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Detection and differentiation of HIV-1 group O sera from HIV-1 group M and HIV-2 using recombinant antigens and peptides.

Recombinant antigens and peptides were used to develop an HIV slot immunoblot assay to confirm and differentiate infection by HIV-1 group M, HIV-1 group O or HIV-2. Recombinant antigens from the gag, pol or env regions of HIV-1 and HIV-2, in addition to synthetic peptides from the immunodominant region (IDR) of transmembrane proteins gp41 (HIV-1) or gp36 (HIV-2), were blotted on nitrocellulose strips and used as a substitute for competitive Western blots. Evaluation of a large number of samples (N = 440) from various regions of the world, using the immunoblot, showed effective differentiation of HIV-1 group M, HIV-1 group O and HIV-2. The immunoblot identified correctly all (24/24) HIV-1 group O samples that were confirmed subsequently by PCR and sequence analysis. The immunoblot is a useful tool for identifying HIV-1 group O seropositive samples and has the potential to identify other serological HIV variants that may represent detection problems for HIV screening assays using HIV-1 group M subtype B reagents.

Amino Acid Sequence↗

Unexpected non-HIV causes of death in children born to HIV-infected mothers. Pediatric Pulmonary and Cardiac Complications of Vertically Transmitted HIV Infection Study Group.

INTRODUCTION: A high incidence of sudden, unexplained deaths in infants born to HIV-infected mothers has been noted in several epidemiologic studies. During the course of a prospective study of heart and lung disease in children born to HIV-infected mothers, we noted that of 5 unexpected non-HIV-related deaths, 4 were attributed to traumatic events. METHODS: The Pediatric Pulmonary and Cardiac Complications of Vertically Transmitted HIV Infection (P2C2) study is a multicenter, prospective investigation of the incidence of heart and lung disease in HIV-infected children. A total of 805 children were enrolled and followed for 5 to 7 years with serial immunologic, pulmonary and cardiac function studies. During the study, a multidisciplinary committee was formed to review the cause of death for those patients who died. The committee used results of pulmonary, cardiac, and laboratory tests, hospital summaries, as well as autopsy and coroners' reports. The committee formed a consensus about the underlying and contributing causes of death for each subject using the definitions from the 1989 US Standard Certificate of Death. RESULTS: A total of 121 deaths occurred during the course of the P2C2 study. Of the 121 deaths, 5 were traumatic or sudden and unexpected and judged by the Mortality Review Committee to be unrelated to HIV infection. The median age at the time of death was 1.3 months and ranged from 1.2 to 37.8 months. Two infants died of trauma: a skull fracture and subdural hematoma in 1 infant and multiple skeletal fractures consistent with battered child syndrome in the other infant. The third infant died of accidental suffocation at home at 1.2 months of age. The fourth infant died suddenly and unexpectedly at home at 1.3 months of age. The autopsy showed no sign of HIV or other infection and was consistent with sudden unexpected death or SIDS. One non-HIV-related death occurred when a 38-month-old child died together with the mother in an unwitnessed drowning. The cumulative mortality rate attributable to trauma and sudden death at 4 months of age was 0.95% (95% CI: 0.02-1. 87%) and the infant mortality rate was 9.5/1000 live births. Three children were born prematurely at 30, 33, and 36 weeks' gestational age, respectively, and 3 mothers admitted using recreational drugs before or during pregnancy. DISCUSSION: These traumatic and sudden non-HIV-related deaths accounted for 4.1% (5/121) of the deaths during the entire P2C2 study period and for 20% (4/20) of the deaths in the first year of life. Four deaths were attributable to accidental and nonaccidental trauma rather than to other common causes of infant death. One death was a sudden unexpected death, similar to SIDS, a leading cause of infant death in the United States. The majority of previously reported non-HIV-related deaths in infants born to HIV-infected mothers have been attributed to SIDS or to unexplained sudden death. In contrast with other reports, 4 of the 5 children in our series died of accidental or nonaccidental trauma and only 1 was a sudden unexplained death. It is unlikely that HIV exposure is related directly to the deaths described in this report; however, maternal HIV infection may be a marker for factors that place the child at risk for sudden or traumatic death. SUMMARY: This report suggests that children born to HIV-infected mothers may be at increased risk for traumatic or sudden, unexplained, non-HIV-related death. These children seem to be at risk regardless of their own HIV infection status. Furthermore, 4 of the deaths in our study occurred within the first few months of life, suggesting that this is a period of increased vulnerability. Studies to identify associated risk factors for non-HIV-related deaths are needed to identify these high-risk infants. Children born to HIV-infected mothers may be more vulnerable than was recognized previously and may be in need of increased social services, especially in early infancy.

