An R5-tropic SHIV was previously generated using a primary HIV-1 subtype-C envelope. We have further characterized this SHIV in two species of macaques. To determine whether this isolate is transmissible vaginally, female pigtailed macaques were inoculated with 2x10 TCID of SHIV by the vaginal route. Animals became infected with a high peak plasma viremia (>107 viral copies/mL) and rapid seroconversion. The viremia was accompanied by CD4 lymphocytopenia in the gut lamina propria lymphocyte (LPL) population. Comparable CD4 T-cell loss was not seen in peripheral blood and colonic lymph nodes. These findings demonstrate a unique R5-tropic SHIV that can be used to study envelope-related issues in vaginal transmission of the most prevalent subtype of HIV-1. We also found that rhesus macaques intravenously inoculated with I x 10 TCID of SHIV became infected and showed CD4 lymphocytopenia in the gut LPL population. Despite inactivation of the vpu gene in SHIV, the virus appears to target mainly gut-associated lymphoid tissues during the initial stage of infection as has been described for SHIV, another R5-tropic (subtype B) recombinant virus. Our data indicate that the R5-mediated CD4 lymphocytopenia in the gut is likely independent of HIV-1 genotypes and of the function of vpu at the acute phase of viral infection.

Zhiwei Chen    Zhao Xiuqing    Huang Yaoxing    Gettie Agegnehu    Ba Lei    Blanchard James    何大一    

Journal of Acquired Immune Deficiency Syndromes

2002

Human immunodeficiency virus type 1 is characterized by extensive genetic heterogeneity. Having previously demonstrated that, in the peripheral blood, the initial viral population is more homogeneous than at subsequent stages of infection, we have extended our studies to tissue samples, allowing comparisons between viral populations in peripheral blood and tissues during both the acute and chronic stages of infection. We found that homogeneity in gp120 sequences during the acute infection phase is not just restricted to the peripheral blood but also extends to other tissue compartments. However, in chronically infected individuals, heterogeneous and distinct viral populations were found in different compartments. We therefore conclude that the dominant and homogeneous viral population observed during the acute infection phase is likely to infiltrate lymphoid tissues and form the genetic bases for subsequent diversification. It is therefore likely that the compartmentalization of viral sequences observed in chronically infected patients reflects a gradual diversification of a common dominant viral variant rather than the preferential migration of distinct viral populations to different tissue compartments at the beginning of infection.

Zhang Linqi    Rowe Leslie    He T.    Chung Christopher W.    Yu Jian    Wenjie Yu    Talal    Markowitz Martin    何大一    

Journal of Virology

2002

Sixteen subjects were treated with highly active antiretroviral therapy within 120 days of the onset of symptoms of newly acquired human immunodeficiency virus type 1 (HIV-1) infection. Eleven of the 16 participated in an adjunctive therapeutic vaccine trial. After a mean of 3.2 years of treatment, they elected to discontinue therapy. Virus rebound occurred in all subjects and was followed by a spontaneous, transient although significant reduction in log plasma HIV-1 RNA level, ranging from 0.3 to 3.1 logcopies/mL. Despite evidence of the induction of HIV-1-specific cell-mediated immune responses, plasma viremia was not persistently suppressed to <500 copies/mL in any subject. The magnitude and dynamics of virus rebound were similar in both vaccinated and unvaccinated subjects. Nevertheless, given the transient suppression of viremia observed in nearly all subjects after treatment has been discontinued, further investigations of adjunctive vaccination with optimized antiretroviral therapy in treating HIV-1 infection are warranted.

Markowitz Martin    金侠    Arlene Hurley    Simon Viviana    Bharat Ramratnam    Louie Michael    Deschenes Geoffrey R.    Ramanathan Murugappan    Barsoum Shady    Vanderhoeven Jeroen    He T.    Chung Christopher W.    John Murray    Alan Perelson    Zhang Linqi    何大一    

Journal of Infectious Diseases

2002

It has been known since 1986 that CD8 T lymphocytes from certain HIV-1-infected individuals who are immunologically stable secrete a soluble factor, termed CAF, that suppresses HIV-1 replication. However, the identity of CAF remained elusive despite an extensive search. By means of a protein-chip technology, we identified a cluster of proteins that were secreted when CD8 T cells from long-term nonprogressors with HIV-1 infection were stimulated. These proteins were identified as α-defensin 1, 2, and 3 on the basis of specific antibody recognition and amino acid sequencing. CAF activity was eliminated or neutralized by an antibody specific for human α-defensins. Synthetic and purified preparations of α-defensins also inhibited the replication of HIV-1 isolates in vitro. Taken together, our results indicate that α-defensin 1, 2, and 3 collectively account for much of the anti-HIV-1 activity of CAF that is not attributable to β-chemokines.

