Priming with high and low respiratory allergen dose induces differential CD4+ T helper type 2 cells and IgE/IgG1 antibody responses in mice

Early IgE Production Is Linked with Extrafollicular B- and T-Cell Activation in Low-Dose Allergy Model

Despite its paramount importance, the predominant association of early IgE production with harmless antigens, via germinal-center B- and T-cell subpopulations or extrafollicular activation, remains unresolved. The aim of this work was to clarify whether the reinforced IgE production following the subcutaneous immunization of BALB/c mice with low antigen doses in withers adipose tissue might be linked with intensified extrafollicular or germinal-center responses. The mice were immunized three times a week for 4 weeks in the withers region, which is enriched in subcutaneous fat and tissue-associated B cells, with high and low OVA doses and via the intraperitoneal route for comparison. During long-term immunization with both low and high antigen doses in the withers region, but not via the intraperitoneal route, we observed a significant accumulation of B220-CD1d-CD5-CD19+ B-2 extrafollicular plasmablasts in the subcutaneous fat and regional lymph nodes but not in the intraperitoneal fat. Only low antigen doses induced a significant accumulation of CXCR4+ CXCR5- CD4+ extrafollicular T helpers in the withers adipose tissue but not in the regional lymph nodes or abdominal fat. Only in subcutaneous fat was there a combination of extrafollicular helper accumulation. In conclusion, extrafollicular B- and T-cell activation are necessary for early IgE class switching.

Mimicking Antigen-Driven Asthma in Rodent Models-How Close Can We Get?

Asthma is a heterogeneous disease with increasing prevalence worldwide characterized by chronic airway inflammation, increased mucus secretion and bronchial hyperresponsiveness. The phenotypic heterogeneity among asthmatic patients is accompanied by different endotypes, mainly Type 2 or non-Type 2. To investigate the pathomechanism of this complex disease many animal models have been developed, each trying to mimic specific aspects of the human disease. Rodents have classically been employed in animal models of asthma. The present review provides an overview of currently used Type 2 vs. non-Type 2 rodent asthma models, both acute and chronic. It further assesses the methods used to simulate disease development and exacerbations as well as to quantify allergic airway inflammation, including lung physiologic, cellular and molecular immunologic responses. Furthermore, the employment of genetically modified animals, which provide an in-depth understanding of the role of a variety of molecules, signaling pathways and receptors implicated in the development of this disease as well as humanized models of allergic inflammation, which have been recently developed to overcome differences between the rodent and human immune systems, are discussed. Nevertheless, differences between mice and humans should be carefully considered and limits of extrapolation should be wisely taken into account when translating experimental results into clinical use.

Total and double-stranded DNA-specific immunoglobulin E in bronchoalveolar lavage fluid of children with human adenovirus pneumonia

BACKGROUND

Some antibodies and autoreactive antibodies are associated with the severity of infectious diseases. The roles of humoral responses to lung inflammation in children with human adenovirus (HAdVs) pneumonia remain unknown.

PATIENTS AND METHODS

A retrospective study was done to compare plasma immunoglobulin E (IgE) levels between HAdVs pneumonia patients and healthy children by searching the electronic medical record system of Guangzhou Women and Children's Medical Center. Then, a prospective study was performed for children with HAdVs pneumonia who needed flexible bronchoscopy for examination and treatment purposes during July 2017 to July 2019. We examined the IgE and autoreactive IgE levels in plasma and bronchoalveolar lavage fluid (BALF) of these children to explore their role in HAdVs pneumonia.

RESULTS

A significantly higher level of IgE was found in plasma from children hospitalized with HAdVs pneumonia compared with that from healthy children in the same age range. Furthermore, the levels of IgE, double-stranded DNA (dsDNA), and double-stranded DNA-specific immunoglobulin E (dsDNA-IgE) in BALF were increased compared to plasma in children with HAdVs pneumonia. The levels of IgE, dsDNA, and dsDNA-IgE in BALF were significantly higher in the severe group compared to the non-severe group. The ability of IgE in BALF to recognize dsDNA was verified by the ELISPOT test.

CONCLUSIONS

Our findings indicate that IgE and dsDNA-IgE in BALF may contribute to lung injury caused by HAdVs, especially in severe cases. Elevated dsDNA-IgE may serve as an indicator of severity in children with HAdVs pneumonia.

Effect of neuromedin U on allergic airway inflammation in an asthma model

Asthma is a major inflammatory airway disease with high incidence and mortality rates. The Global Initiative for Asthma released a report called ‘The Global Burden of Asthma’ in 2004. However, the specific pathogenesis of asthma remains unclear. An increasing number of studies have demonstrated that neuromedin U (NMU) plays a pleiotropic role in the pathogenesis of asthma. NMU is a highly structurally conserved neuropeptide that was first purified from porcine spinal cord and named for its contractile effect on the rat uterus. NMU amplifies type 2 innate lymphoid cell (ILC2)-driven allergic lung inflammation. The NMU receptors (NMURs), designated as NMUR1 and NMUR2, belong to the G protein-coupled receptor family. NMUR1 has also been found in immune cells, including ILC2s, mast cells and eosinophils. In view of the important roles of NMU in the pathogenesis of asthma, the present review evaluates the potential mechanisms underlying the impact of NMU on asthma and its association with asthma therapy.