Whilst the production of IFN-γ by CD4+ T cells is vital  and , it is not sufficient, and a more complex picture is emerging involving multiple cytokines see more and T cell subsets, including regulatory T cells , , ,  and . Several small human studies have compared immune responses
to different BCG strains, with variable results , , , , , , ,  and , including two in Africa, which demonstrated some variability in T cell proliferation and interferon-gamma (IFN-γ) production depending on the strain and route of administration ,  and . Besides TB, there is evidence that BCG may also provide protection against other illnesses, with studies showing lower rates of malaria, acute lower respiratory tract infection and overall mortality in BCG-immunised individuals , ,  and . Such non-specific effects of BCG have also been demonstrated immunologically, with increased cytokine responses to both BCG-related antigens and non-BCG antigens such as tetanus toxoid (TT) or phytohaemagglutinin (PHA) amongst BCG-immunised children  and . Our large birth cohort in Entebbe, Uganda, provided an opportunity to examine whether different BCG strains elicited different immune responses to both mycobacterial and non-mycobacterial stimuli, and to evaluate further the relationship between BCG strain, scarring and cytokine responses. The Entebbe
Mother and Baby Study, a randomised double-blind, placebo-controlled trial of the effect of anthelminthic treatment on responses to childhood immunisations, www.selleckchem.com/products/bmn-673.html has been described elsewhere , , others  and ; the following methods are relevant to this analysis. Pregnant women from the Entebbe peninsula in Uganda were screened and enrolled at Entebbe Hospital from April 2003 until November 2005. Socio-demographic details were obtained by questionnaire during antenatal care. Stool and blood samples were taken for parasitological and HIV
testing and babies of participating mothers were followed up. Second-born twins, babies who had not received all three doses of tetanus vaccine and babies who had received their BCG after 6 months or outside Entebbe Hospital (where strain data were unavailable) were excluded from this analysis. The HIV status of HIV-exposed infants was ascertained through PCR of blood taken at age 6 weeks and rapid-test serology performed at 18 months. At age 12 months infants had blood taken for immunological analysis; anthropometric parameters and the presence and diameter of BCG scars were documented. If unwell at the time of the visit, infants were treated accordingly and the study investigations were conducted up to 2 months later. Throughout the study the clinic was freely accessible as required, with any illnesses or vaccine-related adverse events being recorded. Vaccines were provided by Uganda National Medical Stores. Nurses at Entebbe Hospital immunised babies at birth with 0.