Cause of Death↗

HIV-induced, HIV-specific in vitro antibody response by B-cells from HIV-seropositive individuals.

OBJECTIVE: Recent studies have shown that B-cells from HIV-infected patients can secrete anti-HIV antibodies in vitro and that they represent 20-40% of immunoglobulin (Ig)-secreting B-cells in vivo. This study was designed to investigate the precise role of HIV in this in vitro antibody production. DESIGN AND METHODS: B-cells from HIV-infected patients [asymptomatic, n = 28; symptomatic (AIDS), n = 14], from seronegative adult volunteers (n = 22) and subjects at high risk for HIV infection (n = 15) were cultured in vitro in the presence of pokeweed mitogen, Staphylococcus aureus cowan or HIV, and T-cells or interleukins (IL). Non-specific Ig production and specific anti-HIV antibody (Ab) production were measured by enzyme-linked immunosorbent and Western blot assays. RESULTS: We found that HIV induced a specific response in cultured B-cells from seropositive patients, in contrast with cultured B-cells from uninfected normal individuals. The characteristics of the HIV-induced response differed from those of a spontaneous or a mitogen-induced response. Anti-HIV Ab production was optimal on day 8-10, when B-cells were cultured with recombinant IL-2 and recombinant interferon-alpha in the presence of infectious virus or recombinant gp160 Env protein. The anti-HIV Ab were mainly directed against Env proteins. Interaction of HIV with B-cells involved surface IgG but not CD4 antigen. Autologous CD8+ T-cells had a non-specific inhibitory effect. Both CD5+ and CD5- B-cells produced anti-HIV Ab. No anti-HIV Ab production was observed in B-cells from high-risk HIV-seronegative individuals. CONCLUSION: HIV (infectious virus or gp160) can induce B-cells from infected patients to secrete specific anti-HIV Ab in vitro.

Adult↗

HIV-1 and HIV-2 dual infection: lack of HIV-2 provirus correlates with low CD4+ lymphocyte counts.

OBJECTIVE: We conducted this study to genetically characterize dual infection in individuals demonstrating a dual serological profile. METHODS: All subjects were first evaluated by immunoblot for antibody reactivity to the major viral antigens for HIV-1 and HIV-2. Sera were judged to be dual-seropositive if they reacted with strong and equal intensity with the envelope antigens of both HIV-1 and HIV-2 and were confirmed with type-specific recombinant env peptides. We used nested polymerase chain reaction (PCR) to amplify proviral gag and env sequence from peripheral blood mononuclear cell (PBMC) DNA from HIV-1- and HIV-2-infected individuals. Positive amplification was detected after Southern blot hybridization. RESULTS: Plasmid dilution and mixing showed equivalent sensitivity of HIV-1 and HIV-2 primers that was not altered by heterologous target sequences. The DNA PCR showed 100% sensitivity and specificity for detection of monotypic HIV infection. Serologically defined HIV-dual reactives were evaluated by this assay, with 100% detection in female sex workers (21 out of 21), but only 38.5% detection (five out of 13) in hospitalized patients; all being HIV-1 positive only. The lack of HIV-2 proviral signal was significantly correlated with low CD4+ lymphocyte counts (Pvalue = 0.04). CONCLUSION: The results suggest that HIV dual infection may not be a static condition. Levels of HIV-2 may decrease with disease progression or sequester in tissue reservoirs; our results may also suggest that HIV-1 effectively overgrows HIV-2 in the dually exposed host individual.

Blotting, Southern↗

A neuronal and neuroanatomical correlate of HIV-1 encephalopathy relative to HIV-1 encephalitis in HIV-1-infected children.

