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The microbiological, histological, immunological and molecular determinants of Helicobacter pylori infection in guinea pigs as a convenient animal model to study pathogenicity of these bacteria and the infection dependent immune response of the host

100%

Walencka M., Gonciarz W., Mnich E., Gajewski A., Stawerski P., Knapik-Dabrowicz A., Chmiela M.

2015

vol. 62

issue 4

697-706

Helicobacter pylori is an etiological agent of chronic gastritis, gastric and duodenal ulcers and gastric cancers. The use of an appropriate animal model for experimental studies on the pathogenesis of H. pylori infections is necessary due to the chronic character of such infections and difficulties in identifying their early stage in humans. The aim of this study was to develop a guinea pig model of H. pylori infection and identify its microbiological, histological, serological and molecular determinants. Guinea pigs were inoculated per os with H. pylori strains: CCUG 17874 or ATCC 700312, both producing vacuolating cytotoxin A (VacA) and cytotoxin associated gene A (CagA) protein, suspended in Brucella broth with fetal calf serum (FCS) and Skirrow supplement of antibiotics. To determine H. pylori colonization, 7 and 28 days after the challenge, a panel of diagnostic methods was used. It included culturing of microorganisms from the gastric tissue, histopathological analysis of gastric sections, stained by Mayer,s haematoxylin and eosin to assess inflammatory response, by Giemsa as well as Warthin-Starry silver staining to visualise Helicobacter-like organisms (HLO) and with anti-Ki-67 antigen to assess epithelial cell proliferation. H. pylori infection was also confirmed by polymerase chain reactions (PCR) for detection in gastric tissue of ureC and cagA genes and by serological assessment of H. pylori antigens in faeces. This study showed the usefulness of microbiological, histological, immunological and molecular methods for the detection of persistent H. pylori infections in guinea pigs, which could be an appropriate model for studying H. pylori pathogenesis and the related immune response against these microbes.

Immunoregulation of antigen presenting and secretory functions of monocytic cells by Helicobacter pylori antigens in relation to impairment of lymphocyte expansion

84%

Mnich E., Gajewski A., Rudnicka K., Gonciarz W., Stawerski P., Hinc K., Obuchowski M., Chmiela M.

2015

vol. 62

issue 4

641-650

The role of Helicobacter pylori (H. pylori) antigens in driving a specific immune response against the bacteria causing gastroduodenal disorders is poorly understood. Using a guinea pig model mimicking the natural history of H. pylori infection, we evaluated the effectiveness of immature and mature macrophages in promoting the blastogenesis of splenocytes from H. pylori infected and uninfected animals, in response to H. pylori antigens: glycine acid extract (GE), cytotoxin associated gene A protein (CagA), urease A (UreA) and lipopolysaccharide (LPS). Lymphocyte expansion was assessed in 72 h cell cultures, containing: immature or mature macrophages derived from bone marrow monocytes, unstimulated or stimulated with H. pylori antigens for 2 h. The proliferation was expressed as a ratio of [3H]-thymidine incorporation into DNA of antigen-stimulated to unstimulated cells and the DNA damage was determined by DAPI cell staining. TGF-β and IFN-γ were assessed immunoenzymatically in cell culture supernatants. Lymphocytes of control and H. pylori-infected animals proliferated intensively in response to phytohaemagglutinin (PHA) and in co-cultures with immature or mature macrophages treated with CagA or UreA (significantly) and GE (slightly) exluding the cultures containing H. pylori or E. coli LPS. This lymphocyte growth inhibition was related to DNA damage of monocytic cells in response to H. pylori or E. coli LPS and secretion of regulatory TGF-β, but not proinflammatory IFN-γ. Impaired homeostasis of monocytic cell function related to DNA damage and TGF-β release, in response to H. pylori LPS may lead to the suppression of adaptive immune response against the bacteria and development of chronic infection.

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2 Acta Biochimica Polonica

2 2015

2 Chmiela M.

2 Gajewski A.

2 Gonciarz W.

2 Mnich E.

2 Stawerski P.

1 Hinc K.

1 Knapik-Dabrowicz A.

1 Obuchowski M.

1 Rudnicka K.

1 Walencka M.

Search results

The microbiological, histological, immunological and molecular determinants of Helicobacter pylori infection in guinea pigs as a convenient animal model to study pathogenicity of these bacteria and the infection dependent immune response of the host

Immunoregulation of antigen presenting and secretory functions of monocytic cells by Helicobacter pylori antigens in relation to impairment of lymphocyte expansion