Inhibition by lipoid A of formation of antibodies against common antigen of enterobacteriaceae

Immune responses to hapten-lipopolysaccharide conjugates in mice. III. Genetics of the antibody response to polysaccharide antigens

Antibody responses to the polysaccharide antigens of bacterial lipopolysaccharides and their hapten derivatives are herein documented to be under multigenic control. Among the genes responsible for the antibody response to these polysaccharide antigens include those coded for by genes located on the X chromosome and those on chromosome 17 linked to genes in the H-2 and/or Qa loci. The use of B10 congenic mice revealed that two genes on chromosome 17 are involved in the regulation of the antibody response to bacterial polysaccharide antigens. The use of CXB recombinant inbred mice confirmed the multigenic control of the antibody response within their background array of genes. The data clearly demonstrate that immune responses to these polysaccharide antigens are under genetic control, the importance of which may be of significance with regard to humoral protection during gram-negative infection.

Immunological activities of purified preparations of enterobacterial common antigen

The immunological activities of three purified preparations of enterobacterial common antigen (ECA) obtained by different procedures were studied. ECA-Ma (method of A. Marx) was from Salmonella typhimurium TV149 (Ra mutant), ECA-My (method of H. Mayer) was from S. montevideo, and ECA-Ro (method of E. Romanowska) was from Shigella sonnei phase I. These preparations, on a weight basis, neutralized similar amounts of ECA antibodies, indicating that the serological activities were comparable. Neither ECA-My nor ECA-Ro elicited specific delayed-type hypersensitivity skin reactions at 24 or 48 h in immunized guinea pigs. ECA-Ma, as well as the nonpurified preparations of the antigens used for immunization, elicited reactions at 24 h but not at 48 h. Thus, ECA-specific delayed-type hypersensitivity was not detected in immunized guinea pigs. Striking differences were noted in the immunogenicity of these antigens, ECA-Ma being highly immunogenic in the rabbit in contrast to ECA-My and ECA-Ro. ECA-Ma was a potent mitogen for guinea pig spleen cells, stimulating high levels of DNA synthesis; ECA-My was only slightly active. The three antigens were mitogenic to spleen cells from both CBA/J and C3H/HeJ mice, although not to the same degree, indicating that this effect is not due to contaminating lipopolysaccharide, since the latter strain of mice is resistant to endotoxin. Since an ECA-Ma extract made from an ECA-negative mutant proved to be mitogenic to murine spleen cells, the mitogenicity is not due to the ECA haptenic determinant. The mitogenic effect is polyclonal in nature, ECA-Ma producing a maximum response on day 3. Thus, the ECA preparations are both B-cell mitogens and polyclonal activators in murine spleen cells. From these studies it is evident that the biological and immunological activities of these purified antigens depend not only on the haptenic determinant but also on associated or bound components of the preparations.

Common enterobacterial antigen in Yersinia enterocolitica

Production of the common enterobacterial antigen (CA) by strains of Yersinia enterocolitica (Y.e.) serotypes 3 and 9 (Winblad), by strains of 5 different Y.e. serogroups (Wauters) and various other bacteria was examined. Antibody against CA was raised by immunization of rabbits with E. coli O 14. Extract prepared from S. typhimurium was used for the sensitization of sheep erythrocytes with CA. Absorption and haemagglutination inhibition experiments showed that CA could be detected in heat extracts from all Y.e. strains examined, and in that from Yersinia pseudotuberculosis. CA was not detected in extracts from Pasteurella multocida, Francisella tularensis, Brucella abortus, Acinetobacter calcoaceticus or Pseudomonas aeruginosa. Anti-CA antibodies could not be demonstrated in serum from rabbits immunized with Y.e. bacteria, but were demonstrated in serum from rabbits immunized with a CA-containing fraction of the Y.e. extract. The possibility of participation of anti-CA antibody in indirect haemagglutination tests for detection of antibody to Y.e. O antigens is emphasized.

Immunochemistry of the common antigen of Enterobacteriaceae (Kunin). Relation to lipopolysaccharide core structure

Preparations of E. coli 014 lipopolysaccharide (LPS) contain a common enterobacterial antigen (CA) in large amounts or in an immunogenic form. Chemical analysis revealed, in addition to o-acetyl groups, only those sugars which are present in the basal core structure of the E. coli or Salmonella LPS (e.g., galactose, glucose, glucosamine, heptose, and ketodeoxyoctonate). On treatment with acetic acid (pH 3.2) at 100 degrees C for 1.5 hr, a fragment was liberated which after gel filtration on Sephadex G-50 appeared in the molecular weight range of 2-3 x 10(3). The fragment inhibited precipitation of alkali-treated E. coli 014 LPS by antibodies to CA from anti-E. coli 014 serum. It also inhibited hemagglutination between anti-CA antibodies and red cells coated with E. coli 08 LPS. Chemical analysis of the fragment indicated that it corresponded to the core region of E. coli 014 LPS. It contained a heptose and ketodeoxyoctonate in addition to glucose and galactose. However the fraction lacked glucosamine. Enterobacterial CA has previously been found to cross-react with colon antigen of ulcerative colitis. These results should provide a chemical basis for further studies of this cross-reactivity.

