of the rare earth ions. The efficiency of luminescence of Pr was enhanced much by the energy transfer between Pr and Yb ions.

The effect of anti-CD3-immunotoxin on T lymphocyte function in vitro

Recent advances in the design of immunotoxins (IT) have yielded significant improvements. FN18-CRM9, a construct of anti-CD3 epsilon mAb FN18 and mutated diphtheria toxin CRM9 has exhibited high specificity, low systemic toxicity and unusual efficacy compared to previous iterations of immunotoxins. Others and we have examined this anti-CD3-IT for the purpose of inducing immunological tolerance through selective ablation of T cells in rhesus macaques and have obtained encouraging results. In order to characterize its mode of action, we have examined its effects on peripheral blood and lymph node T cell killing in vitro. We have studied the cytotoxic mechanism induced by this anti-CD3-IT as well as its effects on proliferation, phenotypic changes and cytokine production (IL2, IFN gamma and TNF alpha). The results indicate that anti-CD3-IT was highly specific for T cell killing at doses as low as 1 x 10(6) micrograms/ml and showed a maximal effect at 48 h after exposure. The toxicity was restricted to T cells, as B cells and other bystander cells were spared. This immunotoxin was shown to induce T cell apoptosis, as assessed by TUNEL assay, DNA content and cytotoxicity. Fas expression was upregulated on T cells within 24 h after in vitro exposure to anti-CD3-IT, suggesting an early T cell activation phase prior to T cell death. T cell killing was manifest as an early cell cycle arrest at the G1/S phase transition, which appeared to virtually eliminate the production of cytokines. These findings corroborate the temporal, specificity and quantitative patterns for anti-CD3 immunotoxin administration previously observed in vivo.

Preclinical studies of allograft tolerance in rhesus monkeys: a novel anti-CD3-immunotoxin given peritransplant with donor bone marrow induces operational tolerance to kidney allografts

A major challenge in clinical transplantation today is to design a practical and effective protocol for tolerance induction compatible with cadaver organ transplantation. A preclinical rhesus monkey kidney allograft model using immediate peritransplant anti-CD3 immunotoxin (anti-CD3-IT) and donor bone marrow (DBM) is shown here to induce operational tolerance with prolonged graft survival in the absence of chronic immunosuppressive drugs. Bone marrow harvested from the kidney donor was depleted of mature alloantigen-presenting cells and T cells by removing DR(bright) cells and CD3(bright) cells, respectively. In outbred, major histocompatibility complex-incompatible donor-recipient pairs with high pretransplant mixed lymphocyte response and cytotoxic T lymphocyte precursor activity, four of six allografts survived for periods of 120 days to >1.5 years. Graft acceptance after peritransplant treatment followed robust elimination of both peripheral blood T cells and lymph node T cells. In most recipients given anti-CD3-IT and DBM infusion, anti-donor immunoglobulin G responses were completely inhibited. Microchimerism was observed in all recipients studied, including those not given DBM, but levels of microchimerism did not correlate with graft survival. Anti-CD3-IT induction in combination with modified DBM protocols such as the depletion of mature T cells and DR(bright) antigen-presenting cells may offer new opportunities to improve clinical tolerance protocols beyond those attempted in the clinic to date. Overall, these results with anti-CD3-IT show promise for development of cadaver transplant tolerance induction.

Infection of gastrointestinal tract macrophages by HIV-1

As the largest lymphoid organ and the largest reservoir of macrophages in the body, the gastrointestinal tract mucosa is probably the largest organ reservoir of macrophages infected with HIV-1. To elucidate the biology of HIV-1 infection of intestinal macrophages, we isolated lamina propria macrophages from normal human jejunum by neutral protease digestion, purified the cells by counterflow centrifugal elutriation, and then infected the cells with HIV-1. The lamina propria macrophages were permissive to macrophagetropic isolates of HIV-1 and substantially less permissive to lymphocyte-tropic isolates. Compared with blood monocytes, mucosal macrophages produced 2-3 logs less p24 antigen at peak infection. The reduced level of infection was not due to impaired macrophage viability, reduced CD4 expression, or the isolation procedure. These results confirm that macrophages isolated from the gastrointestinal tract mucosa can support HIV-1 production, albeit at a lower level than blood monocytes. The reduced level of virus production may reflect the unique biology of intestinal lamina propria macrophages.