Enterobacterial common antigen.

INTRODUCTION .............. ................................ 591 DISCOVERY AND DEFINITIONS ............................................. 591 SEROLOGICAL METHODS ............................................. 592 Hemagglutination (HA), Hemolysis, and Hemagglutination Inhibition (HAI) ... 592 Other Serological Methods ............................................. 593 CHEMISTRY .............................................. 594 Studies on Immunogenic Strains ............................................. 594 Studies on Nonimmunogenic Strains ......................................... 595 Chemical Identity of ECA ............................................. 600 GENETIC DETERMINATION OF ECA ......................................... 602 The rMe Genes .............................................. 602 Role of the rib Region ..................... ........................ 604 Mutants of a New, "rif," Type ............................................. 605 Genetics of ECA in Immunogenic Strains .................. .................. 606 Conclusions .............................................. 606 IMMUNOGENICITY ................. ............................. 607 Immunogenic Strains ............................................ 607 Interference by LPS ............... ............................. 610 Importance of the Form of Aggregation ...................................... 611 Immunological Tolerance? ............................................ 613 ECA IN THE BACTERIAL CELL ............................................ 614 CLINICAL IMPLICATIONS ............................................ 614 Immediate Biological Effects of ECA ........................................ 614 Is ECA a Virulence Factor? ............................................ 615 Prevalence of Antibodies to ECA ............................................ 615 ECA and anti-ECA Antibodies in Relation to Disease .......... ................ 616 Anti-ECA in Experimental Infection ......................................... 619 Antigenic Similarities Between ECA and Animal Tissues ........ .............. 620 OTHER CROSS-REACTIVITIES AND RELATED ANTIGENS ...... ............ 620 Various "Common" Antigens ................................................ 620 ManNUA-Containing Bacterial Antigens ................ ..................... 622 DISTRIBUTION OF ECA: TAXONOMIC IMPLICATIONS ....... ............... 622 SUMMARY ............ ..................................... 623 LITERATURE CITED ................ a 624