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Biomedical subjects

R B Lal

Publications and source records attributed to R B Lal.

At least 37 records · Page 2Linked to original sources
PubMed2000

Presence of human immunodeficiency virus (HIV) type 1, group M, non-B subtypes, Bronx, New York: a sentinel site for monitoring HIV genetic diversity in the United States.

In the United States, human immunodeficiency virus (HIV) type 1, group M, subtype B is the predominant subtype. A cross-sectional study of HIV-infected patients at the Bronx-Lebanon Hospital Center, Bronx, NY, between September 1997 and February 1998 identified 3 (1. 2%) of 252 persons infected with non-B subtypes: subtypes A and F, 1 each, and 1 potential recombinant subtype B(env)/F(prt). All 3 persons were born in the United States and tested positive for HIV antibodies between 1988 and 1997 while living in the Bronx. None reported travel to other countries, receipt of blood products, or drug injection. This study is among the first to indicate probable transmission of non-B HIV-1 subtypes in the United States. The occurrence of non-B HIV-1 subtypes in long-term US residents without a history of foreign travel may have implications for the evaluation and development of antiretroviral drugs, vaccines, and tests intended for use in the United States to diagnose HIV infection and screen blood.

Adolescent↗
PubMed2000

Human immunodeficiency virus (HIV) subtype surveillance of African-born persons at risk for group O and group N HIV infections in the United States.

A population-based surveillance registry was used to identify human immunodeficiency virus (HIV)-infected persons in the United States at increased risk for group O and group N infections (those born in or near African countries where group O infection has been reported). Of 155 eligible subjects, 37 gave samples. By phylogenetic and serologic analysis, 32 were infected with group M (16 with subtype A, 5 with B, 7 with C, and 1 each with subtypes D, F2, G, and recombinant A/J) and 2 with group O but none with group N virus. For 3, samples could not be typed by serology or amplified by polymerase chain reaction using group M-, O-, or N-specific primers. In the United States, group O HIV infection is uncommon; no case of group N infection was found. African-born persons may have HIV strains typical of their birth country. Ongoing subtype surveillance may allow early identification of novel or emerging HIV strains.

Adult↗
PubMed2000

Serological detection of infection with diverse human and simian immunodeficiency viruses using consensus env peptides.

Cross-species transmission has been shown to play an important role in the emergence of human retroviruses. We developed a generic enzyme immunoassay using synthetic peptides from gp41 and C2V3 consensus sequences (human immunodeficiency virus [HIV] type 1 [HIV-1] groups M, O, and N and the homologous region of simian immunodeficiency virus [SIV] strains from chimpanzees [SIVcpz], SIVcpzGAB1 and SIVcpzANT) to detect divergent HIV and SIV. A cocktail of peptides from gp41 and C2V3 (M-O) detected all HIV-1 group M and O sera and showed cross-reactivity with SIVcpz sera. Further, a mixture of C2V3 peptides (GAB1-ANT) failed to detect HIV-1 infections but reacted with all SIVcpz sera, allowing discrimination of SIVcpz from HIV-1 infections. Since most SIVcpz sera cross-reacted with HIV-1 peptides, we next evaluated SIVcpz serum reactivity with rapid tests for HIV-1/2. SIVcpzANT and SIVcpzUS sera reacted with the Sero-strip and Multispot assays. Both tests are sensitive in detecting group M (97 100%, respectively), although Multispot has lower sensitivity for group O detection (67%) than does Sero-strip (100%). The limited volume and time required to perform these assays make them a generic tool for field screening. The env peptide-based assay and rapid tests should allow for the identification of emerging variants of HIV and SIV.

Animals↗
PubMed2000

Analysis of genetic variability within the immunodominant epitopes of envelope gp41 from human immunodeficiency virus type 1 (HIV-1) group M and its impact on HIV-1 antibody detection.

