Publisher Summary This chapter discusses the principles and procedures for serotyping of Escherichia coli (E. coli) and discusses the morphology and immunochemistry of the surface structures that are important in serotyping. The genus Escherichia is one of the genera of tribus Escherichieae as defined in Bergey's Manual of Determinative Bacteriology. It contains one species E. coli, which consists of Gram-negative, peritrichously flagellated rods that conform to the family Enterobacteriaceae. E. coli can be differentiated from other genera in the tribus Escherichieae by indole production, the fermentation of lactose, negative reactions in KCN, gelatin, and malonate tests. E. coli is methyl red positive, Voges–Proskauer negative, and urease negative. E. coli group is heterogeneous and contains a very high number of stable subtypes. Therefore, it will be a difficult task to command all available methods in a single laboratory, if a complete typing of strains is needed.

2 Serotyping of Escherichia coli

The adhesion of Escherichia coli to human urinary tract epithelial cells was inhibited by commercial gamma globulin, the total immunoglobulin fraction of human breast milk and urine, as well as the isolated immunoglobulin G and secretory immunoglobulin A fractions of urine from patients with acute pyelonephritis. Urinary anti-O6 antibodies reduced the adhesion of several O6 strains. Absorption of antibodies to the lipopolysaccharide of the adhering strain markedly decreased the antiadhesive capacity of all the immunoglobulin preparations, whereas elimination of antibodies to the capsular polysaccharide antigen consistently had a small but not significant effect. When urine was absorbed with whole, live bacteria of the patients' infecting strains, the antiadhesive effect completely disappeared. Absorption with bacteria lacking pili only partially reduced this effect.

https://iai.asm.org/content/iai/22/3/790.full.pdf

Secretory immunoglobulin A and G antibodies prevent adhesion of Escherichia coli to human urinary tract epithelial cells.

Appearance of secretory IgM and IgA antibodies to Escherichia coli in saliva during early infancy and childhood

Secretory IgA antibody response against Escherichia coli antigens in infants in relation to exposure.

To evaluate the role of immunologic mechanisms in one specific syndrome of food intolerance in infants, food protein-induced enterocolitis, we measured class-specific serum antibodies to three food proteins, ovalbumin, soy, and cow milk, prior to diagnostic food challenges in 18 infants suspected to have this syndrome. Infants with positive challenge reactions to egg, soy, or cow milk had 5-10 times higher levels of IgA antibody directed against that food than did the infants with negative challenges. Levels of IgG antibody to soy and egg were also significantly higher (greater than 10-fold) in infants with positive challenge responses. There was no significant difference in levels of IgM food antibodies between the two groups. IgA anti-soy antibody levels rose in all 12 infants tested 2-10 weeks after a single soy feeding (challenge). However, IgM anti-soy antibody increased in the five infants who had a negative response to the challenge feeding and decreased in those seven with a positive response. The difference between the two groups was statistically significant (P less than 0.01). Some correlation existed (r = -0.68) between the increase in IgA anti-soy antibody and the decrease in IgM anti-soy antibody for infants with positive soy challenges. Although a pathogenic role for these antibodies is not proven, the findings suggest an altered immunologic response to ingestion of food antigens in infants with food protein-induced enterocolitis.

/pdf/food-protein-induced-enterocolitis-altered-antibody-response-10rgz92vwo.pdf

Food protein-induced enterocolitis: altered antibody response to ingested antigen.

Antibodies of different immunoglobulin classes possess various biological activities. Often, these are not closely related to their serological titres, determined by various techniques [l]. The reason for this discrepancy is that serological methods mostly favour antibodies of one or the other immunoglobulin class [2]. An immunological assay which reflects correctly the amounts or activities of the antibodies of the different immunoglobulin classes would be advantageous. The enzyme-linked immunosorbent assay (ELISA) is a technique with possibilities for correctly recording the capacity of antibodies to bind to a solid-phase-coupled antigen irrespective of the immunoglobulin class [l, 141. We have used the ELISA to quantitate antibodies of the different immunoglobulin classes, including antibodies carrying secretory component (SC) specific for various Escherichia coli antigens. During this work we attempted to elucidate the relation between the presence and amount of specific antibodies and their protective capacity during infections. The ELISA titres expressed in different ways were compared with the antibody titres determined with other serological techniques often used for serological diagnosis and in research. These tests included the indirect haemagglutination (IHA) method [22], the indirect haemolysis (IHL) method [22], and the ammonium sulphate precipitation (ASP) technique [7]. This communication describes some of our experiences with the ELISA for quantitation of antibodies in connection with exposure to E. coli antigens in patients and in experimental animals.

Application of the ELISA for Determination of Immunoglobulin Class‐specific Escherichia coli Antibodies

Several virulence factors, such as O and K antigens and capacity to attach to uroepithelial cells, seem to be required for Escheria coli to cause acute pyelonephritis. These factors induce an immune response, however, which can modify the course and clinical expression of the infection. During acute pyelonephritis, autoantibodies to the Tamm-Horsfall protein increase. These antibodies, which probably are evoked by a cross-reaction noted between structures of E. coli LPS and the Tamm-Horsfall protein, may add to the renal tissue engagement in interstitial nephritis caused by bacterial pyelonephritis.

B. Kaijser

Papers

Application of the ELISA for Determination of Immunoglobulin Class‐specific Escherichia coli Antibodies

Immunological Aspects of Pyelonephritis