A CD4+CD161+ T-Cell Subset Present in Unexposed Humans, Not Tb Patients, Are Fast Acting Cells That Inhibit the Growth of Intracellular Mycobacteria Involving CD161 Pathway, Perforin, and IFN-γ/Autophagy
Authors: Hongbo Shen
Ling Shen
Lan Yao
Jiang Pi
Rui Yang
Enzhuo Yang
Yidian Liu
Robert L Modlin
Zheng W Chen
Ying Peng
Xiaona Shen
Wei Sha
Journal: Frontiers in Immunology (2021)
Discipline: IMMUNOLOGY
Keywords: CD4+CD161+ T cells; IFN-γ; killing intracellular bacteria; perforin; tuberculosis.
Affiliations: Clinic and Research Center of Tuberculosis, Shanghai Key Lab of Tuberculosis, Shanghai Pulmonary Hospital, Institute for Advanced Study, Tongji University School of Medicine, Shanghai, China., Wuhan YZY Biopharma Co., Ltd, Biolake, Wuhan, China., Department of Microbiology and Immunology, Center for Primate Biomedical Research, University of Illinois College of Medicine, Chicago, IL, United States., Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, United States.

Abstract:  It remains undefined whether a subset of CD4+ T cells can function as fast-acting cells to control Mycobacterium tuberculosis (Mtb) infection. Here we show that the primary CD4+CD161+ T-cell subset, not CD4+CD161-, in unexposed healthy humans fast acted as unconventional T cells capable of inhibiting intracellular Mtb and BCG growth upon exposure to infected autologous and allogeneic macrophages or lung epithelial A549 cells. Such inhibition coincided with the ability of primary CD4+CD161+ T cells to rapidly express/secrete anti-TB cytokines including IFN-γ, TNF-α, IL-17, and perforin upon exposure to Mtb. Mechanistically, blockades of CD161 pathway, perforin or IFN-γ by blocking mAbs abrogated the ability of CD4+CD161+ T cells to inhibit intracellular mycobacterial growth. Pre-treatment of infected macrophages with inhibitors of autophagy also blocked the CD4+CD161+ T cell-mediated growth inhibition of mycobacteria. Furthermore, adoptive transfer of human CD4+CD161+ T cells conferred protective immunity against mycobacterial infection in SCID mice. Surprisingly, CD4+CD161+ T cells in TB patients exhibited a loss or reduction of their capabilities to produce perforin/IFN-γ and to inhibit intracellular growth of mycobacteria in infected macrophages. These immune dysfunctions were consistent with PD1/Tim3 up-regulation on CD4+CD161+ T cells in active tuberculosis patients, and the blockade of PD1/Tim3 on this subset cells enhanced the inhibition of intracellular mycobacteria survival. Thus, these findings suggest that a fast-acting primary CD4+CD161+T-cell subset in unexposed humans employs the CD161 pathway, perforin, and IFN-γ/autophagy to inhibit the growth of intracellular mycobacteria, thereby distinguishing them from the slow adaptive responses of conventional CD4+ T cells. The presence of fast-acting CD4+CD161+ T-cell that inhibit mycobacterial growth in unexposed humans but not TB patients also implicates the role of these cells in protective immunity against initial Mtb infection. 

Retracted: No

PubPeer comments:
 In this publication the authors are comparing the mortality due to respiratory diseases between **2018-2019** and **2019-2020** (**weeks 47 to 14**). Since Covid-19 epidemic was called a pandemic on March 11 2020 (Week 11), the **choice of this time intervals should be discussed more in depth**, since it does not seem relevant at first. . To summarize, the authors intend to compare a 19 weeks period from 2018-2019 to a same length period in 2019-2020 which includes 3 weeks of a pandemic, in an area where the pandemic started late as we ll see it later. Thus, **the choice of this arbitrary period is not significative** and the authorsu2019 conclusion trying to u201c*put into perspective the death burden of SARS-CoV-2 infections in this geographical area*u201d are therefore not relevant, as **they write it by themselves** when stating that u201c*The number of SARS-CoV-2-associated deaths will grow after the timeframe*u201d. The authors conclusion is that u201c*the number of SARS-CoV-2-associated deaths was similar to that of deaths associated with other viral respiratory infections between December 2019 and March 2020, and lower than that of deaths associated with viral respiratory infections between December 2018 and March 2019*u201d. Despite stating that u201c*This drop was essentially due to a significant decrease in influenza*u201d, **the authors did not see the deaths due to Covid-19**. Despite not being clearly visible in their region, **the authors should have taken into account the exponential growth** of the deaths from Covid-19, clearly visible by the end of week 14 they use for their article: ![file] Furthermore, when **revising this article on April 25th 2020**, the authors should have realized that the death burden due to Covid 19 was much higher than the figures they used to support their hypothesis, and **this should have led them to more cautious statements**. ![file] Source for both graphs: https: ourworldindata.org coronavirus country france Furthermore, it should be noted that this epidemic, in France, started in the u201cgrand estu201d, which means north-eastern part of the country, **the epidemic in Marseille starting much slower and much later** with more than the double of number of cases that the authors report (In French: https: actu.fr societe coronavirus coronavirus-2-643-cas-dans-grand-est-93-deces-situation-saggrave_32413735.html ). Thus, **neither the timeframe nor the geographical area being pertinent, the conclusions drawn by the authors are not useful**, since they only showed that before the onset of the pandemic, the death burden due to respiratory diseases was almost constant. **No conclusion on the Covid-19 pandemic can drawn made from this article**. Furthermore, **the death burden of Covid-19 was already clearly visible around half of march in public statistics**: ![file] https: www.insee.fr fr statistiques 4500439?sommaire=4487854 One can thus wonder why the authors, revising their manuscript on, April 25th did not take this evolution into account. We can then conclude that not seing the death burden of a pandemic outside this pandemic is normal, but **we can question the relevance of this article**. ,