Antigenic Analyses of Lactobacillus fermenti

Abstract

Antigenic analyses of Lactobacillus fermenti were carried out by double immunodiffusion in agar using extracts prepared with cold trichloroacetic acid (TCA) or hot dilute hydrochloric acid (HCl). A common antigen of L. fermenti, designated as antigen f by the author, was extracted from whole cells with dilute HCl, but not with TCA. The antigen f was also observed in Lactobacillus casei. In addition, all strains isolated from human saliva contained antigen 6 in their cell walls, while the antigen was not observed in most of the isolates from human feces. Therefore, L. fermenti could be divided into two subgroups based upon the existence of antigen 6. Antigen 7 which was demonstrated in some strains of L. fermenti was shared by other species of lactobacilli belonging to the serological groups D and E. The common antigen 3 found in lactobacilli was extracted from all strains of L. fermenti. Sugar components of cell walls were mainly galactose, glucose and glucosamine (including N-acetylglucosamine), but a small amount of rhamnose was present in the cell wall of only one strain. Inhibition tests with various sugars showed that the serologically active sugars were galactose for antigen f and glucose for antigen 6.

Grouping Antigens of Four Lactobacillus Species and Their Characteristics

“…The two antigens present in the cell wall are considered to be significant in the classification and identification of these species. All the strains also possessed antigens 3 and 7 in the intracellular fractions of their cells but not in the cell walls as previously described [9,10]. Sharpe [7] has assigned the four species to group E on the basis of the presence of a specific antigen in extensive serological studies.…”

“…Our interpretation is that the immunogenic capacity of antigen 9 or 10 of strains YIT 0077 and L-20 is very weak or lost in spite of the normal precipitinogen, and the other strains did not produce antibody 9 or 10 (or both the antibodies) in their antisera. All the extracts also possessed antigens 3 and 7, since they reacted with antisera against L. casei strain C-5 and L. fermenti strain 37 representing the precipitation patterns specific for the two antigens described previously [9,10]. Similar experiments were performed using every strain in various combinations in agargels.…”

“…Although the chemical structures of bacterial teichoic acids have been fully studied in other species, particularly concerning the relationship of their antigenicities in many organisms [6], there have been no reports on the immunologically dominant component of the group E antigen. We [9,10] previously recognized the presence of two antigens in the strains of the four species showing precipitin lines in immunodiffusion tests with a few antisera against Lactobacillus casei and Lactobacillus fermenti. Such antigens seemed to be present in the cell membranes described by Sharpe [7].…”

“…In this work, antigenic compositions of L. bulgaricus, L. lactis, L. brevis and L.buchneri were investigated using agar-immunodiffusion tests, and further attempts were made to clarify the immunodominants of the antigens. [9] were used to examine cross reactions.…”