Gunnel Biberfeld

REPLICATIVE CAPACITY OF HUMAN IMMUNODEFICIENCY VIRUS FROM PATIENTS WITH VARYING SEVERITY OF HIV INFECTION

T-lymphotropic viruses were isolated from 31 patients with different clinical manifestations of human immunodeficiency virus (HIV) infection. Lymphocyte cultures from patients with the acquired immunodeficiency syndrome (AIDS) or pre-AIDS yielded virus rapidly, as indicated by high levels of reverse transcriptase (RT) activity in culture fluids. These viruses were able to establish a persistent infection in several T4-antigen-positive tumour cell-lines. In contrast, lymphocyte cultures from patients with mild or no symptoms yielded virus more slowly and the RT activity was low. Co-cultivation of slow/low-yielding lymphocytes with T4-positive tumour cell-lines showed no or only transient virus production. In 14 out of 23 cases virus could be detected by their fatal cytopathic effects on tumour cells. The relation between severity of illness and in-vitro replication potential of the viruses suggests that in the course of an infection selection may occur for HIV variants that replicate efficiently in T4 cells.

Prevention of mother-to-child transmission of HIV-1 through breastfeeding by treating mothers with triple antiretroviral therapy in Dar es Salaam, Tanzania: the Mitra Plus study.

Objective:The main aim of this study was to reduce breast-milk transmission of HIV-1 by treating HIV-1-infected women with highly active antiretroviral therapy (HAART) during breastfeeding. Methods:Mitra Plus was an open-label, nonrandomized, prospective cohort study. HIV-1-infected pregnant women in Dar es Salaam were treated with zidovudine (ZDV) + lamivudine (3TC) + nevirapine (NVP). NVP was later replaced by nelfinavir for mothers with CD4 cell counts >200 cells per microliter or with adverse reaction to NVP. HAART was initiated at 34 weeks of gestation. For women with symptomatic HIV infection or CD4 cell counts below 200 cells per microliter, HAART was started earlier if possible. Treatment of the mothers was stopped at 6 months except for those mothers who needed HAART for their own health. The infants received ZDV + 3TC for 1 week after birth. Mothers were advised to exclusively breastfeed and to wean abruptly between 5 and 6 months. Transmission of HIV-1 was analyzed using the Kaplan-Meier survival technique. Cox regression was used for comparison with the breastfeeding population of the Petra trial arm A. Results:There were 441 infants included in the analysis of HIV-1 transmission. The cumulative transmission of HIV-1 was 4.1 % [95% confidence interval (CI): 2.2 to 6.0] at 6 weeks, 5.0% (95% CI: 2.9 to 7.1) at 6 months, and 6.0% (95% CI: 3.7 to 8.3) at 18 months after delivery. The cumulative risk of HIV transmission between 6 weeks and 6 months was 1.0% and between 6 months and 18 months 1.1%. The cumulative HIV infection or death rate was 8.6% (95% CI: 6.0 to 11.2) at 6 months and 13.6% (95% CI: 10.3 to 16.9) at 18 months after delivery. Viral load at enrollment and duration of HAART before delivery were significantly associated with transmission but CD4 cell count at enrollment was not. The median time of breastfeeding was 24 weeks. The transmission in the Mitra Plus study was about half of the transmission in the breastfeeding population in the Petra trial arm A at 6 months after delivery (adjusted relative hazard = 0.49, P < 0.001). The combined outcome HIV infection or death was significantly lower in the Mitra Plus study than in the breastfeeding population in the Petra trial arm A at 18 months (adjusted relative hazard = 0.61, P = 0.007). NVP-related mucocutaneous rash was demonstrated in 6.5% of 429 NVP-exposed women. The incidence of NVP-related grade 3 or 4 hepatotoxicity was low (0.5%). Conclusions:HAART given to HIV-infected mothers in late pregnancy and during breastfeeding resulted in a low postnatal HIV transmission similar to that previously demonstrated in the Mitra study in Dar es Salaam using infant prophylaxis with 3TC during breastfeeding. The extended maternal prophylaxis with HAART for prevention of mother-to-child transmission of HIV-1 for breastfeeding mothers who do not need HAART for their own health should be further evaluated and compared with the use of infant postnatal antiretroviral prophylaxis regarding safety and cost-effectiveness.