The serodiagnosis of human immunodeficiency virus type 1 (HIV-1) infection primarily relies on the detection of antibodies, most of which are directed against the immunodominant regions (IDR) of HIV-1 structural proteins. Among these, the N-terminal region of gp41 contains cluster I (amino acids [aa] 580 to 623), comprising the cytotoxic T-lymphocyte epitope (AVERYLKDQQLL) and the cysteine loop (CSGKLIC), and cluster II (aa 646 to 682), comprising an ectodomain region (ELDKWA). To delineate the epitope diversity within clusters I and II and to determine whether the diversity affects serologic detection by U.S. Food and Drug Administration (FDA)-licensed enzyme immunoassay (EIA) kits, gp41 Env sequences from 247 seropositive persons infected with HIV-1 group M, subtypes A (n = 42), B (n = 62), B' (n = 13), C (n = 38), D (n = 41), E (n = 18), F (n = 27), and G (n = 6), and 6 HIV-1-infected but persistently seronegative (HIPS) persons were analyzed. While all IDR were highly conserved among both seropositive and HIPS persons, minor amino acid substitutions (<20% for any one residue, mostly conservative) were observed for all subtypes, except for B', in comparison with the consensus sequence for each subtype. Most importantly, none of the observed substitutions among the group M plasma specimens affected antibody detection, since all specimens (n = 152) tested positive with all five FDA-licensed EIA kits. Furthermore, all specimens reacted with a group M consensus gp41 peptide (WGIKQLQARVLAVERYLKDQQLLGIWGCSGKLICTTAVPWNASW), and high degrees of cross-reactivity (>80%) were observed with an HIV-1 group N peptide, an HIV-1 group O peptide, and a peptide derived from the homologous region of gp41 from simian immunodeficiency virus from chimpanzee (SIVcpz). Taken together, these data indicate that the minor substitutions observed within the IDR of gp41 of HIV-1 group M subtypes do not affect antibody recognition and that all HIV-1-seropositive specimens containing the observed substitutions react with the FDA-licensed EIA kits regardless of viral genotype and geographic origin.

AIDS Serodiagnosis↗
PubMed2000

Simian immunodeficiency viruses of diverse origin can use CXCR4 as a coreceptor for entry into human cells.

Primary simian immunodeficiency virus (SIV) isolated from sooty mangabey (SIVsm [n = 6]), stumptail (SIVstm [n = 1]), mandrill (SIVmnd [n = 1]), and African green (SIVagm [n = 1]) primates were examined for their ability to infect human cells and for their coreceptor requirements. All isolates infected human peripheral blood mononuclear cells (PBMCs) from a CCR5(+/+) donor, and seven of eight isolates tested also infected CCR5(-/-) PBMCs. Analysis of coreceptor utilization using GHOST and U87 cell lines revealed that all of the isolates tested used CCR5 and the orphan receptors STRL33 and GPR15. Coreceptors such as CCR2b, CCR3, CCR8, and CX3CR1 were also utilized by some primary SIV isolates. More importantly, we found that CXCR4 was used as a coreceptor by the SIVstm, the SIVagm, and four of the SIVsm isolates in GHOST and U87 cells. These data suggest that primary SIV isolates from diverse primate species can utilize CXCR4 for viral entry, similar to what has been described for human immunodeficiency viruses.

Animals↗
PubMed2000

Use of inhibitors to evaluate coreceptor usage by simian and simian/human immunodeficiency viruses and human immunodeficiency virus type 2 in primary cells.

We have used coreceptor-targeted inhibitors to investigate which coreceptors are used by human immunodeficiency virus type 1 (HIV-1), simian immunodeficiency viruses (SIV), and human immunodeficiency virus type 2 (HIV-2) to enter peripheral blood mononuclear cells (PBMC). The inhibitors are TAK-779, which is specific for CCR5 and CCR2, aminooxypentane-RANTES, which blocks entry via CCR5 and CCR3, and AMD3100, which targets CXCR4. We found that for all the HIV-1 isolates and all but one of the HIV-2 isolates tested, the only relevant coreceptors were CCR5 and CXCR4. However, one HIV-2 isolate replicated in human PBMC even in the presence of TAK-779 and AMD3100, suggesting that it might use an undefined, alternative coreceptor that is expressed in the cells of some individuals. SIV(mac)239 and SIV(mac)251 (from macaques) were also able to use an alternative coreceptor to enter PBMC from some, but not all, human and macaque donors. The replication in human PBMC of SIV(rcm) (from a red-capped mangabey), a virus which uses CCR2 but not CCR5 for entry, was blocked by TAK-779, suggesting that CCR2 is indeed the paramount coreceptor for this virus in primary cells.

