Selective Transmission of R5 HIV-1 over X4 HIV-1 at the Dendritic Cell–T Cell Infectious Synapse Is Determined by the T Cell Activation State

Dendritic cells (DCs) are essential antigen-presenting cells for the induction of T cell immunity against HIV. On the other hand, due to the susceptibility of DCs to HIV infection, virus replication is strongly enhanced in DC–T cell interaction via an immunological synapse formed during the antigen presentation process. When HIV-1 is isolated from individuals newly infected with the mixture of R5 and X4 variants, R5 is predominant, irrespective of the route of infection. Because the early massive HIV-1 replication occurs in activated T cells and such T-cell activation is induced by antigen presentation, we postulated that the selective expansion of R5 may largely occur at the level of DC–T cell interaction. Thus, the immunological synapse serves as an infectious synapse through which the virus can be disseminated in vivo. We used fluorescent recombinant X4 and R5 HIV-1 consisting of a common HIV-1 genome structure with distinct envelopes, which allowed us to discriminate the HIV-1 transmitted from DCs infected with the two virus mixtures to antigen-specific CD4+ T cells by flow cytometry. We clearly show that the selective expansion of R5 over X4 HIV-1 did occur, which was determined at an early entry step by the activation status of the CD4+ T cells receiving virus from DCs, but not by virus entry efficiency or productivity in DCs. Our results imply a promising strategy for the efficient control of HIV infection

Development of an Equine Herpesvirus Type 4-Specific Enzyme-Linked Immunosorbent Assay Using a B-Cell Epitope as an Antigen

The equine herpesvirus type 4 (EHV-4)-specific region of glycoprotein G has served as an antigen for serodiagnosis and seroepizootic studies of EHV-4 infection (B. S. Crabb and M. J. Studdert, J. Virol. 67:6332-6338, 1993; S. Yasunaga, K. Maeda, T. Matsumura, K. Kai, H. Iwata, and T. Inoue, J. Vet. Med. Sci. 60:1133-137, 1998; S. Yasunaga, K. Maeda, T. Matsumura, T. Kondo, and K. Kai, J. Vet. Med. Sci. 62:687-691, 2000). Here we identified a major B-cell epitope in the type-specific region of EHV-4 and applied it as an antigen in enzyme-linked immunosorbent assays (ELISAs). A 24-amino-acid repeat sequence expressed as a glutathione S-transferase fusion protein specifically reacted as well as the type-specific region with sera from foals infected with EHV-4. Five synthetic peptides (12-mer peptides) in the repeat sequence were included as ELISA antigens. The results indicated that the 12-mer peptide MKNNPIYSEGSL contained a major B-cell epitope specific for EHV-4 infection. Inclusion of this 12-mer peptide in ELISAs for an epidemiological study specifically detected EHV-4 infection in the field. These results indicated that the 12-mer epitope was responsible for the type-specific antibody response and therefore is useful for seroepizootic studies and serodiagnosis of EHV-4 infection

Genetic diversity of Mycobacterium tuberculosis isolates from Tochigi prefecture, a local region of Japan

Abstract Background Foreign-born patients with tuberculosis (TB) may introduce globally disseminated isolates of Mycobacterium tuberculosis into large cities in Japan. The risk of dissemination of these isolates into local regions, however, has not been determined. This study analyzed the molecular epidemiology of M. tuberculosis isolates obtained from TB patients living in a local region of Japan. Methods Whole genome sequences of 169 M. tuberculosis isolates, obtained from 148 Japanese-born and 21 foreign-born patients living in Tochigi, Japan, were analyzed using the Comprehensive analysis server for the Mycobacterium t u b erculosis complex (CASTB). Results The 169 isolates were clustered into four clades; Lineage 2 (111 isolates 65.7%), Lineage 4 (43 isolates, 25.4%), Lineage 1 (13 isolates, 7.7%), and Lineage 3 (2 isolates, 1.2%). Of the 111 isolates belonging to Lineage 2, 79 (71.2%) were of the atypical Beijing sub-genotype. Of the 13 Lineage 1 isolates, nine (69.2%) were from foreign-born patients. The isolates belonging to Lineage 4 were further clustered into three clades, two containing isolates shared by both Japanese- and foreign-born patients. The two isolates belonging to Lineage 3 were obtained from foreign-born patients. Conclusions The genotypic diversity of M. tuberculosis in a local region of Japan is increased primarily by the presence of isolates obtained from foreign-born patients

Additional file 1: Figure S1. of Genetic diversity of Mycobacterium tuberculosis isolates from Tochigi prefecture, a local region of Japan

Geographical location of Tochigi Prefecture in Japan. Tochigi is one of the inland prefectures of the Northern portion of the Kanto region. Its population on March 1, 2007, was 2,014,931 persons. The area of Tochigi prefecture is approximately 6,400 km2, making it the 20th largest in Japan, but the largest in the Kanto region. (PPTX 127 kb

Additional file 2: Table S1. of Genetic diversity of Mycobacterium tuberculosis isolates from Tochigi prefecture, a local region of Japan

Geographic analysis of lineages of M. tuberculosis isolates obtained from foreign- and Japanese-born patients living in the North, Central, and South regions of Tochigi Prefecture. (DOCX 31 kb

Additional file 4: Figure S2. of Genetic diversity of Mycobacterium tuberculosis isolates from Tochigi prefecture, a local region of Japan

Associations between patient gender and Mycobacterium tuberculosis lineages. The stacked bar charts show the percentages of M. tuberculosis lineages by (A) countries of birth and (B) sampling period. The numbers of isolates are indicated on the graphs. (PPTX 133 kb

Additional file 3: Table S2. of Genetic diversity of Mycobacterium tuberculosis isolates from Tochigi prefecture, a local region of Japan

Associations between patient gender and lineages of M. tuberculosis isolates obtained from foreign- and Japanese-born patients. (DOCX 31 kb

Replication of recombinant HIV-1 encoding EGFP or DsRed.

<p>(A) Concentration of X4 HIV-1 (HIV_NL-432), X4 HIV-1 expressing EGFP (HIV_NL-E), X4 HIV-1 expressing DsRed (HIV_NL-D), or R5HIV-1 expressing DsRed (HIV_NLAD8-D) in PHA-stimulated PBMCs of two donors. Virus production was monitored by in-house p24 antigen ELISA. (B) FACS analysis of HIV-1-infected T cells expressing EGFP or DsRed at 7 dpi.</p

Genomic structure and co-receptor usage of recombinant HIV-1 encoding EGFP or DsRed.

<p>(A) The structure of provirus DNA encoding <i>EGFP</i> or <i>DsRed</i> designated as pNL-E and pNL-D for X4 HIV-1 and pNLAD8-D for R5 HIV-1. EGFP or DsRed is not expressed as a fusion protein of Env because of one base insertion after the Env stop codon. Nef is also independently expressed under the control of IRES. To confirm the coreceptor usage of these fluorescent HIV-1, 1G5 (B) cells, 1G5/CCR5 (C) cells were infected with HIV-1_NL432 (parent strain), HIV-1_NL-E, HIV-1_NL-D, or HIV-1_NLAD8-D. After 48 h post-infection, cell lysates were prepared and the Luc assay was performed. The data represents the averages ±SD of three independent experiments.</p