Isolates In Peripheral Blood Mononuclear Cells Research Articles

Новая стратегия поиска гормональной терапии пролиферативных процессов эндометрия у пациенток в постменопаузе

The limited efficacy of hormone therapy for endometrial proliferative process (EPP) in postmenopausal patients and its side effects on the immune system functionalities have not been studied in detail. Here we assess the feasibility of hormone therapy for EPP in postmenopausal patients through evaluation of estradiol and progesterone receptor gene expression in endometrial tissue and peripheral blood mononuclear cells (PBMC). The study enrolled 92 postmenopausal patients with EPP, including 37 pts with glandular-fibrous polyps, 7 pts with non-atypical endometrial hyperplasia (EH), 8 pts with atypical endometrial hyperplasia (AEH), 31 pts with moderately differentiated adenocarcinoma and 9 pts with highly differentiated adenocarcinoma. The PBMC isolates and endometrial samples were tested for ER⍺, ERβ, mER, PRA, PRB, mPR and PGRmC1 expression by reverse real time polymerase chain reaction (RT–PCR). Differential changes in PBMC receptor profiles upon in vitro exposure to progesterone or mifepristone were determined for patients with endometrial polyps and healthy women. The results indicate elevated expression of ERα, ERβ, PRA, PRB, mPR and PGRmC1 by endometrial tissues in EH and elevated expression of mER, ER⍺ and PRA by PBMC in AEH, apparently reflecting suppressed functionalities of monocytes, macrophages, Т-cells and natural killer cells. Unaltered expression of the studied genes by PBMC in endometrial adenocarcinoma may reflect the incrementing tumor autonomy. In vitro, mifepristone inhibited ER⍺, ERβ, mPR, PGRmC1, PRA and PRB expression in PBMC isolated from patients with endometrial polyps. We suppose that such effects can mitigate the negative influence of sex steroid hormones on immunocompetent cells.

Neutralizing Activity of Broadly Neutralizing Anti-HIV-1 Antibodies against Clade B Clinical Isolates Produced in Peripheral Blood Mononuclear Cells.

ABSTRACTRecently discovered broadly neutralizing antibodies (bNAbs) against HIV-1 demonstrate extensive breadth and potency against diverse HIV-1 strains and represent a promising approach for the treatment and prevention of HIV-1 infection. The breadth and potency of these antibodies have primarily been evaluated by using panels of HIV-1 Env-pseudotyped viruses produced in 293T cells expressing molecularly cloned Env proteins. Here we report on the ability of five bNAbs currently in clinical development to neutralize circulating primary HIV-1 isolates derived from peripheral blood mononuclear cells (PBMCs) and compare the results to those obtained with the pseudovirus panels used to characterize the bNAbs. The five bNAbs demonstrated significantly less breadth and potency against clinical isolates produced in PBMCs than against Env-pseudotyped viruses. The magnitude of this difference in neutralizing activity varied, depending on the antibody epitope. Glycan-targeting antibodies showed differences of only 3- to 4-fold, while antibody 10E8, which targets the membrane-proximal external region, showed a nearly 100-fold decrease in activity between published Env-pseudotyped virus panels and PBMC-derived primary isolates. Utilizing clonal PBMC-derived primary isolates and molecular clones, we determined that the observed discrepancy in bNAb performance is due to the increased sensitivity to neutralization exhibited by 293T-produced Env-pseudotyped viruses. We also found that while full-length molecularly cloned viruses produced in 293T cells exhibit greater sensitivity to neutralization than PBMC-derived viruses do, Env-pseudotyped viruses produced in 293T cells generally exhibit even greater sensitivity to neutralization. As the clinical development of bNAbs progresses, it will be critical to determine the relevance of each of these in vitro neutralization assays to in vivo antibody performance.IMPORTANCE Novel therapeutic and preventive strategies are needed to contain the HIV-1 epidemic. Antibodies with exceptional neutralizing activity against HIV-1 may provide several advantages to traditional HIV drugs, including an improved side-effect profile, a reduced dosing frequency, and immune enhancement. The activity of these antibodies has been established in vitro by utilizing HIV-1 Env-pseudotyped viruses derived from circulating viruses but produced in 293T cells by pairing Env proteins with a backbone vector. We tested PBMC-produced circulating viruses against five anti-HIV-1 antibodies currently in clinical development. We found that the activity of these antibodies against PBMC isolates is significantly less than that against 293T Env-pseudotyped viruses. This decline varied among the antibodies tested, with some demonstrating moderate reductions in activity and others showing an almost 100-fold reduction. As the development of these antibodies progresses, it will be critical to determine how the results of different in vitro tests correspond to performance in the clinic.

