Immune memory to Sudan virus: comparison between two separate disease outbreaks.

Recovery from ebolavirus infection in humans is associated with the development of both cell-mediated and humoral immune responses. According to recent studies, individuals that did not survive infection with ebolaviruses appear to have lacked a robust adaptive immune response and the expression of several early innate response markers. However, a comprehensive protective immune profile has yet to be described. Here, we examine cellular memory immune responses among survivors of two separate Ebolavirus outbreaks (EVDs) due to Sudan virus (SUDV) infection in Uganda-Gulu 2000-2001 and Kibaale 2012. Freshly collected blood samples were stimulated with inactivated SUDV, as well as with recombinant SUDV or Ebola virus (EBOV) GP (GP1-649). In addition, ELISA and plaque reduction neutralization assays were performed to determine anti-SUDV IgG titers and neutralization capacity. Cytokine expression was measured in whole blood cultures in response to SUDV and SUDV GP stimulation in both survivor pools, demonstrating recall responses that indicate immune memory. Cytokine responses between groups were similar but had distinct differences. Neutralizing, SUDV-specific IgG activity against irradiated SUDV and SUDV recombinant proteins were detected in both survivor cohorts. Furthermore, humoral and cell-mediated crossreactivity to EBOV and EBOV recombinant GP1-649 was observed in both cohorts. In conclusion, immune responses in both groups of survivors demonstrate persistent recognition of relevant antigens, albeit larger cohorts are required in order to reach greater statistical significance. The differing cytokine responses between Gulu and Kibaale outbreak survivors suggests that each outbreak may not yield identical memory responses and promotes the merits of studying the immune responses among outbreaks of the same virus. Finally, our demonstration of cross-reactive immune recognition suggests that there is potential for developing cross-protective vaccines for ebolaviruses.

Human herpesvirus 8 infection in children and adults in a population-based study in rural Uganda.

BACKGROUND: Human herpesvirus 8 (HHV-8) infection is endemic in sub-Saharan Africa. We examined sociodemographic, behavioral, and biological factors associated with HHV-8 infection in children and adults to determine HHV-8 seroprevalence and potential routes of transmission. METHODS: Participants were 1383 children and 1477 adults from a population-based sample in a rural community in Uganda. Serum samples were tested for HHV-8 antibodies with use of an enzyme immunoassay against K8.1. RESULTS: HHV-8 seroprevalence increased from 16% among children aged 1.5-2 years to 32% among children aged 10-13 years (P <.001) and from 37% among participants aged 14-19 years to 49% among adults aged ≥ 50 years (P <.05). HHV-8 seropositivity in children was independently associated with residing with a seropositive parent (P < .001) and residing with ≥ 1 other seropositive child aged <14 years (P < .001). History of sharing food and/or sauce plates was marginally associated with HHV-8 infection in children (P = .05). Among 1404 participants aged ≥ 15 years , there was no association between correlates of sexual behavior (eg, number of lifetime sex partners and HIV infection) and HHV-8 seropositivity (P > .10). CONCLUSIONS: Our data suggest that HHV-8 is acquired primarily through horizontal transmission in childhood from intrafamilial contacts and that transmission continues into adulthood potentially through nonsexual routes.

Identification of HIV-1 infected infants and young children using real-time RT PCR and dried blood spots from Uganda and Cameroon.

Serodiagnosis of HIV infection in infants born to HIV-infected mothers is problematic due to the prolonged presence of maternal antibodies in infants. Nucleic acid-based amplification assays have been used to overcome this problem. Here a simplified, one-tube, real-time, duplex reverse transcription PCR (RT PCR) assay is shown to detect HIV-1 total nucleic acid (TNA) isolated from dried blood spots. The detection of TNA, as opposed to DNA alone, increases the HIV target molecules and thus makes the assay more robust. This method was used to detect HIV from the DBS collected from HIV-1 exposed infants and young children in Uganda (n=128) and Cameroon (n=315). The gold-standards used were a plasma viral assay in Uganda and Amplicor DNA assay in Cameroon. The concordance of this real-time assay and the gold standards was 99.2% (127/128) and 99.4% (313/315) with the Ugandan and Cameroonian samples, respectively. This simple and cost-effective assay is potentially useful for the diagnosis of pediatric HIV infection and for evaluating programs to reduce mother-to-child transmission of HIV-1.