Amides↗
PubMed1999

Sustained plasma TNF-alpha and HIV-1 load despite resolution of other parameters of immune activation during treatment of tuberculosis in Africans.

OBJECTIVE: To determine the impact of treatment of tuberculosis on plasma HIV-1 load in African subjects and to correlate viral load with response to treatment and changes in immune activation. DESIGN: Clinical and microbiological responses, immune activation parameters and plasma HIV-1 load were determined in 20 patients with pulmonary tuberculosis and HIV-1 coinfection in Ghana, West Africa during the first 3 months of anti-tuberculosis treatment. METHODS: Plasma HIV-1 load and markers of immune activation were determined by commercially available assays. Human leukocyte antigen (HLA)-DR incorporation into the HIV-1 envelope was measured by using an immunomagnetic capture technique. RESULTS: Treatment of tuberculosis resulted in significant improvements in weight and haemoglobin, a high sputum smear conversion rate and marked reductions in mean plasma tumour necrosis factor (TNF) receptor-1, interleukin-6 and C-reactive protein. Furthermore, incorporation of host HLA-DR into the HIV-1 envelope decreased; this also suggested a reduction in immune activation of the cells supporting viral replication. However, of importance with regard to AIDS pathogenesis, neither mean plasma TNF-alpha nor HIV-1 load decreased significantly. CONCLUSIONS: The failure of HIV-1 plasma load to decline significantly during the initial months of anti-tuberculosis treatment is associated with high, sustained systemic levels of TNF-alpha. The dissociation between the sustained levels of plasma TNF-alpha and the major reductions in other, diverse immune activation parameters may represent dysregulation of cytokine production in these African patients.

AIDS-Related Opportunistic Infections↗
PubMed1999

Partial resistance to infection by R5X4 primary HIV type 1 isolates in an exposed-uninfected individual homozygous for CCR5 32-base pair deletion.

It is known that certain individuals remain persistently seronegative despite repeated exposure to HIV-1. Studies have shown that some exposed uninfected (EU) individuals who are homozygous for a 32-bp deletion in the CCR5 gene are resistant to infection with non-syncytium-inducing (R5) viruses. In the present investigation, we provide evidence that a highly exposed-uninfected individual with the CCR5 32-bp deletion (EUdelta32-1) also has partial resistance to syncytium-inducing (R5X4) HIV-1 viruses, when compared with unexposed-uninfected individuals with (UUdelta32-1 and UUdelta32-2) and without (UU-1 and UU-2) the 32-bp deletion. The partial resistance of EU cells was due neither to altered coreceptor expression, nor to specific mutation or deletion in the coding region of chemokine coreceptors CXCR4 and CCR3. While SDF-1, the ligand for CXCR4, blocked entry of R5X4 viruses to a similar extent in EUdelta32 and UUdelta32, there was a differential production of soluble factors by EUdelta32. Both CD4+ and CD8+ cells from EUdelta32-1 produced soluble factors that efficiently suppressed infection by HIV-1 R5X4 viruses when compared with supernatant from UUdelta32. These data provide evidence that additional soluble factors are involved in resistance to infection with R5X4 viruses.

CD4-Positive T-Lymphocytes↗
PubMed1999

Persistently negative HIV-1 antibody enzyme immunoassay screening results for patients with HIV-1 infection and AIDS: serologic, clinical, and virologic results. Seronegative AIDS Clinical Study Group.

