Biomedical subjects

D L Rudolph

Publications and source records attributed to D L Rudolph.

At least 19 recordsLinked to original sources

PubMed2006

Field test of a cross-injection scheme for stimulating in situ denitrification near a municipal water supply well.

A pilot-scale test of an in situ denitrification scheme was undertaken to assess an adaptation of the nutrient injection wall (NIW) technology for treating a deep (30-40 m) nitrate contamination problem (N-NO(-)(3) ~ 10-12 mg/L). The adaptation is called the Cross-Injection Scheme (CIS). It duplicates the NIW method without a wall; wells are installed and operated directly in the aquifer and high-flux zones of the aquifer are preferentially targeted for treatment. The test was conducted on the site of a municipal water supply well field, with the supply well pumping between 15-80 m(3)/h. Acetate was periodically injected into the aquifer between an injection-extraction well pair positioned across the normal direction of flow. The injected pulses were then permitted to move with the water toward the municipal wells, providing a carbon supply to drive the desired denitrification. The fate of nitrate, nitrite, acetate and sulphate were monitored at multilevel wells located between the injection location and the municipal wells. The acetate pulsing interval was approximately weekly (9 h injections), so that the system was operating passively 95% of the time. Previous work on the site has established that the highest solute fluxes were associated with a 1-3 m thick zone about 35 m below surface. This zone was found to respond to the acetate additions as a function of the municipal pumping rate and the carbon-to-nitrogen ratio (i.e., determined by the injected acetate concentration). Initially, acetate was injected just below the theoretical stoichiometric requirement for complete denitrification and nitrate disappearance was accompanied by nitrite production. Increasing the C:N ratio (doubling the acetate injection concentration) increased the removal of nitrate and diminished the occurrence of nitrite. Slowing the municipal pumping rate, with a C:N ratio of 1.2-1.6, resulted in complete nitrate attenuation with no nitrite production and no sulfate reduction. The experiment demonstrated that the CIS injection scheme is a viable option for the treatment of nitrate contamination in situ near high-capacity wells.

Acetates↗

PubMed2005

Combined use of field and laboratory testing to predict preferred flow paths in an heterogeneous aquifer.

Elevated nitrate concentrations within a municipal water supply aquifer led to pilot testing of a field-scale, in situ denitrification technology based on carbon substrate injections. In advance of the pilot test, detailed characterization of the site was undertaken. The aquifer consisted of complex, discontinuous and interstratified silt, sand and gravel units, similar to other well studied aquifers of glaciofluvial origin, 15-40 m deep. Laboratory and field tests, including a conservative tracer test, a pumping test, a borehole flowmeter test, grain-size analysis of drill cuttings and core material, and permeameter testing performed on core samples, were performed on the most productive depth range (27-40 m), and the results were compared. The velocity profiles derived from the tracer tests served as the basis for comparison with other methods. The spatial variation in K, based on grain-size analysis, using the Hazen method, were poorly correlated with the breakthrough data. Trends in relative hydraulic conductivity (K/K(avg)) from permeameter testing compared somewhat better. However, the trends in transient drawdown with depth, measured in multilevel sampling points, corresponded particularly well with those of solute mass flux. Estimates of absolute K, based on standard pumping test analysis of the multilevel drawdown data, were inversely correlated with the tracer test data. The inverse nature of the correlation was attributed to assumptions in the transient drawdown packages that were inconsistent with the variable diffusivities encountered at the scale of the measurements. Collectively, the data showed that despite a relatively low variability in K within the aquifer under study (within a factor of 3), water and solute mass fluxes were concentrated in discrete intervals that could be targeted for later bioremediation.

Cities↗

PubMed2001

Self-efficacy, state anxiety, and cortisol responses to treadmill running.