Broad Immunogenicity of a Multigene, Multiclade HIV-1 DNA Vaccine Boosted with Heterologous HIV-1 Recombinant Modified Vaccinia Virus Ankara

BACKGROUND A human immunodeficiency virus (HIV) vaccine that limits disease and transmission is urgently needed. This clinical trial evaluated the safety and immunogenicity of an HIV vaccine that combines a plasmid-DNA priming vaccine and a modified vaccinia virus Ankara (MVA) boosting vaccine. METHODS Forty healthy volunteers were injected with DNA plasmids containing gp160 of HIV-1 subtypes A, B, and C; rev B; p17/p24 gag A and B, and RTmut B by use of a needle-free injection system. The vaccine was administered intradermally or intramuscularly, with or without recombinant granulocyte macrophage colony-stimulating factor, and boosted with a heterologous MVA containing env, gag, and pol of CRF01A_E. Immune responses were monitored with HIV-specific interferon (IFN)-gamma and interleukin (IL)-2 ELISpot and lymphoproliferative assays (LPAs). RESULTS Vaccine-related adverse events were mild and tolerable. After receipt of the DNA priming vaccine, 11 (30%) of 37 vaccinees had HIV-specific IFN-gamma responses. After receipt of the MVA boosting vaccine, ELISpot assays showed that 34 (92%) of 37 vaccinees had HIV-specific IFN-gamma responses, 32 (86%) to Gag and 24 (65%) to Env. IFN-gamma production was detected in both the CD8(+) T cell compartment (5 of 9 selected vaccinees) and the CD4(+) T cell compartment (9 of 9). ELISpot results showed that 25 (68%) of 37 vaccinees had a positive IL-2 response and 35 (92%) of 38 had a positive LPA response. Of 38 subjects, a total of 37 (97%) were responders. One milligram of HIV-1 DNA administered intradermally was as effective as 4 mg administered intramuscularly in priming for the MVA boosting vaccine. CONCLUSION This HIV-DNA priming-MVA boosting approach is safe and highly immunogenic. TRIALS REGISTRATION International Standard Randomised Controlled Trial number: ISRCTN32604572 .

Diagnosis of primary HIV-1 infection and duration of follow-up after HIV exposure

ObjectiveTo determine the sensitivity of 33 currently available and seven earlier tests for the detection of HIV or HIV antibody in primary HIV-1 infection, to estimate the duration of the ‘window period’ and the influence of early initiated antiretroviral treatment (ART). DesignA prospective cohort study of 38 patients with primary HIV-1 infection. ART was initiated at a median time of 13 (range 0–23) days after the onset of symptoms in 10 patients. Main outcome measuresThe time from infection to onset of symptoms and from onset of symptoms to the appearance of HIV antibody as measured by 36 different tests, and the start and duration of viraemia, as detected by four different tests. ResultsThe illness appeared 13–15 days after infection in 12 of 15 determinable cases, and seroconversion was detected within 1–2 weeks after the onset of illness by 27 of 30 currently available tests for HIV antibody, in contrast to the 2–7 weeks or more needed by the old tests. HIV RNA appeared during the week preceding the onset of illness and was detected in all subsequent samples, except when ART had been initiated, which also induced a delay of the antibody response. ConclusionMany tests for HIV or HIV antibody can now be employed for an early confirmation of primary HIV infection (PHI). Currently available screening tests proved much more sensitive than older tests, and seroconversion was usually detected within one month after infection. Consequently, in Sweden we now recommend only 3 months of follow-up after most cases of HIV exposure.

Prevention of mother-to-child transmission of HIV-1 through breast-feeding by treating infants prophylactically with lamivudine in Dar es Salaam, Tanzania: the Mitra Study.

Objective:To investigate the possibility of reducing mother-to-child transmission (MTCT) of HIV-1 through breast-feeding by prophylactic antiretroviral (ARV) treatment of the infant during the breast-feeding period. Design:An open-label, nonrandomized, prospective cohort study in Tanzania (Mitra). Methods:HIV-1-infected pregnant women were treated according to regimen A of the Petra trial with zidovudine (ZDV) and lamivudine (3TC) from week 36 to 1 week postpartum. Infants were treated with ZDV and 3TC from birth to 1 week of age (Petra arm A) and then with 3TC alone during breast-feeding (maximum of 6 months). Counseling emphasized exclusive breast-feeding. HIV transmission was analyzed using the Kaplan-Meier survival technique. Cox regression was used for comparison with the breast-feeding population in arm A of the Petra trial, taking CD4 cell count and other possible confounders into consideration. Results:There were 398 infants included in the transmission analysis in the Mitra study. The estimated cumulative proportion of HIV-1-infected infants was 3.8% (95% confidence interval [CI]: 2.0 to 5.6) at week 6 after delivery and 4.9% (95% CI: 2.7 to 7.1) at month 6. The median time of breast-feeding was 18 weeks. High viral load and a low CD4 T-cell count at enrollment were associated with transmission. The Kaplan-Meier estimated risk of HIV-1 infection at 6 months in infants who were HIV-negative at 6 weeks was 1.2% (95% CI: 0.0 to 2.4). The cumulative HIV-1 infection or death rate at 6 months was 8.5% (95% CI: 5.7 to 11.4). No serious adverse events related to the ARV treatment of infants occurred. The HIV-1 transmission rate during breast-feeding in the Mitra study up to 6 months after delivery was more than 50% lower than in the breast-feeding population of Petra arm A (relative hazard = 2.61; P = 0.001; adjusted values). The difference in transmission up to 6 months was significant also in the subpopulation of mothers with CD4 counts ≥200 cells/μL. Conclusions:The rates of MTCT of HIV-1 in the Mitra study at 6 weeks and 6 months after delivery are among the lowest reported in a breast-feeding population in sub-Saharan Africa. Prophylactic 3TC treatment of infants to prevent MTCT of HIV during breast-feeding was well tolerated by the infants and could be a useful strategy to prevent breast milk transmission of HIV when mothers do not need ARV treatment for their own health.