OBJECTIVE: To describe persons with HIV infection and AIDS but with persistently negative HIV antibody enzyme immunoassay (EIA) results. DESIGN: Surveillance for persons meeting a case definition for HIV-1-seronegative AIDS. SETTING: United States and Canada. PATIENTS: A total of eight patients with seronegative AIDS identified from July 1995 through September 1997. MAIN OUTCOME MEASURES: Clinical history of HIV disease, history of HIV test results, and CD4 cell counts from medical record review; results of testing with a panel of EIA for antibodies to HIV-1, and HIV-1 p24 antigen; and viral subtype. RESULTS: Negative HIV EIA results occurred at CD4 cell counts of 0-230 x 10(6)/l, and at HIV RNA concentrations of 105,000-7,943,000 copies/ml. Using a panel of HIV EIA on sera from three patients, none of the HIV EIA detected infection with HIV-1, and signal-to-cut-off ratios were < or = 0.8 or all test kits evaluated. Sera from five patients showed weak reactivity in some HIV EIA, but were non-reactive in other HIV EIA. All patients were infected with HIV-1 subtype B. CONCLUSIONS: Rarely, results of EIA tests for antibodies to HIV-1 may be persistently negative in some HIV-1 subtype B-infected persons with AIDS. Physicians treating patients with illnesses or CD4 cell counts suggestive of HIV infection, but for whom results of HIV EIA are negative, should consider p24 antigen, nucleic acid amplification, or viral culture testing to document the presence of HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Absence of human T-lymphotropic virus type I tax sequences in a population of normal blood donors in the Baltimore, MD/Washington, DC, area: results from a multicenter study.

BACKGROUND: It was reported recently that sequences corresponding to the human T-lymphotropic virus type I (HTLV-I) tax gene were detected in peripheral blood mononuclear cells from 8 to 11 percent of healthy blood donors without detectable antibodies to HTLV-I. A multicenter blind study was conducted to determine if these results could be independently confirmed. STUDY DESIGN AND METHODS: Specimens were collected from 100 anti-HTLV-I-negative healthy blood donors and from 11 anti-HTLV-I- or anti-HTLV-II-positive individuals. All samples were coded and distributed to each of four independent testing laboratories for polymerase chain reaction analysis to detect sequences of the HTLV-I or HTLV-II tax gene, using detailed procedures specified by the laboratory reporting the original observation. Each laboratory also tested a dilution panel of a plasmid containing HTLV-I tax to determine the analytical sensitivity of the procedure. RESULTS: The analytical sensitivity of the screening methods permitted detection of as few as 1 to 10 copies of the tax gene. However, HTLV-I tax sequences could not be detected in any of the anti-HTLV-I-negative blood donors at more than one test site. CONCLUSION: HTLV-I tax sequences appear not to be present in this population of 100 blood donors negative for anti-HTLV-I.

Adult↗
PubMed1999

Effect of immune activation induced by Cryptosporidium parvum whole antigen on in vitro human immunodeficiency virus type 1 infection.

Previous epidemiologic investigations have suggested that persons with AIDS who are infected with Cryptosporidium parvum have a shorter survival time than those with other opportunistic infections. In this study, the effect of immune activation by a crude Cryptosporidium whole antigen on human immunodeficiency virus type 1 (HIV-1) infection was evaluated. Peripheral blood mononuclear cells from healthy persons without HIV-1 infection had increased proliferative and cytokine (interleukin-4, interferon-gamma, and tumor necrosis factor [TNF]-alpha) responses to stimulation with the crude Cryptosporidium whole antigen. This stimulation increased HIV-1 p24 antigen production in in vitro infection by>30-fold. A similar increase in p24 production was also seen when stimulation was done after cells were infected with HIV-1. Neutralization of TNF-alpha reduced Cryptosporidium antigen-induced p24 production by >50%. Results of this study suggest that Cryptosporidium-induced immune activation may be a cofactor in regulating HIV-1 production.

Animals↗
PubMed1999

Involvement of matrix metalloproteinases in human immunodeficiency virus type 1-induced replication by clinical Mycobacterium avium isolates.

The role of Mycobacterium avium isolates in modulating human immunodeficiency virus type 1 (HIV-1) replication was examined by use of an in vitro, resting T cell system. Two human clinical isolates (serotypes 1 and 4) but not an environmental M. avium isolate (serotype 2) enhanced HIV-1 replication. The M. avium-induced HIV-1 replication was not associated with cell activation or differential cytokine production or utilization. Addition of matrix metalloproteinase (MMP) inhibitors and their in vivo regulators, tissue inhibitors of metalloproteinases-1 and -2, abrogated M. avium-induced HIV-1 replication 80%-95%. The MMP inhibitors did not have any effect on the HIV-1 protease activity, suggesting that they may affect cellular processes. Furthermore, MMP-9 protein was differentially expressed after infection with clinical M. avium isolates and paralleled HIV-1 p24 production. Collectively, these data suggest that M. avium-induced HIV-1 replication is mediated, in part, through the induction of MMP-9.