Social cognitive theory of Bandura hypothesizes that increases in self-efficacy act as a mechanism for anxiety reduction and lower biological stress reactions. Therefore, the purpose of the current study was to examine self-efficacy, anxiety, and cortisol responses to 20 minutes of treadmill running at 85% maximal heart rate and a control condition among 12 physically active males. For this study, self-efficacy, anxiety, and cortisol were measured prior to and 5 and 20 min. after exercise for individuals completing a 20-min. treadmill running activity or a 20 min. rest (control) activity. Repeated-measures analyses of variance showed significant condition by time interaction for self-efficacy and cortisol (ps <.05); the exercise group's self-efficacy and cortisol increased pre- to posttreatment. Moreover, the analysis of variance for anxiety yielded a main effect for time, with reductions in anxiety scores observed in both conditions. Correlational analyses showed that posttreatment cortisol levels were inversely correlated -.51 to self-efficacy scores and positively correlated .55 to anxiety scores. The correlation between self-efficacy and anxiety was not significant. These results provide partial support for the predicted relationships among self-efficacy, anxiety, and cortisol responses to treadmill running. Suggestions for research are provided.

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↗

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↗

PubMed1998

Analysis of a biallelic polymorphism in the tumor necrosis factor alpha promoter and HIV type 1 disease progression.

The relevance of a TNF-alpha promoter polymorphism, a G-to-A polymorphic sequence at position-308, was examined to test whether variant alleles of TNF-alpha affect susceptibility to infection with HIV-1 and progression to AIDS. Analysis of specimens from cohorts of HIV-1 positive homosexual men demonstrated that 3 of the 32 (9.4%) HIV-1-infected long-term nonprogressors (LTNPs) were homozygous for the uncommon TNF-2 allele compared with 3 of the 196 (1.5%) HIV-1-seronegative blood donors and uninfected homosexual men (p < 0.05). There was no difference in heterozygosity among HIV-1-seropositive or -seronegative groups, although some of the seropositive men heterozygous for the TNF2 genotype were also heterozygous for CCR5delta32. However, no significant association was found between TNF genotypes and time of survival, CD4 slopes, or viral loads when seroincident (n = 109) and seroprevalent cases (n = 442) from the Chicago MACS were analyzed. Functional analysis of lymphocytes from the seronegative group revealed no difference in endogenous or mitogen-induced TNF-alpha production, as well as susceptibility to in vitro HIV-1 infection between different TNF-genotype donors. These data suggest that TNF genotypes do not play a direct role in HIV-1 disease progression; however, they could potentially be part of a multigenic linkage that may be involved in delaying progression to AIDS.

Acquired Immunodeficiency Syndrome↗

PubMed1998

Influence of positive life events on blood pressure in adolescents.

It has been reported that adults suffering from refractory essential hypertension experience significantly fewer positive life events than healthy peers. However, the influence of positive life events on blood pressure (BP) in adolescents has been largely ignored. Therefore, we examined the relationship between self-reported positive life events and BP in 69 sixth graders with a mean age of 11.7 years. Positive life events were assessed with the Adolescent Perceived Events Scale and resting blood pressure was measured with a mercurial sphygmomanometer. Correlational analyses showed an inverse relationship between positive life events and diastolic BP, suggesting that adolescents experiencing more positive life events were more likely to have lower diastolic BP's. Hierarchical regression analyses revealed that physical activity level, dietary sodium-to-potassium ratio, parental history of hypertension, and measures of body composition predicted 24.6% of the variance in systolic BP and 34.6% of the variance in diastolic BP. Moreover, positive life events predicted an additional 4.3% of the variance in diastolic BP when statistically controlling these established risk factors for hypertension. These results suggest that increased perceptions of positive life events may act as a buffer to elevated BP in adolescents.

Adolescent↗

PubMed1998

Cortisol and affective responses to exercise.

It has been reported that physically active individuals demonstrate attenuated cortisol responses to acute exercise compared to inactive individuals. Furthermore, a number of studies have demonstrated that increased cortisol levels are associated with negative affective states. Conversely, low cortisol levels have been demonstrated to be related to positive psychological constructs such as self-efficacy. However, the roles of activity history and adrenocortical activity in affective responses to acute exercise have not been examined. We therefore compared salivary cortisol, perceived exertion and affective responses to acute exercise in 13 male cross-country runners and 13 non-runners. The experimental trial consisted of a 30 min treadmill run at 60% VO2 max. Cortisol and affective responses were assessed before, during and after exercise; ratings of perceived exertion (RPEs) were recorded during exercise. Analyses of variance indicated no significant group differences in cortisol responses. However, there was a main effect for time (P< 0.05), with cortisol increasing from baseline to the 29th minute of exercise and then decreasing to 30 min post-exercise. Non-runners possessed greater perceptions of effort and negative affect during exercise compared to cross-country runners. Furthermore, the RPEs were positively related to post-exercise cortisol levels (P< 0.05), and affect and cortisol responses were inversely related 30 min post-exercise (P< 0.05). These results provide partial support for the hypothesis that cortisol levels are related to exercise-induced affective states.

