Natural IgM and IgG antibodies to Thomsen-Friedenreich (T) antigen in serum of patients with gastric cancer and blood donors--relation to Lewis (a,b) histo-blood group phenotype.

A possible association of serum anti-T IgM and IgG antibody levels with Lewis blood-group phenotype was investigated in 168 blood donors and 132 gastric cancer patients using ELISA with synthetic T-disaccharide-polyacrylamide conjugate as antigen. The donors of Le(a-b+) phenotype showed the highest anti-T IgM level irrespective of ABO(H) blood group. A significant decrease in anti-T IgM in serum was observed among cancer patients of Le(a-b+) phenotype: 95% of weak responders versus 17.5% for related groups of donors (p < 10(-6)). In contrast, no significant difference between patients and donors was found for Le(b-) individuals. Thus, a level of natural anti-T antibodies in serum of blood donors and its decrease in patients with gastric cancer are related to Le(a,b) phenotype. This should be taken into account where anti-T antibody level in the serum is used as a tumour marker or for monitoring patients during cancer immunotherapy with mucin-type vaccines.

IgG antibodies to Lewis type 2 antigens in serum of H. pylori-infected and noninfected blood donors of different Lewis(a,b) blood-group phenotype.

Individuals of the Le(b+)/secretor phenotype revealed a stronger natural immune response to Le(x) and Le(y) epitopes irrespective of Helicobacter pylori serologic status. In contrast, H. pylori-infected Le(b-) type individuals showed a significantly higher proportion of strong responders to Le(x) antigen compared with the H. pylori-uninfected subgroup. The data suggest that the immune response to Lewis type 2 determinants is related to both the H. pylori serologic status and the Le(a,b) phenotype of the host.

The Helicobacter pylori seroprevalence in blood donors related to Lewis (a,b) histo-blood group phenotype.

OBJECTIVE: To study a possible association of the Helicobacter pylori seroprevalence with ABO(H) and Lewis (a,b) blood group phenotypes in blood donors. DESIGN: A cross-sectional study of blood donors using ABO(H) and Lewis (a,b) blood group phenotype as predictors. METHODS: ABO(H) and Lewis (a,b) blood group phenotyping was performed with monoclonal antibody. The H. pylori immunoglobulin G (IgG) antibody relative activity was evaluated by enzyme-linked immunosorbent assay (ELISA) using acid glycine extract from H. pylori. SUBJECTS: One hundred and fifty-nine randomly selected blood transfusion donors. RESULTS: The individuals with Lewis (a+b-)/non-secretor phenotype showed a significantly higher proportion of the H. pylori-seronegative subjects and a lower IgG immune response to H. pylori antigens as compared with the individuals of Lewis (a-b+)/secretor phenotype. CONCLUSION: The Lewis (a,b) histo-blood group antigens are implicated in the mechanisms of naturally occurring resistance to H. pylori infection.

[The induction and disappearance of complement-fixing antibodies in the blood serum of experimental animals under the antigenic action of Trichomonas vaginalis, T. hominis and T. tenax]. / Vozniknovenie i ischeznovenie komplementsviazyvaiushchikh antitel v syvorotke krovi podopytnykh zhivotnykh pod deistviem antigenov Trichomonas vaginalis, T. hominis i T. tenax.

For studying the dynamics of induction and disappearing of complement-fixing antibodies (CFA) specific to Trichomonas vaginalis, T. hominis and T. tenax we have immunized rabbits intravenously with live individuals of the protozoa as well as intravenously, intramuscularly and subcutaneously with individuals killed at 56 degrees C. Each method of immunization was carried out by 5 inoculations with intervals of 10 days. For carrying out quantitative complement fixation we have taken blood from the ear vein of all immunized rabbits immediately before the immunization and also after it, each 10th day during one year. The dynamics of rising and lowering of titres depended on the species of trichomonads and on the method of immunization. The antigens of T. vaginalis and T. hominis induced CFA in much higher titres as antigens of T. tenax. Titres of CFA specific for all three species of above-mentioned trichomonads rose most rapidly and to the highest level when the immunization of rabbits was carried out intravenously with live individuals of protozoa. Normalization of the titres of CFA has taken place during one year at least.