Abstract 471: Detection of circulating tumor cells in high-risk primary uveal melanoma by the photoacoustic method

Abstract Circulating tumor cells (CTCs) have been shown to be a prognostic marker in breast cancer1. We hypothesize that circulating melanoma cell (CMC) detection could be utilized in the management of uveal melanoma, including early intervention. Prior methodologies for circulating uveal melanoma cell (CUMC) detection have been fraught with poor sensitivity, limiting their clinical utility2. Development of an improved method is necessary to establish the clinical utility of CUMC monitoring. Photoacoustics, also referred to as laser-induced ultrasound, is a novel platform for the detection and capture of CMCs. Photoacoustics uses short duration pulsed light to create ultrasonic acoustic waves in an optically absorbing medium, in this case melanin within melanoma3. As light is absorbed by irradiated chromophores, the optical energy gets converted into kinetic thermal energy trapped within the chromophore and subsequent thermal expansion ensues. Transient thermoelastic expansion of the absorbent cell results in the propagation of ultrasonic acoustic waves which can be detected and analyzed using a piezoelectric response mechanism. In addition, detected CMCs can be isolated by a two-phase flow cell separation technique4. Due to the low cost and melanoma specific capabilities of photoacoustics, we evaluated this technology for the purpose of CUMC detection. Methods: Cells from uveal melanoma cell line UM002B, established at Thomas Jefferson, were titrated to various cell concentrations and analyzed in a neutral density solution utilizing the photoacoustic method. Uveal melanoma cells of differing concentrations were spiked into isolated healthy donor peripheral blood mononuclear cells (PBMCs) and healthy whole blood samples. PBMC isolates were analyzed for CUMCs. Results: CUMCs were successfully quantified by the photoacoustic method including single cell detection. Recovery rates of cultured cells in a neutral density solution approached 25%. Recovery rates for CUMCs in whole blood averaged 10% of expected cell yield (56/540 cells detected) with a higher detection rate at lower cell concentrations. Photoacoustics offers a viable method for the detection of CUMCs with an accuracy that meets or exceeds previously reported CUMC yields. Studies analyzing CUMCs from patients with metastatic disease are ongoing. 1. Cristofanilli, M, et al., Circulating tumor cells, disease progression, and survival in metastatic breast cancer. N Engl J Med, 2004. 351(8): 781-91. 2. Bidard FC, et al., Detection rate and prognostic value of circulating tumor cells and circulating tumor DNA in metastatic uveal melanoma. Int J Cancer. 2014 Mar 1;134(5):1207-13. 3. Weight RM, et al. Photoacoustic detection of metastatic melanoma cells in the human circulatory system. Opt Lett. 2006 Oct 15;31(20):2998-3000. 4. O’Brien CM, et al. Capture of circulating tumor cells using photoacoustic flowmetry and two phase flow. J Biomed Opt. 2012 Jun;17(6):061221. Citation Format: Ryan M. Weight, Shingo Sato, Masahiro Ohara, Mizue Terai, Michael Mastrangelo, Marlana Orloff, Benjamin Goldschmidt, John Viator, Takami Sato. Detection of circulating tumor cells in high-risk primary uveal melanoma by the photoacoustic method. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 471.