Adult↗

PubMed1998

Plasmodium falciparum antigen-induced human immunodeficiency virus type 1 replication is mediated through induction of tumor necrosis factor-alpha.

Because malaria-stimulated cytokine production may have deleterious effects on human immunodeficiency virus type 1 (HIV-1) replication, the effects of Plasmodium falciparum antigens on HIV-1 replication were studied. Stimulation with malarial antigens significantly enhanced HIV-1 replication of HIV-1LAV and primary HIV-1 isolates (subtype A) in CD8-depleted peripheral blood mononuclear cells from naive donors. The malarial antigen-induced activation of HIV-1 was due to cellular activation as judged by the expression of cell activation markers and proliferative responses. While malarial antigen stimulation increased expression of tumor necrosis factor (TNF-alpha) and interleukin-6 (IL-6), only monoclonal antibodies (MAbs) to TNF-alpha inhibited malarial antigen-induced HIV-1 replication, whereas MAb to IL-6 had no effect. Malarial antigen increased HIV-1 replication by increasing viral mRNA expression and by activating long terminal repeat-directed viral transcription. These data suggest that P. falciparum infection can modulate HIV-1 pathogenesis by activating lymphocytes and stimulating viral replication through the production of cytokines.

Animals↗

PubMed1998

Down-regulation of interleukin-10 expression and production is associated with spontaneous proliferation by lymphocytes from human T lymphotropic virus type II-infected persons.

Cytokines from peripheral blood mononuclear cells (PBMC) from human T lymphotropic virus (HTLV)-II-infected persons were studied to delineate the mechanism(s) of spontaneous lymphocyte proliferation (SLP). Culturing HTLV-II-infected PBMC that spontaneously proliferate (SLP+) resulted in greater mRNA expression and production of interferon-gamma, interleukin (IL)-4, and IL-5, with a concomitant decrease in IL-10, than was seen with nonproliferating (SLP ) and normal PBMC. While IL-2 mRNA expression was higher, production was lower in SLP+ PBMC than in SLP and normal PBMC, implying that the proliferating cells are utilizing IL-2. Neutralization of IL-2 resulted in partial inhibition, suggesting that other cytokines also affect SLP. Addition of recombinant IL-10 inhibited the proliferation of SLP+ PBMC. Further, blocking costimulatory signals with monoclonal antibodies against CD80/CD86 resulted in increased IL-10 production with concomitant inhibition of SLP. The mechanism(s) underlying HTLV-II-associated SLP in vitro involve increased utilization of IL-2 and down-regulation of IL-10.

Antigens, CD↗

PubMed1997

Transcriptional activation of the intercellular adhesion molecule 1 (CD54) gene by human T lymphotropic virus types I and II Tax is mediated through a palindromic response element.

In vitro infection of T cells with human T lymphotropic virus types I and II (HTLV-I and HTLV-II) resulted in constitutive expression of ICAM-1. Higher levels of ICAM-1 mRNA were expressed in HTLV-transformed cell lines (MT-2, MoT, C8166) when compared with uninfected T cell lines (A301). We demonstrate that this activation is conferred through a site on the ICAM-1 promoter that is activated in trans by the Tax protein of HTLV-I and HTLV-II. Enhanced promoter activity was detected when the ICAM-1 construct (-1162/+1) was transfected into HTLV-I-infected (MT-2), HTLV-II-infected (MoT, AI 1050), or an HTLV-I Tax-only-expressing (C8166) cell line as compared to the uninfected T cell line (A3.01). Cotransfection of the uninfected T cell line A3.01 with the ICAM construct along with Tax-I and Tax-II expression plasmid also resulted in increased promoter activity. Furthermore, experiments with deletion constructs of the ICAM-1 promoter region indicated that a region between -88 and -53 bp relative to the transcription start site is sufficient for Tax-inducible CAT expression. This segment includes an 11-bp palindromic segment (TTTCCGGGAAA) that has homology with the IFN-gamma and IL-6 response element. An 11-bp segment containing this regulatory region proved to be sufficient to confer Tax-I and Tax-II inducibility on a heterologous promoter (TK-CAT). Taken together these findings indicate that constitutive expression of ICAM-1 by HTLV-infected cells is influenced by the viral trans-activator protein Tax. This increased expression of ICAM-1 in response to the Tax protein may play an important role in the lymphoproliferation associated with HTLV infection.

