Genetic defects in the IFN-γ response pathway cause unique susceptibility to intracellular pathogens, particularly mycobacteria, but are rare and do not explain mycobacterial disease in the majority of affected patients. We postulated that acquired defects in macrophage activation by IFN-γ may cause a similar immunological phenotype and thus explain the occurrence of disseminated intracellular infections in some patients without identifiable immune deficiency. Macrophage activation in response to IFN-γ and IFN-γ production were studied in whole blood and PBMCs of 3 patients with severe, unexplained nontuberculous mycobacterial infection. In all 3 patients, IFN-γ was undetectable following mitogen stimulation of whole blood, but significant quantities were detectable in the supernatants of PBMCs when stimulated in the absence of the patients' own plasma. The patients' plasma inhibited the ability of IFN-γ to increase production of TNF-α by both autologous and normal donor PBMCs, and recovery of exogenous IFN-γ from the patients' plasma was greatly reduced. Using affinity chromatography, surface-enhanced laser desorption/ionization mass spectrometry, and sequencing, we isolated an IFN-γ-neutralizing factor from the patients' plasma and showed it to be an autoantibody against IFN-γ. The purified anti-IFN-γ antibody was shown to be functional first in blocking the upregulation of TNF-α production in response to endotoxin; second in blocking induction of IFN-γ-inducible genes (according to results of high-density cDNA microarrays); and third in inhibiting upregulation of HLA class II expression on PBMCs. Acquired defects in the IFN-γ pathway may explain unusual susceptibility to intracellular pathogens in other patients without underlying, genetically determined immunological defects.

Breast cancer remains one of the leading causes of cancer-associated death worldwide. Conventional treatment is associated with substantial toxicity and suboptimal efficacy. We, therefore, developed and evaluated the in vitro efficacy of an autologous dendritic cell (DC) vaccine to treat breast cancer. We recruited 12 female patients with stage 1, 2, or 3 breast cancer and matured their DCs with autologous tumour-specific lysate, a toll-like receptor (TLR)-3 and 7/8 agonist, and an interferon-containing cocktail. The efficacy of the vaccine was evaluated by its ability to elicit a cytotoxic T-lymphocyte response to autologous breast cancer cells in vitro. Matured DCs (≥ 60% upregulation of CD80, CD86, CD83, and CCR7) produced high levels of the Th1 effector cytokine, IL12-p70 (1.2 ng/ml; p < 0.0001), compared to DCs pulsed with tumour lysate, or matured with an interferon-containing cocktail alone. We further showed that matured DCs enhance antigen-specific CD8 + T-cell responses to HER-2 (4.5%; p < 0.005) and MUC-1 (19%; p < 0.05) tetramers. The mature DCs could elicit a robust and dose-dependent antigen-specific cytotoxic T-lymphocyte response (65%) which was tumoricidal to autologous breast cancer cells in vitro compared to T-lymphocytes that were primed with autologous lysate loaded-DCs (p < 0.005). Lastly, we showed that the mature DCs post-cryopreservation maintained high viability, maintained their mature phenotype, and remained free of endotoxins or mycoplasma. We have developed a DC vaccine that is cytotoxic to autologous breast cancer cells in vitro. The tools and technology generated here will now be applied to a phase I/IIa clinical trial.Electronic supplementary materialThe online version of this article (10.1007/s00262-018-2238-5) contains supplementary material, which is available to authorized users.

Background The effects of the widely used progestin-only injectable contraceptives, medroxyprogesterone acetate (MPA) and norethisterone acetate (NET-A), on host susceptibility to Mycobacterium tuberculosis ( Mtb ) are unknown. Methods We recruited human immunodeficiency virus–uninfected females, not taking any contraceptives, from Cape Town, South Africa, to evaluate the effect of MPA, NET-A, and dexamethasone on Mtb containment in monocyte-derived macrophages co-incubated with purified protein derivative (PPD)–driven peripheral blood–derived effector cells. Results MPA ( P < .005) and dexamethasone ( P < .01), but not NET-A, significantly attenuated Mtb containment in Mtb -infected macrophages co-cultured with PPD-driven effector cells at physiologically relevant concentrations and in a dose-dependent manner. Antagonizing the glucocorticoid receptor with mifepristone (RU486) abrogated the reduction in Mtb containment. In PPD-stimulated peripheral blood mononuclear cells, MPA and dexamethasone, but not NET-A, upregulated (median [interquartile range]) regulatory T cells (5.3% [3.1%–18.2%]; P < .05), reduced CD4 + T-cell interferon-γ (21% [0.5%–28%]; P < .05) and granzyme B production (12.6% [7%–13.5%]; P < .05), and reduced CD8 + perforin activity (2.2% [0.1%–7%]; P < .05). RU486 reversed regulatory T-cell up-regulation and the inhibitory effect on Th1 and granzyme/perforin-related pathways. Conclusions MPA, but not NET-A, subverts mycobacterial containment in vitro and downregulates pathways associated with protective CD8 + - and CD4 + -related host immunity via the glucocorticoid receptor. These data potentially inform the selection and use of injectable contraceptives in tuberculosis-endemic countries.

The immunopathogenesis of severe COVID-19 is incompletely understood. In contradistinction to the upper respiratory tract where replicating (culturable) SARS-CoV-2 is recoverable approximately ~ 4 to 8 days after symptom onset, there is paucity of data about the frequency or duration of replicating virus in the lower respiratory tract (the human lung). We undertook lung tissue sampling (needle biopsy), within ~2 hours of death, in 42 mechanically ventilated decedents during the Beta and Delta waves. Lung biopsy cores underwent viral culture, histopathological analysis, electron microscopy, transcriptomic profiling, immunohistochemistry and cell-based flow cytometry of deconstructed tissue. 38% (16/42) of patients had culturable virus in the lung (persisting for up to 4 weeks after symptom onset). This, hitherto, undescribed bio-phenotype of lung-specific persisting viral replication was associated with an enhanced pulmonary pro-inflammatory response and variant-specific increased rates of bacterial bronchopneumonia and accelerated death. These findings question existing paradigms and suggest that in a subset of patients, concurrent, rather than sequential active viral replication continues to drive a heightened pro-inflammatory response. Our findings have potential implications for the design of therapeutic interventional strategies and clinical management of severe COVID-19 disease.