Assessing the Effect of Orally Administered <I>Echinacea purpurea</I> Extracts vs. Placebo on Pro-Inflammatory Cytokine Responses <I>Ex Vivo</I>

Objective: To determine if aqueous, polysaccharide-containing Echinacea purpurea extracts taken orally increase pro-inflammatory cytokine responses ex vivo. Design: In two separate studies, the levels of TNF-alpha (TNF), interleukins 2 and 6 (IL-2 and IL-6) and interferon gamma (IFN-γ) secreted by phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) from healthy adults randomized to take one of three E. purpurea formulations or placebo orally for 10 consecutive days were measured. Blood was obtained from participants at baseline and on days 2, 3, 7, and 10 while on study medication. PBMC were isolated and stimulated with PHA for 24 h, and supernatants collected for measurement of pro-inflammatory cytokine levels.Outcome Measures: Primary outcomes were peak concentrations of PHA-induced TNF, IL-2, IL-6, and IFN-γ from PBMC isolates collected while on study medication. Cytokine responses of PBMC from participants randomized to one of the Echinacea formulations were compared with those of placebo recipients by regression analysis.Results: Cytokine levels were obtained from mitogen-activated PBMC from 86 participants, collected while on study medication. No significant differences in the peak levels of PBMC-secreted TNF, IL-2, IL-6 and IFN-γ were observed between PBMC from those taking active Echinacea preparation vs. a placebo. After adjusting for age, a trend toward increased IL-6 secreted by PHA-stimulated PBMC isolated on day 3 of oral administration was observed for the group taking one of the E. purpurea formulations compared with placebo (P=0.064).Conclusions: Oral administration of E. purpurea did not significantly enhance peak pro-inflammatory cytokine responses in mitogen-stimulated PBMC.

Differential cytokine expression profile in peripheral blood mononuclear cells of endometritic buffaloes

The aim of present study was to elucidate the relative mRNA expression of certain cytokines, viz. interleukin- 1ß (IL-1ß), IL-8, tumor necrosis factor alpha (TNFa) and IL-4 in peripheral blood mononuclear cells (PBMCs) of endometritic buffaloes. Out of 15 buffaloes, 9 buffaloes were diagnosed positive for endometritis whereas 6 buffaloes having no symptoms of endometritis were considered as healthy control. The blood samples were collected from each animal during diagnosis of endometritis and PBMCs were separated from collected blood samples by density gradient centrifugation. Total RNA was extracted from the cultured PBMCs isolates, reverse transcribed to synthesize the cDNA and amplified in real time PCR system. The relative fold of expression was estimated using 2-∆∆Ct method. An up-regulation in all 3 pro-inflammatory cytokines (IL-1ß, IL-8 and TNFa) mRNA, ranging from 1.92 to 3.27 fold was observed in buffaloes with endometritis as compared to healthy. However, no alteration was detected in anti-inflammatory cytokine, IL-4 expression. Thus, it is concluded that certain cytokines expressed differentially in PBMCs in buffaloes with endometritis, that is first ever information in this species. Nevertheless, further research in respect to threshold level of each target cytokine in peripheral circulation involving more number of animals is required to establish these potential marker gene(s) for diagnosis of endometritis and for monitoring of new therapeutic approaches.

Inhibiting Early-Stage Events in HIV-1 Replication by Small-Molecule Targeting of the HIV-1 Capsid