A New Human Retrovirus Isolate of West African Origin (SBL-6669) and Its Relationship to HTLV-IV, LAV-II, and HTLV-IIIB

A new human retrovirus of West African origin (SBL-6669) has been isolated from a patient with immunological and clinical signs of immunodeficiency. Using radioimmunoprecipitation assays (RIPA) and Western blot (WB) tests with human sera, the new virus isolate has been compared with HTLV-IV, LAV-II, and the HTLV-IIIB prototype strain of the human immunodeficiency virus (HIV). The West African isolates appeared to be members of the same virus group since their glycoproteins were antigenically indistinguishable. West African sera showed no detectable cross reaction with HTLV-IIIB glycoproteins. The external glycoprotein in the different virus strains only showed minor variations in size. The size of the transmembranous protein was not unambiguously defined. In the West African virus isolates a 30-35 kD protein was seen similar to the protein previously described possibly to represent this component. However, in SBL-6669 a distinct 41 kD protein was also identified. There were interstrain variations in the size of several viral proteins among the West African virus isolates. Only minor differences were seen between SBL-6669 and LAV-II. The variations were most pronounced in two core proteins corresponding to the 19 kD and 24 kD proteins of HTLV-IIIB. In addition, West African human retroviruses appear to differ in pathogenicity. LAV-II and SBL-6669 are associated with immunodeficiency, whereas HTLV-IV was isolated from healthy individuals. Since further spread of these viruses to other parts of the world is imminent, it is necessary to consider their antigenic and immunogenic properties in serodiagnosis of HIV infections and in planning for immunoprophylactic interventions.

Oral candida albicans in HIV infection.

The prevalence of oral colonization with Candida albicans was studied in 225 homosexual men, 99 of whom had HIV antibodies and in 175 heterosexual men. Oral candidal carriage was most prevalent among HIV seropositive homosexual men (77.8%). Rich growth of C. albicans in culture and findings of pseudomycelial elements in oral mucosal smear also correlated with HIV seropositivity. Pseudomycelial forms of C. albicans were demonstrated in mucosal smear from all patients with oral mucosal lesions suspected for candidiasis. However, 26/53 patients (49.1%) with positive smear had no clinical signs of oral candidiasis. The oral yeast flora was sampled twice in 85 homosexual men at an interval of 12-18 months. 71/85 patients (83.5%) were grouped into the same category of candidal colonization; carrier or noncarrier state, on both occasions. No statistically significant differences in numbers of CD 4 cells or CD 8 cells were observed between patients with respect to candidal colonization, when HIV seropositive and seronegative homosexual men were considered separately.

Immunological changes in primary HIV-1 infection

Homosexual men with symptomatic primary HIV-1 infection displayed a pronounced lymphopaenia with significantly depressed numbers of CD3+, CD4+ and CD8+ cells and B cells during the first week of illness. Subsequently, the CD8+ cell counts rose in parallel with numbers of CD3+ cells, atypical lymphocytes and activated (CD38+ and HLA-Dr+) cells to attain maximal levels about a month following onset of illness. In contrast CD4+ and B cell numbers remained low for an extended period of time. Early signs of a host response included a transient appearance of interferon-alpha in the blood and raised levels of neopterin and beta 2-microglobulin (beta 2-M). Neither CD4+/CD8+ cell ratio nor beta 2-M resumed completely normal values during a follow-up period of 2 years. These findings shed some light on pathogenetic events during early HIV-1 infection and suggest that the infection, following the acute symptomatic stage, usually enters a stage of chronic active rather than latent infection.