Progressive central nervous system dysfunction analogous to the AIDS dementia complex (ADC) seen in adults (HIV-1-associated progressive encephalopathy or HIV-1 encephalopathy) commonly occurs in HIV-1-infected children. The cause appears to be directly or indirectly related to HIV-1, rather than to other opportunistic pathogens. The exact mechanism(s) by which the virus affects brain function is not known. To determine whether the virus might modify brain function via an alteration in cortical neurons, we examined peptide neurotransmitter expression in the frontal cortex of HIV-1-infected cases with clinical HIV-1 encephalopathy relative to pathologic HIV-1 encephalitis. In situ hybridization was used to determine the level of peptide neurotransmitter expression of somatostatin in the frontal cortex of cases with and without HIV-1 encephalopathy and/or HIV-1 encephalitis. A 2-fold higher number of preprosomatostatin mRNA-positive interneurons was present in layer IV of cases with HIV-1 encephalitis compared with cases without HIV-1 encephalitis. In cases with PE, this neuronal alteration was 4- to 5-fold higher than in cases without PE, and was present in subcortical white matter in addition to layer IV. In cases having both PE and HIV-1 encephalitis, and in cases with HIV-1 encephalitis alone, these neuronal alterations in layer IV and/or subcortical white matter related to disseminated microglial nodules, even when these potentially viral-infected cells were negative for HIV-1 p24 antigen, a marker of productive viral infection. An alteration in preprosomatostatin mRNA-expressing cells occurring with HIV-1 encephalitis may be at least one mechanism that contributes to HIV-1 encephalopathy. When compared with other cortical laminae, layer IV receives most of its synaptic input from the mediodorsal nucleus of the thalamus. Neurons in the subcortical white matter project to the thalamus. The thalamus has been shown to have high amounts of viral antigen and increased metabolic activity in patients with AIDS. An alteration in preprosomatostatin mRNA-expressing cells may play a role in HIV-1 encephalopathy.

AIDS Dementia Complex↗

Comparison of clinical manifestations of HIV infection among women by risk group, CD4+ cell count, and HIV-1 plasma viral load. HER Study Group. HIV Epidemiology Research.

OBJECTIVES: To compare the prevalence of HIV-related symptoms, physical examination findings, and hematologic variables among women whose risk for HIV is injection drug use since 1985 as opposed to sexual contact and to evaluate the influence of HIV plasma viral load and CD4+ cell count on clinical manifestations according to risk. METHODS: Participants of the HIV Epidemiology Research Study (HERS; a multicenter, prospective, controlled study of HIV infection in women) were administered a risk behavior and symptom interview, underwent a physical examination, and received hematologic testing, including CD4+ cell counts done on study entry. Plasma HIV-1 viral loads were performed on stored frozen plasma using an ultrasensitive branched-DNA (b-DNA) signal amplification assay. CD4+ counts were categorized as <200 cells/microl, 200 to 499 cells/microl, or > or =500 cells/microl, and HIV viral loads were characterized in tertiles. RESULTS: Cross-sectional analysis was conducted on data available for 724 HIV-infected women: 387 had a history of intravenous drug use and 337 were infected through heterosexual contact. The median CD4+ count was 376 cells/microl; the median HIV-1 viral load was 1135 copies/ml; and 281 of 724 HIV-infected women (38.8%) had an undetectable HIV-1 viral load. In analyses adjusting for CD4+ cell level alone and for plasma viral load combined with CD4+ cell level, injection drug users (IDUs) were more likely than those infected through heterosexual contact to report a recent episode of memory loss and weight loss, but less likely to have recent episodes of genital herpes; to have enlarged livers and a body mass index (BMI) <24, and to have hematocrit levels <34% and platelet counts <150,000 cells/ml. After adjustment for CD4+ cell level and risk group, high and medium HIV-1 plasma viral load levels were associated with the presence of oral hairy leukoplakia on examination, and only the highest level of plasma viral load was associated with recent histories of fever and thrush, oral hairy leukoplakia, pseudomembranous candidiasis, and BMI <24 on examination, and hematocrit <34%. CONCLUSIONS: In this cohort of women, the distribution of HIV-1 plasma viral load was lower than that previously reported in populations of HIV-infected men. This study also shows some differences in frequency of signs, symptoms, and laboratory values between risk groups of HIV-infected women, but these results may be due to effects of injection drug use rather than HIV infection. Signs and symptoms identified as associated with increasing levels of viral load that were not different across risk groups suggest more direct association of these findings with HIV infection.