Prevention of Experimental Hematogenous and Retrograde Pyelonephritis by Antibodies Against Enterobacterial Common Antigen

Rabbits were immunized with common antigen (CA) derived from Salmonella typhimurium . Animals with CA hemagglutinin titers of 1-320 to 1-81,920 were injected with 10 7 viable Proteus mirabilis via the retrograde and hematogenous routes. Nonimmune control groups were challenged similarly. From the retrogradely challenged groups sacrificed at 4 weeks, pyelonephritis was found in 89% of the control animals but not in those immunized. Bacteriuria was present in 89% of the controls but in only 61% of the immunized group. Hematogenously challenged, immune animals sacrificed at 6 weeks did not show histological evidence of renal pathology, and only 6% had bacteriuria. Eighty-six per cent of the nonimmune controls showed both pyelonephritis and bacteriuria. The protective effect is specific because of the following. (i) Active and passive CA immunization did not prevent pyelonephritis due to Pseudomonas aeruginosa which does not produce this antigen. (ii) Passive immunization with a CA antiserum conferred protection against a P. mirabilis challenge. (iii) Passive administration of an antiserum from which CA antibodies had been differentially absorbed abolished the protective activity.

Chlorphenesin: an Antigen-Associated Immunosuppressant

Chlorphenesin (3- p -chlorophenoxy-1,2-propanediol), when injected intravenously together with either of two common bacterial antigens, inhibits the antibody response of the rabbit. The antigens studied are those common to Enterobacteriaceae and to gram-positive bacteria. The immunosuppression is contingent upon incubation of chlorphenesin and antigen in vitro prior to administration, since separate injection of antigen and inhibitor or of mixtures without prior incubation yields undiminished antibody response. Chlorphenesin, as shown by hemagglutination-inhibition tests, does not alter the antigenic determinants, because antibody neutralization occurs in the presence or absence of the drug. The immunosuppressive effect is reversible, since precipitation of chlorphenesin at 4 C substantially restores immunogenicity. Animals immunized with antigen-drug mixtures, which fail to respond with significant antibody production, nonetheless are immunologically primed. It is concluded that chlorphenesin represents another example of antigen-associated immunosuppressants.

Immunological studies in ulcerative colitis. IV. Origin of autoantibodies

The incidence and height of antibody titers to colon, assayed by indirect hemagglutination with a heat stable colon extract from germ free rats, is significantly higher in sera from patients with ulcerative colitis than in those from healthy controls or from patients with amebic liver abscess or dysentery. While sera from ulcerative colitis patients and controls are indistinguishable in regard to incidence and height of antibody titers to Forsman antigen, Staphylococcus aureus S 209, Clostridium difficile, and several common strains of E. coli, they have elevated titers and increased incidence of antibodies to a heat stable antigen of E. coli O14. Patients with amebic dysentery have normal titers of such antibodies. Absorption of patients' sera with E. coli O14 antigen inhibits the colon directed hemagglutination reaction in approximately 30% of the cases tested. Likewise, the anti-E. coli O14 reaction can sometimes be inhibited with the colon extract. Other E. coli strains and other bacteria are inactive or have only weak inhibitory activity. Hemagglutination inhibition experiments show that germ free rat colon and E. coli O14 contain common structures, depicted by antibodies in the patients' sera. This pattern of reactivity closely resembles that seen in rats made autoimmune to colon by injection of newborn rabbit colon. E. coli O14 is known to carry a heterogenetic antigen present in lower concentration (or activity) in most Enterobacteriaceae. Hemagglutination inhibition experiments with rabbit antisera to E. coli O14 suggest that the antigen common for E. coli O14 and colon is related to this heterogenetic antigen. The findings imply that this antigen, which is constantly present in low concentrations in the human colon, may give rise to anticolon antibody formation in ulcerative colitis through breakage of tolerance. Since this antigen is present in healthy individuals as well, additional factors are required to explain the induction of anti-colon autoimmunity in ulcerative colitis.