Animals↗
PubMed1999

Viral and immunologic examination of human immunodeficiency virus type 1-infected, persistently seronegative persons.

Persons who were human immunodeficiency virus type 1 (HIV-1)-infected but who remained persistently seronegative (HIPS) on HIV-1 antibody tests were examined through AIDS case surveillance. Six such individuals (HIPS-1 to -4, -7, and -9) were examined to determine whether their persistent seronegativity was attributable to immune dysfunction or infection with atypical HIV. Of the 6, 4 had antibody titers to at least 1 other common pathogen. In vitro stimulation of peripheral blood mononuclear cells from HIPS-4 and HIPS-7 with pokeweed mitogen or phosphorothioate oligodeoxynucleotide (direct B cell mitogen) did not produce HIV-1-specific antibody. Reconstitution experiments with recombinant interleukin (rIL)-4 and rIL-12 also had no impact on antibody production. Virus isolates from HIPS-4 and -9 were R5X4-tropic, whereas HIPS-7 was CCR5-tropic only. Sequence analysis of long terminal repeat, p24, and env gp41 did not reveal any specific mutation, and phylogenetic analysis confirmed that all 6 virus specimens were HIV-1 subtype B. These data suggest that the lack of a detectable antibody response in these patients may be the result of immune dysfunction.

Amino Acid Sequence↗
PubMed1999

Modulation of T-cell responses to a recall antigen in human T-cell leukemia virus type 1-infected individuals.

To determine the mechanism of the purified protein derivative (PPD)-specific hyporesponsiveness in Mycobacterium bovis BCG-vaccinated human T-cell leukemia virus type 1 (HTLV-1)-infected individuals, we examined cytokine production in response to PPD in the following four groups of individuals: (i) HTLV-negative, PPD nonresponders (n = 11; NN); (ii) HTLV-negative, PPD responders (n = 18; NP); (iii) HTLV-positive, PPD nonresponders (n = 15; PN); and (iv) HTLV-positive, PPD responders (n = 15; PP). In vitro stimulation with PPD resulted in both proliferative responses and gamma interferon (IFN-gamma) production in NP and PP (P < 0.02), with minimal proliferation and IFN-gamma production in the NN and PN groups. Further, PPD-specific interleukin 10 (IL-10) production was significantly reduced in the PN group (P < 0.01), while the other groups had comparable levels. Cytokine reconstitution experiments demonstrated that while addition of recombinant IL-12 (rIL-12) plus anti-IL-4 restored PPD-specific responses in the NN group, it had no effect in the PN group. However, addition of rIL-12 resulted in the increased production of IFN-gamma in both nonresponder groups (NN and PN), suggesting that the lack of IFN-gamma production was not responsible for the PPD anergy. We conclude that PPD-specific anergy in HTLV-1-infected individuals appears to be due in part to their inability to respond to rIL-12.

Antigens, Bacterial↗
PubMed1999

Observed differences in virulence-associated phenotypes between a human clinical isolate and a veterinary isolate of Mycobacterium avium.

Mycobacterium avium, the most common opportunistic pathogen in patients with AIDS, is frequently isolated from a variety of environmental sources, but rarely can these environmental isolates be epidemiologically linked with isolates known to cause human disease. Using a number of in vitro tissue culture assays, we found significant pathogenic differences between a serotype 4 human clinical M. avium isolate and a serotype 2 veterinary isolate. Cell association of the patient strain with a human intestinal cell line was 1.7 times that of the veterinary strain. Growth of this clinical strain in human peripheral blood mononuclear cell-derived macrophages increased from 12-fold higher than that of the veterinary isolate after 2 days to 200-fold higher after 4 days. By the conclusion of each experiment, lysis of all examined host cell types and accumulation of cell debris were observed in infections with the human isolate, but monolayers remained relatively intact in the presence of the animal isolate. The two strains also differed in the ability to stimulate human immunodeficiency virus replication in coinfected host cells, with p24 antigen levels after 6 days threefold higher in the cells coinfected with the clinical strain than in those infected with the veterinary strain. If the genetic differences responsible for the phenotypes observed in these assays can be identified and characterized, it may be possible to determine which M. avium strains in the environment are potential human pathogens.