Adult↗

Detection of HIV-Gag p24-specific antibodies in sera and saliva of HIV-1-infected adults and in sera of infants born to HIV-1-infected mothers.

Secretory immunoglobulin A (IgA) is known to play an important role in the mucosal defense against a variety of pathogens. Although the role of IgA antibodies during sexual transmission of HIV is not clear, HIV-specific IgA antibodies have been detected in various mucosal secretions of HIV-infected individuals. Using a monoclonal antibody against human IgA, we established an ELISA system to detect anti-HIV p24 IgA antibodies in sera and saliva. We have analyzed the levels of anti-HIV p24 IgG and IgA antibodies in sera and saliva of 107 and 119 adults, respectively, with HIV infection at different clinical stages, and in the sera of 13 infants born to HIV-infected mothers. The level of anti-HIV p24 IgA antibodies was lower in sera and higher in saliva as compared to that of anti-HIV p24 IgG antibodies. Where the percentage of HIV-specific serum antibody-positive cases decreased with disease progression, that of saliva antibody-positive cases increased in AIDS patients. Among the 13 infants born to HIV-infected mothers, 7 infants were HIV-p24-specific serum IgA positive. These sera were negative for anti-HIV p24 secretory IgA, suggesting that some infants develop their own immune responses against HIV infection. Thus, the detection of HIV-specific IgA antibodies, especially in saliva, could be a simple and reliable test for the diagnosis of HIV infection.

AIDS Serodiagnosis↗

Efficacy of HIV PCR techniques to diagnose HIV in infants born to HIV infected mothers--an Indian perspective.

AIM: To determine the efficiency of HIV DNA PCR (qualitative) and HIV RNA PCR (quantitative) to detect or rule out HIV infection in infants born to HIV infected mothers. SETTING: Pediatric and perinatal HIV clinic in a tertiary pediatric hospital. STUDY DESIGN: Prospective study METHODS AND MATERIALS: 52 infants born to HIV positive mother were tested for HIV infection by HIV DNA PCR or HIV-1 viral load from 1.5 to 7 months of age. Their HIV status was confirmed by an HIV ELISA test at 18 months of age. RESULTS: Of the 36 patients tested by HIV DNA PCR test, 15 patients (41.8%) had a positive test and 21 patients (58.2%) had a negative test. 12 patients (80%) had a false positive test (80%) and no patient had a false negative test. Sensitivity of HIV DNA test 100% with specificity of 53.9%. Of the 18 patients tested by HIV viral load, 17 patients (94.4%) had a negative test and 1 patient (5.6%) had a positive test. No patient had a false negative or false positive test. Sensitivity and specificity of HIV viral load was 100%, which was statistically significant (p=0.0004). CONCLUSION: HIV-RNA PCR (quantitative) is highly specific and sensitive test for diagnosing and excluding perinatal HIV infection in children in India.

DNA, Viral↗

The effects of dilution on the outcome of pooled plasma testing with HIV type 1 (HIV-1) RNA genome amplification as compared to the outcome of individual-unit testing with other HIV-1 markers.

BACKGROUND: Proposed testing of large plasma pools with genome amplification technology (GAT) for detection of transfusion-transmissible viruses may have unanticipated complications not associated with individual unit testing. One such potential complication, the effect of dilution resulting from pool formation, was the subject of the present study. STUDY DESIGN AND METHODS: Specimens from three plasma donor HIV type 1 (HIV-1) seroconversion panels were tested with a quantitative HIV-1 RNA GAT assay (lower detection limit, 400 copies). GAT results were compared to HIV-1 p24 antigen and anti-HIV-1/2 enzyme immunoassay results. Effects of dilution on the detection of GAT-positive panel specimens were assessed by terminal dilution with pooled volunteer-donor EDTA plasma samples. RESULTS: Low HIV-1 RNA copy numbers (755 and 890 copies/0.1-mL input) that were detectable in two individual plasma specimens before HIV-1 p24 antigen were subsequently undetectable by GAT upon dilution with an equal volume of nonreactive plasma from a single donor. HIV-1 RNA at higher copy numbers (15,500 copies/0.1-mL input) in an HIV-1 p24 antigen-reactive and anti-HIV-1/2-nonreactive specimen was undetectable when diluted to 1-in-50 (1-in-50). Terminal dilution of seven HIV-1 RNA-containing plasma panel specimens indicated a proportional loss of HIV-1 RNA detectability with increasing dilution. CONCLUSION: GAT for detection of HIV-1 RNA in individual specimens was more sensitive than other HIV markers. For pooled plasma testing, GAT-independent constraints, such as effects of dilution, may preclude the use of GAT detection as a replacement for individual unit testing with HIV serologic assays.