Cell Line↗

PubMed1997

Low prevalence of HTLV-II in Mayan Indians in the Yucatan Peninsula, Mexico.

Infection with HTLV-II is endemic in Amerindians, with prevalence ranging from 0.89% - 33%. To determine the prevalence of HTLV-II among indigenous Mayans in the Yucatan Peninsula of Mexico, 440 indigenous Mayans were recruited, all native to and residents of one of six Mayan communities in the Yucatan Peninsula, (Xohuayan n=144, Yaxachen n=101, Kanxoc n=84, Xocen n=40, Nabalan n=46 and X'calot n=25) between May, 1992 and June, 1993. All of the above are pre-Hispanic settlements located in tropical forest with no immigrations for over 50 years. Of the 440 indigenous Mayans, only one woman from the X'calot tribe (0.23%) was shown to be infected with HTLV-II. A high percentage of indeterminate results was found (22/439, 5%), three of which were accounted for by the husband and two children of the positive female case. PCR analysis followed by specific restriction digestion demonstrated the virus to be of the HTLV-IIb subtype, similar to that described in the Guaymi Indians from Panama. The presence of HTLV-II in the Mayan ethnos, and in other Amerindian populations supports the idea that HTLV-II is an ancestral virus in America and that it has been sustained in "closed" communities.

Adolescent↗

PubMed1996

Costimulatory effects of T cell proliferation during infection with human T lymphotropic virus types I and II are mediated through CD80 and CD86 ligands.

The modulation of expression of CD80 and CD86 on T cells following infection with human T lymphotropic virus (HTLV)-I/II and its functional importance in T-T cell interactions was examined. Infection with HTLV-I/II leads to constitutive expression of CD80 and CD86, concomitant to down-modulation of CD28 on T cells. The CD80/CD86+ HTLV-infected T cells stimulated proliferation of allogeneic and autologous resting T cells, which could be specifically blocked by a soluble CTLA-4Ig chimeric protein, anti-CD80 or anti-CD86, but not by anti-CD54. It was necessary to inhibit interaction with both ligands (CD80 and CD86) to optimally block HTLV-mediated proliferation of allogeneic and autologous resting T cells. Simultaneous addition of anti-CD8O and anti-CD86 Abs also inhibited production of IFN-gamma, TNF-alpha, and IL-4, with no effect on IL-10 production, for both allo- and autologous T cell proliferation. Further, there was a direct correlation between the spontaneous proliferation of lymphocytes from patients infected with HTLV-II and expression of CD80, which could be blocked by simultaneous addition of anti-CD80 and anti-CD86. Taken together, these results suggest that HTLV-infected CD80/CD86+ T cells serve as APCs, leading to a sustained proliferation of T cells, and that both ligands participate in allostimulation, autologous proliferation, as well as spontaneous proliferation of HTLV-II-infected PBMC.

Adult↗

PubMed1995

In vivo cellular tropism of human T-lymphotropic virus type II is not restricted to CD8+ cells.