The HIV-1 capsid (CA) protein plays essential roles in both early and late stages of virl replication and has emerged as a novel drug target. We report hybrid structure-based virtual screening to identify small molecules with the potential to interact with the N-terminal domain (NTD) of HIV-1 CA and disrupt early, preintegration steps of the HIV-1 replication cycle. The small molecule 4,4'-[dibenzo[b,d]furan-2,8-diylbis(5-phenyl-1H-imidazole-4,2-diyl)]dibenzoic acid (CK026), which had anti-HIV-1 activity in single- and multiple-round infections but failed to inhibit viral replication in peripheral blood mononuclear cells (PBMCs), was identified. Three analogues of CK026 with reduced size and better drug-like properties were synthesized and assessed. Compound I-XW-053 (4-(4,5-diphenyl-1H-imidazol-2-yl)benzoic acid) retained all of the antiviral activity of the parental compound and inhibited the replication of a diverse panel of primary HIV-1 isolates in PBMCs, while displaying no appreciable cytotoxicity. This antiviral activity was specific to HIV-1, as I-XW-053 displayed no effect on the replication of SIV or against a panel of nonretroviruses. Direct interaction of I-XW-053 was quantified with wild-type and mutant CA protein using surface plasmon resonance and isothermal titration calorimetry. Mutation of Ile37 and Arg173, which are required for interaction with compound I-XW-053, crippled the virus at an early, preintegration step. Using quantitative PCR, we demonstrated that treatment with I-XW-053 inhibited HIV-1 reverse transcription in multiple cell types, indirectly pointing to dysfunction in the uncoating process. In summary, we have identified a CA-specific compound that targets and inhibits a novel region in the NTD-NTD interface, affects uncoating, and possesses broad-spectrum anti-HIV-1 activity.

Consistent detection of bovine papillomavirus in lesions, intact skin and peripheral blood mononuclear cells of horses affected by hoof canker

Equine hoof canker is a chronic proliferative pododermatitis of as yet unknown aetiology. Like equine sarcoid disease, canker is a therapy-resistant disorder characterised by hyperkeratosis, acanthosis and a marked tendency to recur. There is an association of sarcoid-inducing bovine papillomaviruses of types 1 and 2 (BPV-1, BPV-2) with hoof canker disease. Using PCR-based techniques, we assessed canker tissue, intact skin and/or peripheral blood mononuclear cells (PBMCs) of 25 canker-affected horses for the presence of sarcoid-associated BPV-1 and -2. Conventional PCR revealed BPV-1/-2 DNA in 24/24 canker, 12/13 skin and 10/11 PBMC DNA isolates. Using inverse PCR, full-length BPV episomes were detected in 1/5 canker specimens. Sequencing of viral early and late genes amplified from canker, intact skin and PBMC DNA of 2 cases revealed an overall identity of 98% to BPV-1. Viral DNA loads amounted to ≤16 copies per cell in canker tissue and intact skin, and to ≤0.35 copies per PBMC, as determined by quantitative PCR. Using RT-PCR, the viral major oncogene E5 was shown to be transcribed in 2/4 canker tissue specimens and 5/7 PBMC isolates. Immunocapture PCR from 7 canker and 6 skin extract supernatants revealed capsomere-associated viral DNA in one canker and one skin sample. Hoof tissue, skin and PBMCs collected from 13 individuals with no signs of canker or BPV-related malignancies scored negative throughout the experiments. These findings suggest that the observed presence of BPV-1/-2 in canker-affected horses is not coincidental but indicative of an active contribution to hoof canker disease. The use of antivirals and/or immune modulators may help improving canker therapy.

Comparison of Envelope 2 CD81 binding regions in PBMC-derived versus serum-derived hepatitis C virus isolates: higher conservation of CD81 region 2 in PBMC isolates

The aim of the present study was to investigate the variability of hepatitis C virus (HCV) CD81 binding regions (CD81-1/2) in peripheral blood mononuclear cells (PBMC)-derived and serum-derived HCV-RNA samples. HCV-RNA was isolated from PBMC (10⁴ cells) and serum samples from 37 patients chronically infected with HCV genotype 1a/1b (n=21/16). The hypervariable regions 1/2 (amino acid 384-410, amino acid 474-482) and regions CD81-1/2 (amino acid 474-494, amino acid 522-551) were analysed. Mutational frequency of amino acid sequences was compared between PBMC-derived and serum-derived HCV variants as well as local accumulation of mutations. Furthermore, CD81 was quantified on PBMC. Mutational frequency was not different between PBMC-derived and serum-derived HCV variants. A trend to lower mutational frequency in genotype 1a PBMC variants compared with serum-derived variants was observed in region CD81-2 (5%vs 10%). Smoothed mutational frequency analysis showed a significantly lower variability within genotype 1a CD81-2 in PBMC-derived compared to serum-derived HCV-RNA (P=0.026). CD81 expression on PBMC was not correlated with the number of mutations within the CD81 binding regions. A higher conservation was observed in region CD81-2 in PBMC-derived versus serum-derived HCV-RNA indicating selection of HCV variants on PBMC. The variability in the CD81 binding regions appeared to be independent from CD81 expression.

