Antibodies to human gastric epithelial cells and heat shock protein 60 in Helicobacter pylori positive mucosa associated lymphoid tissue lymphoma

Abstract

Background: Development of gastric mucosa associated lymphoid tissue (MALT) lymphoma is thought to be closely associated with host immune reactions to Helicobacter pylori.

Aim: To investigate humoral immune responses in patients with MALT lymphoma to antigens shared by H pylori and human gastric epithelial cells.

Methods: Sera were obtained from H pylori positive patients with MALT lymphoma (n = 11) or other gastroduodenal diseases (peptic ulcer, n = 40; non-ulcer dyspepsia, n = 20) and from H pylori negative healthy control subjects (n = 10). Antibodies to HGC-27 human gastric epithelial cells and human recombinant heat shock protein (Hsp) 60 were examined using an enzyme linked immunosorbent assay (ELISA) and immunoblotting.

Results: Antibody titres to HGC-27 cells were significantly elevated in H pylori positive patients with MALT lymphoma when compared with titres in patients with other gastroduodenal diseases and in healthy subjects. Immunoblotting of sera from patients with MALT lymphoma often detected a band with a molecular mass corresponding to Hsp60, and both ELISA and immunoblotting showed elevated antibody titres to the recombinant human Hsp60. Antigenic similarity between Hsp60 and H pylori HspB was documented by immunoblotting experiments.

Conclusions: Autoantibodies reactive with host gastric epithelial cells are often increased in MALT lymphoma, and Hsp60 is a major target antigen. Immune responses induced by immunological cross reactivity between H pylori HspB and human Hsp60 in gastric epithelium may be involved in the development of MALT lymphoma.

Figure 1

Serum antibody titres to HGC-27 cells in patients with mucosa associated lymphoid tissue mucosa associated lymphoid tissue (MALT) lymphoma, gastric ulcer, duodenal ulcer, or non-ulcer dyspepsia, and control healthy subjects. Serum antibodies to HGC-27 human gastric epithelial cells were measured using cell ELISA with plates seeded with HGC-27 cells. ***p<0.001 (Student's t test).

Figure 2

Immunoblots of HGC-27 cells allowed to react with serum from various patient and control groups. Lysates of HGC-27 cells were fractionated on 10% polyacrylamide gels and then immunoblotted. (A) Lane A, The membrane strip was allowed to react with LK-2 mouse monoclonal antibody to human Hsp60. Lanes 1-7, the strips were allowed to react with serum from patients with mucosa associated lymphoid tissue (MALT) lymphoma. Bands with an approximate molecular mass of 60 kDa which correspond to Hsp60 are indicated by an arrow. (B) The membrane strip was allowed to react with serum from patients with non-ulcer dyspepsia (lanes 1-3), gastric ulcer (lanes 4-6), or duodenal ulcer (lanes 7 and 8), and from a healthy control subject (lane 9). Lane A, LK-2.

Figure 3

Immunoblots of recombinant human Hsp60 allowed to react with sera from patients with mucosa associated lymphoid tissue (MALT) lymphoma. Recombinant human Hsp60 proteins were fractionated on 10% polyacrylamide gels and then immunoblotted. Lane A, the membrane strip was allowed to react with LK-2 mouse monoclonal antibody to human Hsp60. Lanes 1-11, the strips were allowed to react with sera from patients with MALT lymphoma. Bands with approximate molecular mass 60 kDa, which correspond to Hsp60, are present in lanes 1-10 (arrow).

Figure 4

Serum antibody titres to recombinant human Hsp60 in patients with mucosa associated lymphoid tissue (MALT) lymphoma, gastric ulcer, duodenal ulcer, or non-ulcer dyspepsia, and control healthy subjects. Serum antibodies to human Hsp60 were measured using ELISA with plates coated with recombinant human Hsp60. *p<0.001 (Student's t test).

Figure 5

Immunoblots with LK-2 mouse monoclonal antibody to human Hsp60. Recombinant human HSP60 (lane A), lysates of HGC-27 cells (lane B), and sonicates of H pylori (lane C) were fractionated on 10% polyacrylamide gels and then immunoblotted. The membrane strip was allowed to react with LK-2 mouse monoclonal antibody to human Hsp60. Bands with approximate molecular mass 60 kDa (Hsp60 in lane A) are also present in lanes B and C.