Gene Amplification↗

HIV-1 in placentas of untreated HIV-1-infected women in relation to viral transmission, infectious HIV-1 and RNA load in plasma.

The presence of HIV in the placenta was analysed in relation to virological and immunological factors and vertical transmission of HIV in 39 pregnancies between 1989 and 1993 among 37 HIV-1-infected women without zidovudine prophylaxis. HIV-1 was detected in 12 of 37 (31%) placentas by immunohistochemistry and in 3 of 18 by PCR. Altogether 14/39 (36%) placentas bore evidence of HIV-1 infection, although there was no relation with the outcome of HIV infection in the child. Neither was there a relation between placental infection and either CD4 cell counts or HIV-1 RNA levels. However, HIV-1 was isolated from plasma in 20 of 39 (50%) pregnancies, which was inversely related to the presence of HIV in the placenta. When HIV-1 was identified in the placenta, HIV-1 was isolated from plasma in 3/14 (21%) pregnancies, vs 17/25 (68%) when it was not (p = 0.01), with a relative risk of having a placenta positive for HIV of 3.9 in pregnancies with a negative plasma HIV isolation. This inverse relation may point to differences in tropism between HIV-1 in placenta and plasma. The results show that the placental barrier prevents HIV transmission, irrespective of whether HIV enters the placenta or not.

CD4 Lymphocyte Count↗

Periodontal status of HIV-1 and HIV-2 seropositive and HIV seronegative female commercial sex workers in Senegal.

Comprehensive studies of 92 commercial sex workers in Senegal, Africa included an oral examination in which we obtained measurements of decayed, missing, and filled (DMF) teeth; plaque index; gingival index; recession; probing depth (PD); clinical attachment loss (CAL); and the presence of HIV-associated periodontal lesions, under conditions wherein the examiner was unaware of the subject's HIV status. Twenty-seven subjects (29%) were HIV seropositive, 19 of whom were positive for HIV-1, 7 positive for HIV-2, and 1 positive for both. Most subjects were not taking any medications and previous dental care was limited. HIV-seronegative and HIV-seropositive subjects were similar in mean age, number of DMF teeth, percentage of sites with visible plaque, and number of sites with recession. However, the frequency of sites with gingival bleeding, with PD > or = 6 mm, and with CAL > or = 6 mm was significantly greater in seropositive than seronegative subjects. No differences were observed between HIV-1 and HIV-2 positive subjects. About 26% of HIV-seropositive subjects and about 5% of the seronegative subjects exhibited at least one site with concurrent PD > or = 6 mm and CAL > or = 6 mm. HIV-associated periodontal lesions were seen in 3 HIV-seropositive subjects (2 linear gingival erythema, 1 necrotizing periodontitis). One HIV-seronegative subject exhibited necrotizing gingivitis. In this population with multiple risks to oral health, both HIV-1 and HIV-2 infections were associated with a significantly increased prevalence of periodontal disease.

Adolescent↗

Identification of HIV-1 epitopes that induce the synthesis of a R5 HIV-1 suppression factor by human CD4+ T cells isolated from HIV-1 immunized hu-PBL SCID mice.