Broad and potent immune responses to a low dose intradermal HIV-1 DNA boosted with HIV-1 recombinant MVA among healthy adults in Tanzania☆☆☆

BACKGROUND We conducted a phase I/II randomized placebo-controlled trial with the aim of exploring whether priming with a low intradermal dose of a multiclade, multigene HIV-1 DNA vaccine could improve the immunogenicity of the same vaccine given intramuscularly prior to boosting with a heterologous HIV-1 MVA among healthy adults in Dar es Salaam, Tanzania. METHODS Sixty HIV-uninfected volunteers were randomized to receive DNA plasmid vaccine 1mg intradermally (id), n=20, or 3.8mg intramuscularly (im), n=20, or placebo, n=20, using a needle-free injection device. DNA plasmids encoding HIV-1 genes gp160 subtype A, B, C; rev B; p17/p24 gag A, B and Rtmut B were given at weeks 0, 4 and 12. Recombinant MVA (10(8)pfu) expressing HIV-1 Env, Gag, Pol of CRF01_AE or placebo was administered im at month 9 and 21. RESULTS The vaccines were well tolerated. Two weeks after the third HIV-DNA injection, 22/38 (58%) vaccinees had IFN-γ ELISpot responses to Gag. Two weeks after the first HIV-MVA boost all 35 (100%) vaccinees responded to Gag and 31 (89%) to Env. Two to four weeks after the second HIV-MVA boost, 28/29 (97%) vaccinees had IFN-γ ELISpot responses, 27 (93%) to Gag and 23 (79%) to Env. The id-primed recipients had significantly higher responses to Env than im recipients. Intracellular cytokine staining for Gag-specific IFN-γ/IL-2 production showed both CD8(+) and CD4(+) T cell responses. All vaccinees had HIV-specific lymphoproliferative responses. All vaccinees reacted in diagnostic HIV serological tests and 26/29 (90%) had antibodies against gp160 after the second HIV-MVA boost. Furthermore, while all of 29 vaccinee sera were negative for neutralizing antibodies against clade B, C and CRF01_AE pseudoviruses in the TZM-bl neutralization assay, in a PBMC assay, the response rate ranged from 31% to 83% positives, depending upon the clade B or CRF01_AE virus tested. CONCLUSIONS This vaccine approach is safe and highly immunogenic. Low dose, id HIV-DNA priming elicited higher and broader cell-mediated immune responses to Env after HIV-MVA boost compared to a higher HIV-DNA priming dose given im. Three HIV-DNA priming immunizations followed by two HIV-MVA boosts efficiently induced Env-antibody responses.

Live attenuated simian immunodeficiency virus (SIV)mac in macaques can induce protection against mucosal infection with SIVsm.

Objective:To investigate whether vaccination of macaques with attenuated simian immunodeficiency virus (SIV)macC8 could induce long-term protective immunity against rectal exposure to SIVsm and intravenous exposure to the more divergent HIV-2. Design and methods:Eight months after vaccination with live attenuated SIVmacC8, four cynomolgus monkeys were challenged with SIVsm intrarectally and another four vaccinated monkeys were challenged with HIV-2 intravenously. Sixteen months after SIVmacC8 vaccination, another two monkeys were challenged with SIVsm across the rectal mucosa. Two vaccinees shown to be protected against SIVsm were rechallenged 8 months after the first challenge. Ten naive animals were used as controls. Serum antigenaemia, virus isolation, antibody responses, cell-mediated immunity and CD4+ and CD8+ T-cell subpopulations were monitored. PCR-based assays were used to distinguish between virus populations. Results:At the time of challenge, eight out of 10 vaccinees were PCR-positive for SIVmacC8 DNA but no virus could be isolated from peripheral blood mononuclear cells. After SIVsm challenge, three out of six vaccinees were repeatedly SIVsm PCR-negative. In one of the three infected monkeys, the challenge virus was initially suppressed but the monkey ultimately developed AIDS after increased replication of the pathogenic virus. Rechallenged monkeys remained protected. All HIV-2- challenged vaccinees became superinfected. All controls became infected with either SIVsm or HIV-2. At the time of challenge the vaccinees had neutralizing antibodies to SIVmac but no demonstrable cross-neutralizing antibodies to SIVsm or HIV-2. Titres of antigen-binding or neutralizing antibodies did not correlate with protection. Cytotoxic T-cell responses to SIV Gag/Pol and virus-specific T-cell proliferative responses were low. Conclusion:The live attenuated SIVmacC8 vaccine was able to induce long-term protection against heterologous intrarectal SIVsm challenge in a proportion of macaques but not against the more divergent HIV-2, which was given intravenously.