Intestinal helminth infection enhances bacteria-induced recruitment of neutrophils to the airspace

Shao Rong Long,Bernard B Lanter,Michael A Pazos,Hongmei Mou,Juliana Barrios,Chien-Wen Su,Zhong Quan Wang,W Allan Walker,Bryan P Hurley,Hai Ning Shi

doi:10.1038/s41598-019-51991-3

Shao Rong Long, Bernard B Lanter + Show 8 more

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https://doi.org/10.1038/s41598-019-51991-3

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Intestinal helminth infections elicit Th2-type immunity, which influences host immune responses to additional threats, such as allergens, metabolic disease, and other pathogens. Th2 immunity involves a shift of the CD4+ T-cell population from type-0 to type-2 (Th2) with increased abundance of interleukin (IL)-4 and IL-13. This study sought to investigate if existing gut-restricted intestinal helminth infections impact bacterial-induced acute airway neutrophil recruitment. C57BL/6 mice were divided into four groups: uninfected; helminth-Heligmosomoides polygyrus infected; Pseudomonas aeruginosa infected; and coinfected. Mice infected with H. polygyrus were incubated for 2 weeks, followed by P. aeruginosa intranasal inoculation. Bronchial alveolar lavage, blood, and lung samples were analyzed. Interestingly, infection with gut-restricted helminths resulted in immunological and structural changes in the lung. These changes include increased lung CD4+ T cells, increased Th2 cytokine expression, and airway goblet cell hyperplasia. Furthermore, coinfected mice exhibited significantly more airspace neutrophil infiltration at 6 hours following P. aeruginosa infection and exhibited an improved rate of survival compared with bacterial infected alone. These results suggest that chronic helminth infection of the intestines can influence and enhance acute airway neutrophil responses to P. aeruginosa infection.

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Intestinal helminth infections elicit Th2-type immunity, which influences host immune responses to additional threats, such as allergens, metabolic disease, and other pathogens
The total number of cells was increased significantly further in bronchial alveolar lavage (BAL) fluid collected from mice coinfected with helminth and P. aeruginosa, compared to that detected in mice infected with P. aeruginosa alone (Fig. 1a)
Our results show that H. polygyrus coinfection significantly increased survival rate of infected hosts, which corresponds with a trend showing decreased bacterial dissemination into the spleen, when compared to P. aeruginosa infection alone (Fig. 1c,d)

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Intestinal helminth infections elicit Th2-type immunity, which influences host immune responses to additional threats, such as allergens, metabolic disease, and other pathogens. Given pervasive co-infection of respiratory pathogens and intestinal helminths in children from low and middle income countries as well as the complex influence that helminth infection can exert on host immunity, an in vivo coinfection model was developed to investigate possible influences of chronic helminth infection on bacteria-induced airway inflammation. This investigation sought to determine if a chronic gut-restricted H. polygyrus infection in mice influenced the early innate immune response within the murine lung challenged with the respiratory pathogen Pseudomonas aeruginosa. Neutrophil recruitment into the airspace is an important feature of acute bacterial pneumonia and these studies as well as the novel model developed, represent a useful approach to investigate a possible interrelationship between intestinal parasitic infection and bacterial pneumonia

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