A simple method for the in situ detection of eosinophils

Along with the human respiratory syncytial virus (hRSV), the human metapneumovirus (hMPV) is one of the leading causes of childhood hospitalization and a major health burden worldwide. Unfortunately, owing to an inefficient immunological memory, hMPV infection provides limited immune protection against reinfection. Furthermore, hMPV can induce an inadequate Th2 type immune response that causes severe lung inflammation, leading to airway obstruction. Similar to hRSV, it is likely that an effective clearance of hMPV would require a balanced Th1 type immunity by the host, involving the activation of IFN-γ–secreting T cells. A recognized inducer of Th1 immunity is Mycobacterium bovis bacillus Calmette–Guérin (BCG), which has been used in newborns for many decades and in several countries as a tuberculosis vaccine. We have previously shown that immunization with BCG strains expressing hRSV Ags can induce an efficient immune response that protects against this virus. In this study, we show that immunization with rBCG strains expressing the phosphoprotein from hMPV also can induce protective Th1 immunity. Mice immunized with rBCG were protected against weight loss, airway inflammation, and viral replication in the lungs after hMPV infection. Our rBCG vaccine also induced the activation of hMPV-specific T cells producing IFN-γ and IL-2, which could protect from hMPV infection when transferred to recipient mice. These data strongly support the notion that rBCG induces protective Th1 immunity and could be considered as an efficient vaccine against hMPV.

Section: Lung Histopathology and Immunofluorescence Assaysmentioning

confidence: 99%

Immunization with a Recombinant Bacillus Calmette–Guérin Strain Confers Protective Th1 Immunity against the Human Metapneumovirus

Palavecino

Céspedes

Gómez

et al. 2014

“…Slices of 7 mm were obtained by using a Leica CM1510S cryostat (Leica Microsystems, Deerfield, IL) and stained either with H&E or phenol red for eosinophil detection, as previously described (26). For detection of apoptotic cells, a DeadEnd Fluorometric TUNEL System (Promega, Madison, WI) was used according to the manufacturer's recommendation.…”

Section: Lung Histopathology and Immunofluorescence Assaysmentioning

confidence: 99%

Efficient Lung Recruitment of Respiratory Syncytial Virus-Specific Th1 Cells Induced by Recombinant Bacillus Calmette-Guérin Promotes Virus Clearance and Protects from Infection

Cautivo

Bueno

Cortés

et al. 2010

“…Sections were stained with H&E using standard methods. For the detection of eosinophils by fluorescence microscopy, phenol red staining was also performed on some sections, as described (28). The specificity for eosinophils of phenol red staining was confirmed by observing abrogation of fluorescence after treatment with resorcinol (200 M), an inhibitor of eosinophil peroxidase activity (29).…”

Section: Histological Analysismentioning

confidence: 99%

IFN-α/β Signaling Is Required for Polarization of Cytokine Responses toward a Protective Type 1 Pattern during Experimental Cryptococcosis

Biondo

Midiri

Gambuzza

et al. 2008

The antiviral activities of type I IFNs have long been established. However, comparatively little is known of their role in defenses against nonviral pathogens. We examined here the effects of type I IFNs on host resistance against the model pathogenic yeast Cryptococcus neoformans. After intratracheal or i.v. challenge with this fungus, most mice lacking either the IFN-α/β receptor (IFN-α/βR) or IFN-β died from unrestrained pneumonia and encephalitis, while all wild-type controls survived. The pulmonary immune response of IFN-α/βR−/− mice was characterized by increased expression of IL-4, IL-13, and IL-10, decreased expression of TNF-α, IFN-γ, inducible NO synthetase, and CXCL10, and similar levels of IL-12 mRNA, compared with wild-type controls. Histopathological analysis showed eosinophilic infiltrates in the lungs of IFN-α/βR−/− mice, although this change was less extensive than that observed in similarly infected IFN-γR-deficient animals. Type I IFN responses could not be detected in the lung after intratracheal challenge. However, small, but statistically significant, elevations in IFN-β levels were measured in the supernatants of bone marrow-derived macrophages or dendritic cells infected with C. neoformans. Our data demonstrate that type I IFN signaling is required for polarization of cytokine responses toward a protective type I pattern during cryptococcal infection.