We have previously reported that immunization of the severe combined immunodeficiency (SCID) mice reconstituted with human peripheral blood mononuclear cells (PBMC) (hu-PBL-SCID mice) with inactivated human immunodeficiency virus type-1 (HIV-1)-pulsed-autologous dendritic cells (HIV-DC) elicits HIV-1-reactive CD4(+) T cells that produce an as yet to be defined novel soluble factor in vitro with anti-viral properties against CCR5 tropic (R5) HIV-1 infection. These findings led us to perform studies designed to identify the lineage of the cell that synthesizes such a factor in vivo and define the epitopes of HIV-1 protein that have specificity for the induction of such anti-viral factor. Results of our studies show that this property is a function of CD4(+) but not CD8(+) T cells. Human CD4(+) T cells were thus recovered from the HIV-DC-immunized hu-PBL-SCID mice and were re-stimulated in vitro by co-culture for 2 days with autologous adherent PBMC as antigen presenting cells, APC previously pulsed with inactivated HIV in IL-2-containing medium to expand HIV-1-reactive CD4(+) T cells. Aliquots of these re-stimulated CD4(+) T cells were then co-cultured with similar APC's that were previously pulsed with 10 microg/ml of a panel of HIV peptides for an additional 2 days, and their culture supernatants were examined for the production of both the R5 HIV-1 suppression factor and IFN-gamma. The data presented herein show that the HIV-1 primed CD4(+) T cells produced the R5 suppression factor in response to a wide variety of HIV-1 gag, env, pol, nef or vif peptides, depending on the donor of the CD4(+) T cells. Simultaneous production of human interferon (IFN)-gamma was observed in some cases. These results indicate that human CD4(+) T cells in PBMC of HIV-1 naive donors have a wide variety of HIV-1 epitope-specific CD4(+) T cell precursors that are capable of producing the R5 HIV-1 suppression factor upon DC-based vaccination with whole inactivated HIV-1.

Animals↗

Potent antiretroviral treatment of HIV-infection results in suppression of the seminal shedding of HIV. The Swiss HIV Cohort Study.

OBJECTIVE: The amount of HIV in semen likely influences infectiousness. Antiretroviral therapy decreases HIV-RNA in semen, but data on HIV concentrations in semen in a large cohort of men with suppressed HIV-RNA in blood is unavailable. METHODS: Male patients with a treatment-induced reduction of HIV-RNA load in plasma below 400 copies/ml were asked to donate a semen and blood sample. Blood and seminal plasma were tested for the presence of HIV-RNA by the NucliSens method (detection limit 400 copies/ml). Seminal cell samples from 67 patients were further analysed for the presence of HIV-DNA using a nested DNA-polymerase chain reaction. Results of RNA and DNA testing in semen were compared with 55 HIV-positive antiretroviral therapy-naive men. RESULTS: A total of 114 patients participated in the study. Seminal plasma HIV-RNA was detectable in only two patients [1.8%, 95% confidence ratio (CI), 0-4.2%] compared with a detection frequency of 67% in untreated controls [Odds ratio (OR), 0.01; 95% CI, 0-0.03]. Detection of cell-associated HIV-DNA in semen was significantly less frequent (16 versus 38%) in patients receiving suppressive therapy compared with untreated controls (OR, 0.32; 95% CI, 0.12-0.80). CONCLUSION: In patients with treatment-induced suppression of blood viral load the likelihood of having detectable HIV in semen is very low (< 4%). In addition, seminal shedding of cell-free and cell-associated HIV is significantly lower than in an untreated population of HIV-infected asymptomatic men. On a population basis, this effect of therapy may help to reduce sexual transmission of HIV. However, individual patients may still be infected as evidenced by continued shedding of cells harbouring the HIV provirus.

Anti-HIV Agents↗

"Why I am not infected with HIV": implications for long-term HIV risk reduction and HIV vaccine trials.

