IgG Subclasses Against Helicobacter pylori Isolates: An important Tool for Disease Characterization

Abstract

Helicobacter pylori infects around 50% of the world’s population and is associated with diverse pathologies. In the most severe cases, the bacterium causes peptic ulcers and gastric cancer. The interplay between H. pylori and the host’s immune response may help to determine the specific outcome of the infection. To study the relationship between antibody subclasses and variation in immune recognition, we determined the immunoglobulin G1 and 2 (IgG1 and IgG2) titres of sera obtained from patients with different H. pylori‐associated pathologies. IgG1 and IgG2 titres were determined by ELISA in 44 sera of patients with different H. pylori‐associated diseases (peptic ulcer, bleeding peptic ulcers, gastric cancer and dyspepsia). Soluble proteins from lysates were obtained from 12 different clinical isolates from similar associated diseases. We found that soluble proteins from lysates of H. pylori strains (SPLHP) recognition patterns in these sera were highly variable. Overall, IgG2 titres were higher than the IgG1 titres in the infected patients. In particular, those with peptic ulcers showed marked elevation in IgG2/IgG1 ratios, while SPLHPs from dyspeptic patients resulted in high IgG1 titres. Our results reveal that correlation of antibody subclass titres with Th1/Th2 markers may aid pathology characterization and show a potential diagnosis that could be formally evaluated in other studies.

Activation of CD3+ T cells by Helicobacter pylori DNA vaccines in potential immunotherapy of gastric carcinoma

“…21 Thus, DNA vaccination induces a shift from the Th1 to Th2 responses that fundamentally mimic the changing immune status in the host of GC with chronic H. pylori infection. 21,45 The elevated TNF-α level is identified after vaccination to mimic the changes in the TNF-α expression induced by H. pylori infection in patients with chronic gastritis, intestinal metaplasia, dysplasia and GC. 46 In addition, the H. pylori DNA vaccines stimulate significant proliferation of both peripheral CD3 + CD4 + and CD3 + CD8 + T cells in mice and the enhanced proliferation and effector roles of activated CD3 + T cells are thought to likely inhibit tumor growth and improve prognosis of Hp-GC.…”

Gastric cancer progression associated with local humoral immune responses

“…The plates were then read using a microplate reader (GENios Plus, Tecan Austria GmbH, Grödig, Austria). The antibody titer was calculated by plotting luminescence versus serum dilution; the luminescence value was 1 above the background while the data were analysed by calculating the log10 of the titre dilution as described by Martinez-Becerra et al, [ 19 ].…”

Association of host immunity with Helicobacter pylori infection in recurrent gastric cancer

“…In the context of anti- H. pylori immunity, studies on serum anti -H. pylori IgG subclass have indicated that subjects with low levels of IgG2 anti- H. pylori antibody were at a risk of gastric cancer [13, 14], suggesting that a decreasing Th1 response is associated with developing gastric cancer. IL-10 inhibits the production of pro-inflammatory cytokines by inhibition of Th1 lymphocytes, and stimulation of B lymphocytes and Th2 lymphocytes and thus downregulates the inflammatory response [15–17].…”