Cellulose Acetate 1,2-Benzenedicarboxylate Inhibits Infection by Cell-Free and Cell-Associated Primary HIV-1 Isolates

Cellulose acetate 1,2-benzenedicarboxylate (CAP), a pharmaceutical excipient used for enteric film coating of capsules and tablets, was previously shown to have potent inhibitory activity against infection by human immunodeficiency virus type 1 (HIV-1) T cell line-adapted (TCLA) strains. In the present study, we determined the inhibitory activity of CAP against infection by cell-free and cell-associated primary HIV-1 isolates with distinct genotypes and biotypes in cervical explants, peripheral blood mononuclear cells (PBMCs), monocytederived macrophages (MDMs), and CEMx174 5.25M7 cells. CAP blocked infection by cell-free and cell-associated HIV-1 in cervical explants. It inhibited infection by cell-free primary HIV-1 isolates (clades A to G and group O) in PBMCs, MDMs, and CEMx174 5.25M7 cells and blocked transmissions of the cell-associated primary HIV-1 isolates from dendritic cells (DCs) to PBMCs, from MDMs to PBMCs, and from PBMCs to CEMx174 5.25M7 cells. The inhibitory activity of CAP on infection by the cell-free and cell-associated primary HIV-1 isolates is independent of viral subtypes and coreceptor usage. These data suggest that CAP is a good microbicide candidate that can be further developed for preventing sexual transmission of HIV-1.

Inhibition of Human Immunodeficiency Virus Replication by a Dual CCR5/CXCR4 Antagonist

Here we report that the N-pyridinylmethyl cyclam analog AMD3451 has antiviral activity against a wide variety of R5, R5/X4, and X4 strains of human immunodeficiency virus type 1 (HIV-1) and HIV-2 (50% inhibitory concentration [IC(50)] ranging from 1.2 to 26.5 microM) in various T-cell lines, CCR5- or CXCR4-transfected cells, peripheral blood mononuclear cells (PBMCs), and monocytes/macrophages. AMD3451 also inhibited R5, R5/X4, and X4 HIV-1 primary clinical isolates in PBMCs (IC(50), 1.8 to 7.3 microM). A PCR-based viral entry assay revealed that AMD3451 blocks R5 and X4 HIV-1 infection at the virus entry stage. AMD3451 dose-dependently inhibited the intracellular Ca(2+) signaling induced by the CXCR4 ligand CXCL12 in T-lymphocytic cells and in CXCR4-transfected cells, as well as the Ca(2+) flux induced by the CCR5 ligands CCL5, CCL3, and CCL4 in CCR5-transfected cells. The compound did not interfere with chemokine-induced Ca(2+) signaling through CCR1, CCR2, CCR3, CCR4, CCR6, CCR9, or CXCR3 and did not induce intracellular Ca(2+) signaling by itself at concentrations up to 400 microM. In freshly isolated monocytes, AMD3451 inhibited the Ca(2+) flux induced by CXCL12 and CCL4 but not that induced by CCL2, CCL3, CCL5, and CCL7. The CXCL12- and CCL3-induced chemotaxis was also dose-dependently inhibited by AMD3451. Furthermore, AMD3451 inhibited CXCL12- and CCL3L1-induced endocytosis in CXCR4- and CCR5-transfected cells. AMD3451, in contrast to the specific CXCR4 antagonist AMD3100, did not inhibit but enhanced the binding of several anti-CXCR4 monoclonal antibodies (such as clone 12G5) at the cell surface, pointing to a different interaction with CXCR4. AMD3451 is the first low-molecular-weight anti-HIV agent with selective HIV coreceptor, CCR5 and CXCR4, interaction.