OBJECTIVE: To describe beliefs about remaining HIV-seronegative in injecting drug users in two high-seroprevalence cities, and to consider implications of these beliefs for ongoing risk reduction efforts and for HIV vaccine efficacy trials. DESIGN: Cross-sectional survey with open- and closed-ended questions. SUBJECTS: 58 HIV-seronegative injecting drug users participating in HIV vaccine preparation cohort studies in New York City, New York, U.S.A., and Bangkok, Thailand. MAJOR FINDINGS: Large majorities of subjects in Bangkok (90%) and in New York (89%) believed their "own efforts" to practice safer injection methods and safer sex were very important in avoiding HIV infection. More Bangkok subjects (30%) believed that they would "probably" become infected with HIV in the future than New York subjects (4%). Three percent of Bangkok subjects and 70% of New York subjects believed "having an immune system strong enough to avoid becoming infected with HIV despite exposure to the virus" was very important in avoiding HIV infection. This belief in New York subjects was associated with having previously engaged in high-risk behaviors (i.e., sharing injection equipment, unprotected sex, or both) with partners known to be HIV-seropositive. CONCLUSIONS: Risk reduction programming for high-HIV-seroprevalence populations and within HIV vaccine trials should address not only specific HIV risk behaviors, but also the complex belief systems about avoiding HIV infection that develop within such groups. The person's "own efforts/self-efficacy" appears to be central in the psychology of risk reduction. Members of some high-risk populations may overestimate greatly the frequency of any possible natural immunity to becoming infected with HIV. Prevention programs for these populations will need to address explicitly the probabilistic nature of HIV transmission.

AIDS Vaccines↗

Discordance between frequency of human immunodeficiency virus type 1 (HIV-1)-specific gamma interferon-producing CD4(+) T cells and HIV-1-specific lymphoproliferation in HIV-1-infected subjects with active viral replication.

One hallmark of uncontrolled, chronic human immunodeficiency virus type 1 (HIV-1) infection is the absence of strong HIV-1-specific, CD4(+) T-cell-proliferative responses, yet the mechanism underlying this T helper (Th)-cell defect remains controversial. To better understand the impact of HIV-1 replication on Th-cell function, we compared the frequency of CD4(+) Th-cell responses based on production of gamma interferon to lymphoproliferative responses directed against HIV-1 proteins in HIV-1-infected subjects with active in vivo viral replication versus those on suppressed highly active antiretroviral therapy (HAART). No statistically significant differences in the frequencies of cytokine-secreting, HIV-1-specific CD4(+) T cells between the donor groups were found, despite differences in viral load and treatment status. However, HIV-1-specific lymphoproliferative responses were significantly greater in the subjects with HAART suppression than in subjects with active viral replication. Similar levels of HIV-1 RNA were measured in T-cell cultures stimulated with HIV-1 antigens regardless of donor in vivo viral loads, but only HIV-1-specific CD4(+) T cells from subjects with HAART suppression proliferated in vitro, suggesting that HIV-1 replication in vitro does not preclude HIV-1-specific lymphoproliferation. This study demonstrates a discordance between the frequency and proliferative capacity of HIV-1-specific CD4(+) T cells in subjects with ongoing in vivo viral replication and suggests that in vivo HIV-1 replication contributes to the observed defect in HIV-1-specific CD4(+) T-cell proliferation.

Adult↗

Cytomegalovirus infection and HIV-1 disease progression in infants born to HIV-1-infected women. Pediatric Pulmonary and Cardiovascular Complications of Vertically Transmitted HIV Infection Study Group.

BACKGROUND AND METHODS: Cytomegalovirus (CMV) has been implicated as a cofactor in the progression of human immunodeficiency virus type 1 (HIV-1) disease. We assessed 440 infants (75 of whom were HIV-1-infected and 365 of whom were not) who had known CMV status and were born to HIV-1-infected women and who were followed prospectively. HIV-1 disease progression was defined as the presence of class C symptoms (according to the criteria of the Centers for Disease Control and Prevention [CDC]) or CD4 counts of less than 750 cells per cubic millimeter by 1 year of age and less than 500 cells per cubic millimeter by 18 months of age. RESULTS: At birth the frequency of CMV infection was similar in the HIV-1-infected and HIV-1-uninfected infants (4.3 percent and 4.5 percent, respectively), but the HIV-1-infected infants had a higher rate of CMV infection at six months of age (39.9 percent vs. 15.3 percent, P=0.001) and continued to have a higher rate of CMV infection through four years of age (P=0.04). By 18 months of age, the infants with both infections had higher rates of HIV-1 disease progression (70.0 percent vs. 30.4 percent, P=0.001), CDC class C symptoms or death (52.5 percent vs. 21.7 percent, P=0.008), and impaired brain growth or progressive motor deficits (35.6 percent vs. 8.7 percent, P=0.005) than infants infected only with HIV-1. In a Cox regression analysis, CMV infection was associated with an increased risk of HIV-1 disease progression (relative risk, 2.59; 95 percent confidence interval, 1.13 to 5.95). Among children infected with HIV-1 alone, but not among those infected with both viruses, children with rapid progression of HIV-1 disease had higher mean levels of HIV-1 RNA than those with slower or no progression of disease. CONCLUSIONS: HIV-1-infected infants who acquire CMV infection in the first 18 months of life have a significantly higher rate of disease progression and central nervous system disease than those infected with HIV-1 alone.

