Vi-deficient and Nonfimbriated Mutants of Salmonella Typhi Agglutinate Human Blood Type Antigens and Are Hyperinvasive

FEMS Microbiol Lett. 1998 Apr 1;161(1):75-82. doi: 10.1111/j.1574-6968.1998.tb12931.x.

Abstract

We generated nonfimbriated mutants from both Vi-positive and -negative Salmonella typhi to analyze the role of type 1 fimbriae and Vi-antigen in bacterial invasion. A Vi-defective mutant of S. typhi GIFU 10007-3 was more invasive than the wild-type strain GIFU 10007. The wild-type strain expressing Vi-antigen did not agglutinate both Saccharomyces cerevisiae and human erythrocytes but Vi-defective mutants were able to agglutinate S. cerevisiae and human erythrocytes. Nonfimbriated mutants from Vi-negative GIFU 10007-3 lost the ability to adhere to S. cerevisiae but still could agglutinate human erythrocytes. The Vi-negative mutant increased secreted proteins and became 5-fold more invasive than the wild-type strain. Nonfimbriated Vi mutants became 50-120-fold more invasive than the wild-type GIFU 10007. To determine why nonfimbriated Vi mutants still agglutinate human red blood cells, we searched bacterial proteins that could bind human blood-type antigens. We finally identified a candidate 37 kDa outer membrane protein that recognized fucosyl-galactose, a structure common to blood type A, B and H antigens.

MeSH terms

  • ABO Blood-Group System / immunology*
  • Agglutination*
  • Antigens, Bacterial / physiology*
  • Bacterial Outer Membrane Proteins / metabolism
  • Fimbriae, Bacterial / physiology*
  • Humans
  • Mutation
  • Polysaccharides, Bacterial / physiology*
  • Salmonella typhi / physiology*

Substances

  • ABO Blood-Group System
  • Antigens, Bacterial
  • Bacterial Outer Membrane Proteins
  • Polysaccharides, Bacterial