A novel virus capture assay reveals a differential acquisition of host HLA-DR by clinical isolates of human immunodeficiency virus type 1 expanded in primary human cells depending on the nature of producing cells and the donor source

Previous findings indicated that HLA-DR is probably one of the most abundant cellular constituents incorporated within the human immunodeficiency virus type 1 (HIV-1) envelope. Given that the life-cycle of HIV-1 has been reported to be modulated by virion-bound host HLA-DR, an improved version of a virus capture technique was developed to assess the degree of HLA-DR incorporation in several clinical isolates of HIV-1 derived from primary human peripheral blood mononuclear cells (PBMCs) and monocyte-derived macrophages (MDM). Analysis of virus stocks purified from PBMCs and MDM indicated that primary isolates of HIV-1 bearing distinct tropism (i.e. T-, macrophage-, and dual-tropic) all incorporate host cell membrane HLA-DR protein. The amount of incorporated HLA-DR varies among the primary HIV-1 isolates tested. Propagation of some clinical HIV-1 isolates in either autologous PBMCs or MDM resulted in differential incorporation of virion-bound cellular HLA-DR depending on the nature of the virus producer cells. Differences in the degree of HLA-DR incorporation were also noticed when macrophage-tropic isolates of HIV-1 were produced in MDM from different donors. Altogether these data show that the efficiency of HLA-DR incorporation into the envelope of primary isolates of HIV-1 is a multifactorial phenomenon since it is affected by the virus isolate itself, the nature of host cells (i.e. PBMCs or MDM) and the donor source.

Interferon-beta induces selective enhancement of antigen-specific T cell responses.

Interferon-beta (IFN-beta) inhibits mitogen-induced T cell responses, in part through downregulation of interleukin-12 (IL-12) or upregulation of IL-10. We have reexamined these findings using ragweed (RW) stimulated or tetanus toxoid (TT)-stimulated human peripheral blood mononuclear cells (PBMC) and nontransformed, antigen-specific, human Th0, Th1, and Th2 clones. IFN-beta induced concentration-dependent inhibition of phytohemagglutinin (PHA)-stimulated PBMC proliferation and enhancement of RW-stimulated or TTstimulated PBMC proliferation. Monocyte depletion of PBMC isolates resulted in concentration-dependent inhibition of RW-driven or TT-driven proliferation by IFN-beta. This response was unaltered by the addition of either exogenous recombinant human IL-12 (rHuIL-12) or saturating concentrations of anti-IL-10. Moreover, addition of exogenous rHuIL-10 to nondepleted RW-driven or TT-driven PBMC cultures did not alter the concentration-dependent enhancement of antigen-driven proliferation induced by IFN-beta. Th0, Th1, and Th2 clones stimulated in the presence of antigen and autologous, irradiated PBMC displayed concentration-dependent inhibition of proliferation in the presence of IFN-beta that was unaltered by the addition of either exogenous rHuIL-12 or a saturating concentration of anti-IL-10. Finally, whereas IFN-beta inhibited antigen-driven generation of IL-5, IL-12, IL-13, and IFN-gamma, IFN-beta enhanced generation of both IL-4 and IL-10. Thus, IFN-beta, induces a selective, IL-10-independent and IL-12-independent upregulation of antigen-specific T cell responses, supporting the role of IFN-beta as an immunomodulatory rather than an antiproliferative/immunosuppressive cytokine.

Complement-mediated enhancement of HIV-1 infection in peripheral blood mononuclear cells.