Acquired Immunodeficiency Syndrome↗

Suppression of HIV-1 replication by HIV-1-irrelevant CD8+ cytotoxic T lymphocytes resulting in preservation of persistently HIV-1-infected cells in vitro.

CD8+ cells of asymptomatic HIV-1 carriers (AC) contain HIV-1-specific cytotoxic T lymphocytes (CTLs) but suppress HIV-1 replication in a class I major histocompatibility complex (MHC-I)-unrestricted manner. In order to selectively investigate the HIV-1-suppressive function of CTLs apart from HIV-1-specific cytotoxicity, HIV-1-irrelevant allo-specific CTLs were established from an HIV-1-uninfected individual and their HIV-1-suppressive activity against autologous CD4+ peripheral blood mononuclear cells (PBMC) was examined. We found that these CTLs significantly suppressed both R5 and X4-HIV-1 replication in either acutely or persistently infected autologous PBMC. Although these CTLs partially killed HIV-1-infected PBMC through Fas ligand, CTLs still suppressed late steps of HIV-1 replication in the presence of neutralizing antibodies to Fas ligand. HIV-1 replication in PBMC that had been suppressed by CTLs was reversible following depletion of CTLs from culture, analogous to the previous observation for CD8+ cell-depleted PBMC of AC. Induction of HIV-1 replication by CTL-depletion was amplified by addition of newly prepared CD4+ cells or activation with staphylococcal enterotoxin B. Our results indicate that CTLs can suppress HIV-1 replication in PBMC in an antigen-nonspecific manner and preserve infected cells in a state capable of restarting HIV-1 replication and transmission.

CD4-Positive T-Lymphocytes↗

Inhibition of human immunodeficiency virus-1 (HIV-1) replication after transduction of granulocyte colony-stimulating factor-mobilized CD34+ cells from HIV-1-infected donors using retroviral vectors containing anti-HIV-1 genes.

Transfer of "anti-HIV-1 genes" into hematopoietic stem cells of human immunodeficiency virus-1 (HIV-1)-infected individuals may be a potent therapeutic approach to render mature cells arising from transduced stem cells resistant to the destructive events associated with HIV-1 infection. To determine the feasibility of gene therapy for acquired immunodeficiency syndrome in individuals already infected with HIV-1, granulocyte colony-stimulating factor mobilized peripheral blood CD34+ cells were isolated from HIV-1-infected individuals and transduced with retroviral vectors containing three different anti-HIV-1-genes: the Rev binding domain of the Rev Responsive Element (RRE decoy) (L-RRE-neo), a double hammerhead ribozyme vector targeted to cleave the tat and rev transcripts (L-TR/TAT-neo), and the trans-dominant mutant of rev (M10) (L-M10-SN). As a control, a vector mediating only neomycin resistance (LN) was used. After 3 days of transduction on allogeneic stroma in the presence of stem cell factor, interleukin-6 (IL-6), and IL-3, the cultures were G418-selected, and then challenged with HIV-1(JR-FL) and a primary HIV-1 isolate. Compared with the control cultures, the L-RRE-neo-, L-TR/TAT-neo-, and L-M10-SN-transduced cultures displayed up to 1,000-fold inhibition of HIV-1 replication after challenge with HIV-1(JR-FL) and the primary HIV-1 isolate. Growth of the hematopoietic cells in long-term bone marrow culture was not perturbed by the presence of any of the anti-HIV-1 genes. This study shows that anti-HIV-1 genes can be introduced into CD34+ cells from individuals already infected with HIV-1, and strongly inhibit HIV-1 replication in primary monocytes derived from the CD34+ progenitors.

Binding Sites↗