title: Escherichia coli shares T- and B-lymphocyte epitopes with Schistosoma mansoni.
abstract: BACKGROUND
  In this study, we tested the cross-reaction between crude Escherichia coli antigen (ECA) and 3 crude Schistosoma mansoni antigens.
  
  
  METHODS
  The schistosomal antigens used were cercarial antigen preparation (CAP), soluble worm antigen preparation (SWAP), and soluble egg antigen (SEA). Four groups each of 3 mice received 2 intraperotineal immunizations with the above-mentioned antigens at a two-week interval. The dose of the ECA was 20 microg/100 microl PBS/mouse and that of any of the used schistosomal antigens was 50 microg/100 microl PBS/mouse. IgM and IgG reactivities and cross-reactivities were tested in individual immunized mice sera (IMS) against the above-mentioned antigens by ELISA and Western blotting. The changes in the B, CD4+ and CD8+ -T cells' counts post immunization were recorded.
  
  
  RESULTS
  Priming with ECA caused significant increases in IgM (P<0.05) against CAP and SWAP, while both priming and boosting with ECA caused a significant elevation in the IgG only against SWAP. Priming and boosting with ECA or schistosomal antigens caused significant increases in IgM against ECA. Priming with ECA or SWAP caused significant elevation in IgG against ECA. In Western blotting, ECA-IMS recognized 16, 33, 38 and 94 kDa ECA peptides that cross-reacted with CAP-IMS. ECA peptides at 30 and 38 kDa cross-reacted among ECA, SWAP and SEA-IMS. CAP peptides at 40, 71, 85 and 97 kDa cross-reacted with ECA-IMS. A 59 kDa SWAP peptide cross-reacted with ECA. SEA peptides at approximately 55, 96 and 101 kDa cross-reacted with ECA-IMS. Immunization with ECA, CAP, SWAP or SEA caused significant increases in mesentric lymph nodes (MLN)-CD4+, CD8+ -T cells and MLN-B cells. For thymocytes, CD4+ -T cells significantly increased upon immunization with ECA and SWAP while CD8+-T cells significantly increased upon immunization with SWAP.
  
  
  CONCLUSIONS
  It is necessary to include E. coli antigens as controls while establishing schistosomal antigens-based diagnostic tests to ensure the specificity of the detected immune responses. Characterization of the cross-reactive ECA antigens with protective potential against S. mansoni infection remains a future research objective.
authors.affiliation: Therapeutical Chemistry Department, Immunology and Infectious Diseases Laboratory, the Center of Excellence for Advanced Sciences, the National Research Center Dokki, Cairo 12311, Egypt. mbahgatriad@yahoo.com
authors.forename: Mahmoud Mohamed
authors.initials: MM
authors.lastname: Bahgat
authors.forename: Hanaa Mohamed
authors.initials: HM
authors.lastname: Gaber
authors.forename: Amany Sayed
authors.initials: AS
authors.lastname: Maghraby
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D000909:Antibodies, Helminth / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology; D000947:Antigens, Helminth / Q000276:immunology; D015153:Blotting, Western / Q000379:methods; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D004926:Escherichia coli / Q000276:immunology*; D005260:Female; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D018655:Lymphocyte Count; D051379:Mice; D012550:Schistosoma mansoni / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000909:Antibodies, Helminth; D000942:Antigens, Bacterial; D000947:Antigens, Helminth; D018985:Epitopes, B-Lymphocyte; D018984:Epitopes, T-Lymphocyte; D007074:Immunoglobulin G; D007075:Immunoglobulin M