We have examined the in vivo and in vitro susceptibility of lymphocyte subpopulations to human T-lymphotropic virus type II (HTLV-II) to determine the cellular tropism for this virus. Monoclonal antibodies to T-cell subsets were used to separate highly purified CD4+ and CD8+ cells from peripheral blood lymphocytes of 35 individuals previously shown to be infected with HTLV-II. The purified T-cell subsets were analyzed for HTLV-II provirus (pol and tax gene sequences) by polymerase chain reaction (PCR) and cultured to determine virus expression by p24gag antigen detection. On the basis of PCR amplification in the pol and tax gene regions, both CD8+ subsets (89 to 91%) and CD4+ subsets (54 to 80%) from most infected subjects demonstrated HTLV-II provirus, irrespective of the viral genotype. Analysis of cultured lymphocytes demonstrated a higher spontaneous lymphocyte proliferation (17,986 +/- 4675 cpm) and p24gag antigen production (median 115 pg/ml; range 14-1360 pg/ml) in CD8+ cells compared to CD4+ cells (2333 +/- 826 cpm; p24gag antigen; 9 pg/ml; 2-250 pg/ml), suggesting a higher proviral load in CD8 cells. Limiting cell-dilution PCR analysis indicated that the CD8+ subset carried a higher HTLV-II provirus burden than the CD4+ subset. In vitro infection of purified CD4+ and CD8+ lymphocytes with irradiated HTLV-II cell lines resulted in productive infection of both subsets. Cell sorting and PCR analysis of lymphocyte subsets from 4 HTLV-II-infected subjects further demonstrated that in addition to CD4+ and CD8+ subsets, both CD45RO+ and CD45RO- and non-T-cells (CD14, CD16, and CD19) carried HTLV-II provirus. Taken together, these data suggest that HTLV-II possesses a broad tropism for peripheral blood mononuclear cells.

Antibodies, Monoclonal↗

PubMed1995

Physique anxiety and exercise in middle-aged adults.

The present study examined the relationships among body composition, exercise participation, and physique anxiety in a sample of middle-aged, formerly sedentary males and females. Study variables were assessed prior to and following participation in a 20-week aerobic exercise program. Subjects reduced their weight, body fat, and body circumferences over the course of the program, as well as physique anxiety. Multivariate and hierarchical regression analyses revealed females and those subjects between 45 and 54 years to be significantly more physique-anxious than their older counterparts. Being female and failing to reduce hip circumference were significantly related to postprogram physique anxiety. Although those who exercised more frequently tended to be less physique-anxious in correlational analyses, exercise frequency was a nonsignificant predictor when controlling for body composition. Thus, it appears that body image is a concern across the female age spectrum rather than the sole province of undergraduate females.

Anthropometry↗

PubMed1995

Infection with human T-lymphotropic virus types I and II results in alterations of cellular receptors, including the up-modulation of T-cell counterreceptors CD40, CD54, and CD80 (B7-1).

To examine the phenotypic alterations associated with human T-lymphotropic virus types I and II (HTLV-I and -II) infection, long-term cell lines (n = 12 HTLV-I cell lines; n = 11 HTLV-II cell lines; n = 6 virus-negative cell lines) were analyzed for the cell surface expression of various lineage markers (i.e., myeloid, progenitor, and leukocyte), integrin receptors, and receptor-counterreceptor (R-CR) pairs responsible for cellular activation. As expected, all cell lines expressed the markers characterizing the leukocyte lineage (CD43, CD44, and CD53). Of the progenitor-myeloid markers examined (CD9, CD13, CD33, CD34, and CD63), only the percent expression of CD9 was significantly increased on HTLV-I and -II-infected cell lines as compared with that on virus-negative cell lines. Analysis of the beta 1 integrin subfamily (CD29, CD49b, CD49d, CD49e, and CD49f) showed no significant change, except that CD49e was significantly decreased on the HTLV-infected cell lines. For the beta 2 integrin subfamily, the cell surface density was increased for CD18 and CD11a, while the CD11c molecule was expressed exclusively on the HTLV-I- and HTLV-II-infected cell lines. Analysis of several R-CR pairs (CD2-CD58, CD45RO-CD22, CD5-CD72, CD11a-CD54, gp39-CD40, and CD28-CD80) demonstrated that comparable levels of expression of the Rs (CD2, CD45RO, CD5, and CD28) and of some of the CRs (CD58, CD22, and CD72) were in all cell lines; however, CD54, CD40, and CD80 were expressed constitutively on the HTLV-I- and HTLV-II-infected cell lines. Functionally, the expression of these R-CR pairs did not appear to affect the autologous proliferation since monoclonal antibodies to these R-CR pairs were not able to inhibit proliferation of the infected cell lines. Taken together, our results indicate that HTLV-I and -II can modulate the expression of several T-cell activation molecules and CRs normally expressed on alternate cell types.