Zhang Linqi    Wenjie Yu    He T.    Yu Jian    Caffrey Rebecca E.    Dalmasso Enrique A.    Fu Siyu    Pham Thang    Mei Jianfeng    Ho Jaclyn J.    Zhang Wenyong    Lopez    何大一    

Science

2002

Human immunodeficiency virus type 1 (HIV-1)-infected individuals with HLA-B*35 allelic variants B*3502/3503/3504/5301 (B*35-Px) progress more rapidly to AIDS than do those with B*3501 (B*35-PY). The mechanisms responsible for this phenomenon are not clear. To examine whether cellular immune responses may differ according to HLA-B*35 genotype, we quantified HIV-1-specific CD8-T-cell (CTL) responses using an intracellular cytokine-staining assay with specimens from 32 HIV-1-positive individuals who have B*35 alleles. Among them, 75% had CTL responses to Pol, 69% had CTL responses to Gag, 50% had CTL responses to Nef, and 41% had CTL responses to Env. The overall magnitude of CTL responses did not differ between patients bearing B*35-Px genotypes and those bearing B*35-PY genotypes. A higher percentage of Gag-specific CTL was associated with lower HIV-1 RNA levels (P = 0.009) in individuals with B*35-PY. A negative association between CTL activity for each of the four HIV antigens and viral load was observed among individuals with B*35-PY, and the association reached significance for Gag. No significant relationship between CTL activity and viral load was observed in the B*35-Px group. The relationship between total CTL activity and HIV RNA among B*35-Px carriers differed significantly from that among B*35-PY carriers (P < 0.05). The data are consistent with the hypothesis that higher levels of virus-specific CTL contribute to protection against HIV disease progression in infected individuals with B*35-PY, but not in those with B*35-Px.

金侠    Gao Xiaojiang    Ramanathan Murugappan    Deschenes Geoffrey R.    Nelson George    Stephen O'Brien    Goedert James J.    何大一     O'Brien Thomas R.    Mary Carrington   

Journal of Virology

2002

Successful allogeneic hematopoietic stem cell transplantation (HSCT) requires reconstitution of normal T-cell immunity. Recipient thymic activity, biologic features of the allograft, and preparative regimens all contribute to immune reconstitution. We evaluated circulating T-cell phenotypes and T-cell receptor rearrangement excision circles (TRECs) in 331 blood samples from 158 patients who had undergone allogeneic HSCTs. All patients had received myeloablative conditioning regimens and were full donor chimeras in remission. Younger patients exhibited more rapid recovery and higher TRECs (P = .02). Recipients of T-cell-depleted allografts initially had lower TRECs than unmodified allograft recipients (P < .01), but the difference abated beyond 9 months. TREC level disparities did not achieve significance among adults with respect to type of allograft. Measurable, albeit low, TREC values correlated strongly with severe opportunistic infections (P < .01). This finding was most notable during the first 6 months after transplantation, when patients are at greatest risk but before cytofluorography can detect circulating CD45RA T cells. Low TRECs also correlated strongly with extensive chronic graft-versus-host disease (P < .01). Recipients of all ages of either unmodified or T-cell-depleted allografts therefore actively generate new T cells. This generation is most notable among adult recipients of T-cell-depleted allografts, most of whom had also received antithymocyte globulin for rejection prophylaxis. Low TREC values are significantly associated with morbidity and mortality after transplantation. T-cell neogenesis, appropriate to age but delayed in adult recipients of T-cell-depleted allografts, justifies interventions to hasten this process and to stimulate desirable cellular immune responses. © 2002 by The American Society of Hematology.

Sharon Lewin    Glenn Heller    Zhang Linqi    Rodrigues Elaine G.    Skulsky Eva    Marcel rm Van Den Brink    Small Trudy N.    Nancy Kernan    O'Reilly Richard J.    何大一     James Young   

Blood

2002

There is an urgent need to come up with a vaccine that will curtail the spread of HIV-1. To be successful, the scientific community must work in concert to develop sound strategies based on a deeper understanding of the virus. Significant technological advances are also required to overcome the unique obstacles posed by HIV-1. Some of the challenges we face in this endeavor are discussed here.

