Browsing by Author "Sebina, Ismail"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Mycobacterium Tuberculosis Infection Boosts B Cell 2 Responses to Unrelated Pathogens
    (bioRxiv, 2019) Kimuda, Simon G.; Andia-Biraro, Irene; Sebina, Ismail; Egesa, Moses; Nalwoga, Angela; Bagaya, Bernard S.; Elliott, Alison M.; Cose, Stephen
    Antigens from Mycobacterium tuberculosis (M.tb), have been shown to stimulate human B cell responses to unrelated recall antigens in vitro. However, it is not known whether natural M.tb infection or whether vaccination with the related species, Mycobacterium bovis BCG, has a similar effect. This study investigated the effects of M.tb infection and BCG vaccination on B cell responses to heterologous pathogen recall antigens. Antibodies against several bacterial and viral pathogens were quantified by ELISA in 68 uninfected controls, 62 individuals with latent TB infection (LTBI) and 107 active pulmonary TB (APTB) cases, and 24 recently BCG-vaccinated adolescents and naive controls. Antibody avidity was investigated using surface plasmon resonance and B cell ELISPOT assays were used to measure plasmablast and memory B cell responses (MBC) in APTB cases and healthy donor controls. APTB was associated with higher levels of antibodies to tetanus toxoid (TT), diphtheria toxoid, respiratory syncytial virus, measles virus and Kaposi’s sarcoma herpesvirus, compared to uninfected controls. Vaccination with BCG did not alter levels of antibodies against heterologous pathogens. TT-specific antibody avidity was increased in APTB and the ratio of TT-specific plasmablasts to MBCs in the APTB cases was 7:1. M.tb infection boosts serological memory to heterologous pathogens in human subjects and this process may be driven by polyclonal activation of memory B cells.
  • Thumbnail Image
    Item
    Mycobacterium Tuberculosis Infection is Associated with Increased B Cell Responses to Unrelated Pathogens
    (Scientific reports, 2020) Kimuda, Simon G.; Andia‑Biraro, Irene; Sebina, Ismail; Egesa, Moses; Nalwoga, Angela; Smith, Steven G.; Bagaya, Bernard S.; Levin, Jonathan; Elliott, Alison M.; Cose, Stephen
    Antigens from Mycobacterium tuberculosis (M.tb), have been shown to stimulate human B cell responses to unrelated recall antigens in vitro. However, it is not known whether natural M.tb infection or whether vaccination with, Mycobacterium bovis BCG, has a similar efect. This study investigated the efects of M.tb infection and BCG vaccination on B cell responses to heterologous pathogen recall antigens. Antibodies against several bacterial and viral pathogens were quantifed by ELISA in 68 uninfected controls, 62 individuals with latent TB infection (LTBI) and 107 active pulmonary TB (APTB) cases, and 24 recently BCG-vaccinated adolescents and naive controls. Antibody avidity was investigated using surface plasmon resonance and B cell ELISPOTs were used to measure plasmablast and memory B cell responses (MBC) in APTB cases and healthy donor controls. APTB was associated with higher levels of antibodies to respiratory syncytial virus and measles virus, compared to uninfected controls. BCG vaccination did not alter levels of antibodies against heterologous pathogens. Tetanus toxoid (TT)-specifc antibody avidity was increased in APTB cases in comparison to uninfected individuals and the ratio of TT-specifc plasmablasts to MBCs in the APTB cases was 7:1. M.tb infection is associated with increased antibody responses to heterologous pathogens in human subjects.
  • Thumbnail Image
    Item
    Parasite infection is associated with Kaposi’s sarcoma associated herpesvirus (KSHV) in Ugandan women
    (Infectious Agents and Cancer, 2011) Wakeham, Katie; Webb, Emily L.; Sebina, Ismail; Muhangi, Lawrence; Miley, Wendell; Johnson, W. Thomas; Ndibazza, Juliet; Elliott, Alison M.; Whitby, Denise; Newton, Robert
    Immune modulation by parasites may influence susceptibility to bacteria and viruses. We examined the association between current parasite infections, HIV and syphilis (measured in blood or stool samples using standard methods) and antibodies against Kaposi’s sarcoma herpesvirus (KSHV), measured by ELISA, in 1915 stored plasma samples from pregnant women in Entebbe, Uganda. Seroprevalence of KSHV was higher in women with malaria parasitaemia (73% vs 60% p = 0.01), hookworm (67% vs 56% p = 0.001) and Mansonella perstans (69% vs 59% p = 0.05); seroprevalence increased with increasing intensity of hookworm infection (p < 0.001[trend]). No associations were found for HIV, five other parasites or active syphilis. These effects were not explained by socioeconomic status or education. Specific parasite infections are associated with presence of antibodies against KSHV, perhaps mediated via their effect on immune function.
  • Thumbnail Image
    Item
    Risk Factors for Seropositivity to Kaposi Sarcoma–Associated Herpesvirus Among Children in Uganda
    (Journal of acquired immune deficiency syndromes, 2013) Wakeham, Katie; Webb, Emily L.; Sebina, Ismail; Nalwoga, Angela; Muhangi, Lawrence; Miley, Wendell; Johnston, W. Thomas; Ndibazza, Juliet; Whitby, Denise; Newton, Robert; Elliott, Alison M.
    Determinants of Kaposi sarcoma–associated herpesvirus (KSHV) seropositivity among children living in sub-Saharan African populations where infection is endemic are not well understood. Local environmental factors, including other infectious agents, may be key. Within the context of a well-characterized birth cohort, we examined associations between various factors and antibodies against KSHV, measured in stored plasma samples from 1823 mother–child pairs in Entebbe, Uganda.