Animals↗
PubMed1999

Detection of phylogenetically diverse human immunodeficiency virus type 1 groups M and O from plasma by using highly sensitive and specific generic primers.

The high degree of genetic diversity within human immunodeficiency virus type 1 (HIV-1), which includes two major groups, M (major) and O (outlier), and various env subtypes within group M (subtypes A to J), has made designing assays that will detect all known HIV-1 strains difficult. We have developed a generic primer set based on the conserved immunodominant region of transmembrane protein gp41 that can reliably amplify as few as 10 copies/PCR of viral DNA from near-full-length clones representing group M subtypes A to H (subtypes I and J were not available). The assay is highly sensitive in detecting plasma viral RNA from HIV-1 strains of diverse geographic origins representing different subtypes of HIV-1 group M as well as HIV-1 group O. Of the 253 group M plasma specimens (subtypes A, 68 specimens; B, 71; C, 19; D, 27; E, 23; F, 33; and G, 12), 250 (98.8%) were amplified by using the gp41 M/O primer set. More importantly, all 32 (100%) group O plasma samples were also amplified with these primers. In vitro spiking experiments further revealed that the assay could reliably detect as few as 25 copies/ml of viral RNA and gave positive signals in HIV-1-seropositive specimens with plasma copy numbers below the limits of detection by all commercially available viral load assays. In addition, analysis of five seroconversion panels indicated that the assay is highly sensitive for early detection of plasma viremia during the "window period." Thus, the highly sensitive assay will be useful for early detection of HIV-1 in clinical specimens from all known HIV-1 infections, regardless of their genotypes and geographic origins.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Adaptation to promiscuous usage of CC and CXC-chemokine coreceptors in vivo correlates with HIV-1 disease progression.

OBJECTIVE: To study coreceptor usage of sequential primary HIV-1 isolates in a longitudinal follow-up cohort of HIV-1-infected men to understand its contribution to pathogenesis of HIV disease. DESIGN: Viral coreceptor usage of sequential primary isolates from HIV-1-infected individuals was examined at various timepoints and data was compared with CD4 cell counts, rates of disease progression and beta-chemokine production. METHODS: Fifty-eight sequential primary isolates were obtained from four rapid progressors, six late progressors, and three long-term nonprogressors (LTNP) and their coreceptor usage was examined by infection of peripheral blood mononuclear cells (PBMC) from donors with wild-type or non-functional CC-chemokine receptor (CCR)-5, and by infection of GHOST4 cells expressing CD4 and various chemokine receptors [CCR-1-CCR-5, CXC-chemokine receptor (CXCR)-4, BOB/GPR15, BONZO/STRL33]. Production of RANTES and macrophage inflammatory protein (MIP)-1beta was examined using unstimulated or phytohemagglutinin (PHA)-stimulated PBMC isolated from these individuals at multiple timepoints during infection. RESULTS: A switch from single CCR-5 coreceptor usage to multiple coreceptor usage occurred in all four rapid progressors and three out of six late progressors. In addition to the commonly used coreceptors CXCR-4, CCR-5, and CCR-3, some of the viruses isolated from patients in the terminal stage of infection also used CCR-1, CCR-2b, CCR-4, and BOB as coreceptors. The emergence of viral variants capable of utilizing multiple coreceptors generally preceded CD4 cell decline to < 200 x 10(6)/l and correlated with the onset of AIDS. In contrast, three LTNP maintained exclusive usage of CCR-5 over a period of 7-12 years post-infection. Endogenous production of RANTES and MIP-1beta by PBMC from LTNP was not significantly different from rapid and late progressors. However, PHA-driven production of both chemokines was significantly higher in LTNP, suggesting that in vivo activating stimuli might curtail HIV replication by inducing these chemokines. CONCLUSIONS: Viral variants capable of utilizing a broad range of coreceptors correlated with HIV-1 disease progression. In contrast, LTNP maintain exclusive usage of CCR-5 and produce higher levels of beta-chemokines. Thus, both viral and host determinants leading to the emergence of viral variants capable of using an expanded range of coreceptors may be likely determinants of disease progression.

Adaptation, Physiological↗