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Human immunodeficiency virus infection leads to lower frequencies of CD4+ T cells specific for Mycobacterium tuberculosis in blood and lungs. However, an influx of T cells to the lungs results in similar absolute numbers of specific CD4+ T cells, compared with uninfected individuals., Human immunodeficiency virus type 1 (HIV) infection substantially increases the risk of developing tuberculosis. There is extensive depletion of Mycobacterium tuberculosis–specific CD4+ T cells in blood during early HIV infection, but little is known about responses in the lungs at this stage. Given that mucosal organs are a principal target for HIV-mediated CD4+ T-cell destruction, we investigated M. tuberculosis–specific responses in bronchoalveolar lavage (BAL) from persons with latent M. tuberculosis infection and untreated HIV coinfection with preserved CD4+ T-cell counts. M. tuberculosis–specific CD4+ T-cell cytokine (interferon γ, tumor necrosis factor α, and interleukin 2) responses were discordant in frequency and function between BAL and blood. Responses in BAL were 15-fold lower in HIV-infected persons as compared to uninfected persons (P = .048), whereas blood responses were 2-fold lower (P = .006). However, an increase in T cells in the airways in HIV-infected persons resulted in the overall number of M. tuberculosis–specific CD4+ T cells in BAL being similar. Our study highlights the important insights gained from studying M. tuberculosis immunity at the site of disease during HIV infection.

Item does not contain fulltext The contribution of fungal infections to the morbidity and mortality of HIV-infected individuals is largely unrecognized. A recent meeting highlighted several priorities that need to be urgently addressed, including improved epidemiological surveillance, increased availability of existing diagnostics and drugs, more training in the field of medical mycology, and better funding for research and provision of treatment, particularly in developing countries.

Chlamydia trachomatis (C. trachomatis) is the most common bacterial sexually transmitted pathogen worldwide, especially in low- and middle-income countries, including South Africa. Although frequently asymptomatic, C. trachomatis infections in women cause pronounced genital inflammation. Given that genital inflammation increases women's risk for human immunodeficiency virus (HIV) infection, treating and preventing chlamydia is vital. Thus, there is an urgent need for effective interventions to curb chlamydia infection. Although vaccines are currently in development, none are yet approved for use. New drugs should also be developed and tested given the general rise of antimicrobial resistance. To advance such interventions, expertise in the basic microbiology of C. trachomatis is required. Techniques have indeed advanced over time; however, the standard methods of culture and quantification of C. trachomatis in vitro remain challenging. In South Africa, expertise in C. trachomatis culture and in vitro manipulation is particularly limited. Therefore, I aimed to establish a method to quantify laboratory-adapted stocks of C. trachomatis in in vitro cell culture, to develop research capacity and set the stage for the important future research needed to combat this pathogen. In this study, C. trachomatis was cultured from existing laboratory stocks and used to optimise and compare microscopy-based quantification methods. First, representative C. trachomatis urogenital serovars (E, H) and lymphogranuloma venereum (LGV) serovars (L1 and L2) were propagated in McCoy cells, using an established centrifugation protocol. These stocks were used for all assays comparing three commercially available reagents: (1) Pathfinder's C. trachomatis monoclonal antibody, (2) Invitrogen's C. trachomatis major outer membrane protein (MOMP) antibodies, and (3) Trinity Biotech MicroTrak C. trachomatis culture confirmation kit. In the research setting, fluorescent microscopy techniques are widely used for quantification of C. trachomatis due to their high sensitivity. However, this study showed the Pathfinder C. trachomatis monoclonal antibody kit and Invitrogen's C. trachomatis MOMP Monoclonal Antibody kits had poor sensitivity with high background fluorescent signals. Invitrogen's polyclonal antibody yielded inconsistent results, being either very weakly fluorescent or giving extremely bright signals. Thus, counting bacteria using this polyclonal antibody had limited success and results were not reproducible. MicroTrak's kit, in contrast, allowed for clear visualisation of inclusions and allowed for consistent and successful counting of C. trachomatis bacteria. This study reports inconsistent and/or unreliable results from the kits tested, with two of the three reagents performing poorly. The last, effective kit manufactured by MicroTrak was since discontinued. Thus, molecular methods, particularly qPCRbased methods should be utilised to quantify C. trachomatis in future in vitro cell culture studies.