何大一     Huang Yaoxing   

Cell

2002

Deuterated glucose labeling was used to measure the in vivo turnover of T lymphocytes. A realistic T cell kinetic model, with populations of resting and activated T cells, was fitted to D-glucose labeling data from healthy and HIV-1-infected individuals before and after antiretroviral treatment. Our analysis highlights why HIV-1 infection, which increases the fraction of both CD4 and CD8 T lymphocytes that are proliferating (Ki67), leads to CD4 but not CD8 depletion. We find that HIV-1 infection tends to increase the rates of death and proliferation of activated CD4 T cells, and to increase the rate at which resting CD4 T cells become activated, but does not increase the fraction of activated CD4 T cells, consistent with their preferential loss in HIV-1-infected individuals. In contrast, HIV-1 infection does not lead to an increase in proliferation or death rates of activated CD8 T cells, but did increase the fraction of activated CD8 T cells, consistent with these cells remaining in an activated state longer and undergoing more rounds of proliferation than CD4 T cells. Our results also explain why telomeres shorten in CD8 cells, but not in CD4 cells of HIV-1-infected patients, compared with age-matched controls.

Ruy Ribeiro    Mohri Hiroshi    何大一     Alan Perelson   

Proceedings of the National Academy of Sciences of the United States of America

2002

Members of HIV-1 group M are responsible for the vast majority of AIDS cases worldwide and have been classified on the basis of their phylogenetic relationships into nine roughly equidistant clades, termed subtypes. Although there are no known phenotypic correlates for these genotypes, the disproportionate spread of certain of these lineages has been taken to indicate that subtype-specific biological differences may exist. The subtype nomenclature thus remains an important molecular epidemiological tool with which to track the course of the group M pandemic. In this study, we have characterized HIV-1 strains described previously as unusual subtype A variants on the basis of partial sequence analysis. Six such strains from Cyprus (CY), South Korea (KR), and the Democratic Republic of Congo (CD) were PCR amplified from infected cell culture or patient PBMC DNA, cloned, and sequences in their entirety (94CY017, 97KR004, 97CDKTB48, and 97CDKP58) or as half genomes (97CDKS10 and 97CDKFE4). Distance and phylogenetic analyses showed that four of these viruses (94CY017, 97CDKTB48, 97CDKFE4, and 97CDKS10) were closely related to each other, but quite divergent from all other HIV-1 strains, except for subtype A viruses, which represented their closest relatives. In phylogenetic trees from gag, pol, env, and nef regions, the four newly characterized HIV-1 strains formed a distinct sister clade to subtype A, which was as closely related to subtype A as subsubtypes F1 and F2 are to each other. According to current nomenclature rules, this defines a subsubtype, which we have tentatively termed A2. The two other viruses, 97KR004 and 97CDKP58, as well as a full-length HIV-1 sequence from the sequence database (ZAM184), were found to represent complex A2/D, A2/G, and A2/C recombinants, respectively. These results indicate that HIV-1 subtype A is composed of two subsubtypes (A1 and A2), both of which appear to have a widespread geographic distribution. The A2 viruses described here represent the first reference reagents for this new group M lineage.

Gao Feng    Vidal Nicole    Li Yingying    Trask Stanley A.    Chen Yalu    Demetriades    何大一     Kim Jinwook    Myoung don Oh    Choe Kang-Won    Salminen Mika O.    Robertson David L.    Shaw George M.    Hahn Beatrice H.    Martine Peeters   

AIDS Research and Human Retroviruses

2001

We have characterized the functional integrity of seven primary Nef isolates: five from a long-term nonprogressing human immunodeficiency virus (HIV)-infected individual and one each from two patients with AIDS. One of the seven Nefs was defective for CD4 downregulation, two others were defective for PAK-2 activation, and one Nef was defective for PAK-2 activation and major histocompatibility complex (MHC) class I downregulation. Five of the Nefs were tested and found to be functional for the enhancement of virus particle infectivity. The structural basis for each of the functional defects has been analyzed by constructing a consensus nef, followed by mutational analysis of the variant amino acid residues. Mutations A29V and F193I were deleterious to CD4 downregulation and PAK-2 activation, respectively, while S189R rendered Nef defective for both MHC class I downregulation and PAK-2 activation. A search of the literature identified HIVs from five patients with Nefs predominantly mutated at F193 and from one patient with Nefs predominantly mutated at A29. A29 is highly conserved in all HIV subtypes except for subtype E. F193 is conserved in subtype B (and possibly in the closely related subtype D), but none of the other HIV group M subtypes. Our results suggest that functional distinctions may exist between HIV subtypes.

Foster John    Molina R. P.    Luo T.    Vivek Arora    Huang Yaoxing    何大一     Jersey víctor García   

Journal of Virology

2001