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Several respiratory viruses can circulate during the same period and can concurrently or sequentially infect the respiratory tract, leading to virus-virus interactions. At the host level, the course of infection [...]

Author(s): Myriam El Biali (corresponding author) [a]; Barbara Broers [b]; Marie Besson [a]; Jules Demeules [a] Introduction Since the end of the year 2019, the world is confronted with a [...], Since the endocannabinoid system is involved in immune function, the effect of cannabinoid intake on infectious conditions is questioned for several years and is of particular interest in the COVID 19 pandemia. Some data suggest that the immunomodulatory effect of cannabinoids may affect the course and severity of SARS-CoV-2 infection. Given the large number of cannabinoids consumers in the community, this commentary presents the current knowledge on the potential impact of cannabinoids and endocannabinoids on bacterial and viral infection courses namely SARS-CoV-2 disease. Practical recommendations, which can be drawn from the literature, are given. Keywords: SARS-CoV-2, COVID-19, Immunity, Cannabinoids, Endocannabinoid system

One of the most serious consequences of infectious diseases is their potential to be transmitted from pregnant women to their unborn fetuses. The occurrence of this process--intrauterine vertical transmission--has been [...], Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the agent of coronavirus disease 2019 (COVID-19), is similar to 2 other coronaviruses, SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV), in causing life-threatening maternal respiratory infections and systemic complications. Because of global concern for potential intrauterine transmission of SARS-CoV-2 from pregnant women to their infants, this report analyzes the effects on pregnancy of infections caused by SARS-CoV-2 and other respiratory RNA viruses, and examines the frequency of maternal-fetal transmission with SARS-CoV-2, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), influenza, respiratory syncytial virus (RSV), parainfluenza (HPIV), and metapneumovirus (hMPV). There have been no confirmed cases of intrauterine transmission reported with SARS-CoV-2 or any other coronaviruses--SARS and MERS. Influenza virus, despite causing approximately 1 billion annual infections globally, has only a few cases of confirmed or suspected intrauterine fetal infections reported. Respiratory syncytial virus is an unusual cause of illness among pregnant women, and with the exception of 1 premature infant with congenital pneumonia, no other cases of maternal-fetal infection are described. Parainfluenza virus and hMPV can produce symptomatic maternal infections but do not cause intrauterine fetal infection. In summary, it appears that the absence thus far of maternal-fetal transmission of the SARS-CoV-2 virus during the COVID-19 pandemic is similar to other coronaviruses, and is also consistent with the extreme rarity of suggested or confirmed cases of intrauterine transmission of other respiratory RNA viruses. This observation has important consequences for pregnant women because it appears that if intrauterine transmission of SARS-CoV-2 does eventually occur, it will be a rare event. Potential mechanisms of fetal protection from maternal viral infections are also discussed. (Arch Pathol Lab Med. 2020;144:920-928; doi: 10.5858/arpa.2020-0211-SA)

Central nervous system (CNS) infections, which can be caused by a number of different viruses, bacteria, fungi, and parasites, cause substantial disease and death in Southeast Asia (1). The etiologies [...]

IntroductionAlthough social scientists have long worked in public health emergencies, the value of including social science intelligence in response strategies became highly visible during the epidemic of Ebola virus disease [...]

Introduction Myeloid-derived suppressor cells (MDSCs) with potent immune-suppressive activity are widely implicated in negative regulation of immune responses in many pathological conditions including cancer, chronic inflammation, infections, autoimmune diseases, and [...], Myeloid-derived suppressor cells (MDSCs) are major negative regulators of immune responses in cancer and chronic infections. It remains unclear if regulation of MDSC activity in different conditions is controlled by similar mechanisms. We compared MDSCs in mice with cancer and lymphocytic choriomeningitis virus (LCMV) infection. Chronic LCMV infection caused the development of monocytic MDSCs (M-MDSCs) but did not induce polymorphonuclear MDSCs (PMN-MDSCs). In contrast, both MDSC populations were present in cancer models. An acquisition of immune-suppressive activity by PMN-MDSCs in cancer was controlled by IRE1[alpha] and ATF6 pathways of the endoplasmic reticulum (ER) stress response. Abrogation of PMN-MDSC activity by blockade of the ER stress response resulted in an increase in tumor-specific immune response and reduced tumor progression. In contrast, the ER stress response was dispensable for suppressive activity of M-MDSCs in cancer and LCMV infection. Acquisition of immune-suppressive activity by M-MDSCs in spleens was mediated by IFN-[gamma] signaling. However, it was dispensable for suppressive activity of M-MDSCs in tumor tissues. Suppressive activity of M-MDSCs in tumors was retained due to the effect of IL-6 present at high concentrations in the tumor site. These results demonstrate disease- and population-specific mechanisms of MDSC accumulation and the need for targeting different pathways to achieve inactivation of these cells.

The most recent Ebola virus disease (EVD) outbreak in West Africa is the largest outbreak in history. As of March 27, 2016, an estimated 3,956 persons in Sierra Leone had [...]

In 1976, the investigation of concurrent outbreaks of a hemorrhagic fever syndrome (Ebola virus disease [EVD]) in Zaire (currently Democratic Republic of Congo) and Sudan (currently Republic of South Sudan) [...]

Author(s): Norifumi Iijima [sup.1] , Akiko Iwasaki [sup.1] [sup.1] Author Affiliations: (1) Department of Immunobiology, Howard Hughes Medical Institute, Yale School of Medicine, New Haven, USA Main To investigate the [...], Interferon-[gamma]-secreting CD4.sup.+ helper T cells are required for antibody access to neuronal tissues in response to neurotropic virus infections. CD4 T cells enable antibody delivery to neuronal tissue Norifumi Iijima and Akiko Iwasaki investigate the mechanism of antibody-mediated protection within barrier-protected tissues using a mouse model of genital herpes infection. They find that interferon-[gamma]-secreting CD4.sup.+ helper T cells are required for antibody access to neuronal tissues in response to challenge with herpes simplex virus 2. These results point to a previously unappreciated role of CD4.sup.+ T cells in mobilizing antibodies to the peripheral sites of infection where they help to limit viral spread. Circulating antibodies can access most tissues to mediate surveillance and elimination of invading pathogens. Immunoprivileged tissues such as the brain and the peripheral nervous system are shielded from plasma proteins by the blood-brain barrier.sup.1 and blood-nerve barrier.sup.2, respectively. Yet, circulating antibodies must somehow gain access to these tissues to mediate their antimicrobial functions. Here we examine the mechanism by which antibodies gain access to neuronal tissues to control infection. Using a mouse model of genital herpes infection, we demonstrate that both antibodies and CD4 T cells are required to protect the host after immunization at a distal site. We show that memory CD4 T cells migrate to the dorsal root ganglia and spinal cord in response to infection with herpes simplex virus type 2. Once inside these neuronal tissues, CD4 T cells secrete interferon-[gamma] and mediate local increase in vascular permeability, enabling antibody access for viral control. A similar requirement for CD4 T cells for antibody access to the brain is observed after intranasal challenge with vesicular stomatitis virus. Our results reveal a previously unappreciated role of CD4 T cells in mobilizing antibodies to the peripheral sites of infection where they help to limit viral spread.