Antigens, CD↗

PubMed1995

Enhanced specificity of truncated transmembrane protein for serologic confirmation of human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2 infections by western blot (immunoblot) assay containing recombinant envelope glycoproteins.

Immunoassays based on the highly immunogenic transmembrane protein of human T-cell lymphotropic virus type 1 (HTLV-1) (protein 21c) are capable of detecting antibodies in all individuals infected with HTLV-1 and HTLV-2. However, because of antigenic mimicry with other cellular and viral proteins, such assays also have a large proportion of false-positive reactions. We have recently identified an immunodominant epitope, designated GD21-I located within amino acids 361 to 404 of the transmembrane protein, that appears to eliminate such false positivity. This recombinant GD21-I protein was used in conjunction with additional recombinant HTLV type-specific proteins and a whole virus lysate to develop a modified Western blot (immunoblot) assay (HTLV WB 2.4). The sensitivity and specificity of this assay were evaluated with 352 specimens whose infection status was determined by PCR assay for the presence or absence of HTLV-1/2 proviral sequences. All HTLV-1-positive (n = 102) and HTLV-2-positive (n = 107) specimens reacted with GD21-1 in the HTLV WB 2.4 assay, yielding a test sensitivity of 100%. Furthermore, all specimens derived from individuals infected with different viral subtypes of HTLV-1 (Cosmopolitan, Japanese, and Melanesian) and HTLV-2 (IIa0, a3, a4, IIb1, b4, and b5) reacted with GD21-I in the HTLV WB 2.4 assay. More importantly, HTLV WB 2.4 analysis of 81 PCR-negative specimens, all of which reacted to recombinant protein 21e in the presence or absence of p24 and p19 reactivity in the standard WB assay, showed that only two specimens retained reactivity to GD21-I, yielding an improved test specificity for the transmembrane protein of 97.5%. None of 41 specimens with gag reactivity only or 21 HTLV-negative specimens demonstrated reactivity to GD21-I. In an analysis of additional specimens (n = 169) from different geographic areas for which PCR results were not available, a substantial increase in the specificity of GD21-I detection was demonstrated, with no effect on the sensitivity of GD21-I detection among specimens from seropositive donors. Thus, the highly sensitive, GD21-I-based HTLV WB 2.4 assay eliminates the majority of false-positive transmembrane results, thereby increasing the specificity for serologic confirmation of HTLV-1 and HTLV-2 infections.

Amino Acid Sequence↗

PubMed1995

Association between maternal antibodies to the external envelope glycoprotein and vertical transmission of human T-lymphotropic virus type I. Maternal anti-env antibodies correlate with protection in non-breast-fed children.

Vertical transmission of human T-lymphotropic virus type I (HTLV-I) depends primarily on breast-feeding; substitution of bottle-feeding has reduced the transmission rate from 20% in breast-fed children to 3% among bottle-fed. To determine the correlates of transmission for long breast-feeding (> or = 6 mo), short breast-feeding (< 6 mo), and bottle-feeding mothers, the antibody titers of transmitter (T) mothers and non-transmitter (nT) mothers were analyzed by using synthetic and recombinant epitopes representing the immunodominant epitopes of gag (Gag1a, r24), env (Env1/5, MTA1, RE3), and tax (Tax8/22-24) proteins. Seroreactivity to gag and tax epitopes was not significantly different except for anti-r24 antibody titer, which was significantly higher among T-mothers (geometric mean 134) when compared with nT-mothers (62) in the long-feeding group (P < 0.001). Profiles of antibody titers against env epitopes were different. Within the long-feeding group, Env1/5, MTA1, and RE3 titers were significantly higher among T-mothers (258, 1,476, and 738, respectively) when compared with nT-mothers (106, 279, and 320, respectively) (P < 0.01 for all three epitopes). In contrast, within the bottle-feeding group, antibody titers to Env1/5 (269) and RE3 (418) among nT-mothers were significantly higher than those among T-mothers (80 and 113, respectively) (P < 0.01). These data confirm that high-titered anti-HTLV-I antibodies in the long-feeding group correlate with milk-borne transmission of HTLV-I and, more importantly, imply that maternal anti-env antibodies may reduce the risk of non-milkborne infection.

Amino Acid Sequence↗