We investigated if complement-mediated enhancement of HIV infection occurs in peripheral blood mononuclear cells (PBMC). In 7 experiments, we evaluated the effect of human complement on HIVIIIB infection in vitro. We measured HIV antigen production on day 4 and found that pre-incubation of HIV with complement led to enhanced production of antigen with a median enhancement of 2.5-fold (range 1.1-6.8). This complement-mediated increase in antigen production was statistically significant (p < 0.02). Complement-mediated enhancement of HIV infection was also tested in CD4 cells enriched from PBMC, and CD4 cells persistently gave higher levels of infection enhancement than PBMC. Thus, CD4 cells appear to be sufficient for complement-mediated enhancement of HIV infection to occur. In addition, we tested if it was possible to detect complement-mediated enhancement of primary HIV isolates in PBMC. We tested 3 isolates and found only a minor effect on antigen production (median enhancement 1.2-fold, range 0.6-1.5). Furthermore, addition of HIV-specific antibodies in combination with complement resulted in enhanced antigen production in 2/3 sera tested. However, the combination of complement and antibodies resulted in only a minor increase in enhancement of HIV infection compared to that obtained with complement alone. Finally, we found evidence of complement-mediated enhancement of HIV infection in resting PBMC. In conclusion, we demonstrated that complement-mediated enhancement of HIV infection does occur in vitro in PBMC.

Syncytium-inducing phenotype and zidovudine susceptibility of HIV-1 isolated from post-mortem tissue.

To establish the syncytium-inducing (SI) phenotype and zidovudine (ZDV) susceptibility of HIV-1 isolates obtained from autopsy specimens. Isolation of HIV was attempted from autopsy specimens obtained from 76 AIDS patients. Specimens of lymph node, spleen, spinal cord, brain and cerebrospinal fluid (CSF) were processed and cultured with peripheral blood mononuclear cells (PBMC) from seronegative donors. Biological phenotype was determined in a T-lymphocyte line (MT-2). ZDV susceptibility was evaluated in a PBMC-based assay. Sequencing of amino-acid codons in the reverse transcriptase gene previously shown to be associated with ZDV resistance was carried out on a subgroup of isolates. HIV was recovered from tissue specimens and CSF up to 5 days post-mortem, but recovery rate of infectious virus decreased as the time between autopsy and specimen processing increased. There was a lack of concordance between PBMC isolates and isolates from different tissue sites with respect to SI phenotype. ZDV-resistant virus was isolated from post-mortem specimens of patients who had received long-term ZDV therapy up until or shortly before their death. ZDV-sensitive virus re-emerged in the lymph node of patients who ceased treatment several months prior to death. Phenotypically sensitive virus obtained from lymph node tissue of three patients after a relatively short time off ZDV (4-6 months) retained some of the amino-acid substitutions known to be associated with resistance. The data suggests that ZDV resistance and re-emergence of sensitive virus does not originate in peripheral cells, and that these cells and tissues are seeded with virus present elsewhere, possibly in the germinal centres of the lymph node.

Comparison of viral burden and phenotype of HIV-1 isolates from lymph nodes and blood.

To compare the viral burden and the biological phenotype of HIV-1 isolates obtained from lymphoid node mononuclear cells (LNMC) and peripheral blood mononuclear cells (PBMC) in 11 HIV-infected patients. Viral burden was quantified by cocultivating LNMC and PBMC from HIV-infected patients with PBMC from seronegative donors. For each patient, LNMC and PBMC isolates were characterized in terms of susceptibility to neutralizing antibodies, syncytium-inducing capacity and sensitivity to zidovudine. Our data show that: (1) viral burden was 1.73 log higher in LNMC than PBMC in patients with persistent generalized lymphadenopathy and only 0.37 log higher in patients with AIDS-related complex; (2) five out of 11 LNMC bulk isolates were phenotypically distinct from autologous PBMC isolates; (3) in three patients, the autologous serum neutralized the PBMC isolates but not the LNMC isolates. These results suggest that the relatively high level of HIV-1 replication in lymph nodes may favour the emergence of viruses exhibiting specific phenotypes, including neutralization escape variants. The existence of viral variants in lymphoid tissue at all stages of HIV infection may elucidate certain aspects of the pathogenesis of HIV-1 infection.