A Study of the Vi Antigenic Fraction of Typhoid Bacilli Isolated from Carriers and Cases, and the Antibody Content of the Serum of These Patients

The Significance of the Vi Antigen

“…Among the cases in which the clinical record was studied along with the bacteriological findings, no correlation could be shown to exist between the degree of development of Vi antigen in the cultures isolated and the severity of the disease (29,58,1,57). However, there is no satisfactory method in use for evaluating the quantitative development of the Vi antigen, and the problem is further complicated by differences in immunological response among individuals, which is also difficult to measure.…”

“…The purpose of this review is to take bearings on how much progress has been made as a result of the studies thus stimulated, and to call attention to places where a strengthening of evidence would be desirable.Occurrence. Almost all freshly isolated typhoid cultures have been shown to contain the Vi antigen (29,46,20,1,66,57). In addition, it has been found sporadically in some of the Hirschfeld paratyphoid C strains (46), in a species of Salmonella designated as "ballerup" (49), and in a few cultures of the coli group (48).Strains of Eberthella typhosa which possess the antigen do not differ noticeably in cultural reactions (including fermentative ability) from those which lack it, although Giovanardi (36) reports that colonies of the Vi-containing form are somewhat more opaque than those of the forms not containing it.Properties.…”

“…Occurrence. Almost all freshly isolated typhoid cultures have been shown to contain the Vi antigen (29,46,20,1,66,57). In addition, it has been found sporadically in some of the Hirschfeld paratyphoid C strains (46), in a species of Salmonella designated as "ballerup" (49), and in a few cultures of the coli group (48).…”

“…All studies to date indicate that human infection is almost always brought about by cultures containing Vi antigen (29,46,20,1,66,57). The exceptional cases in which Vi antigen was not demonstrated in cultures isolated from cases and carriers cannot be cited as evidence of infection without the presence of this antigen, since no systematic attempts to isolate other cultures from the same patients were made.…”

Agglutination tests in the diagnosis of enteric fever in the inoculated

“…But the production of this antibody in amounts that can be titrated seems to be irregular and transitory. In some cases examined regularly throughout the disease Vi agglutinins were not demonstrated (Felix, Krikorian & Reitler, 1935;Almon, Read & Stoval, 1937;Pijper & Crocker, 1939;Almon & Stoval, 1940;Bensted, 1940;Eliot, 1940). Further, although the Vi agglutinins were at first considered specific for typhoid fever (Bhatnagar, 1938), they have been found in fevers that were not of the enteric group (Seshadrinathan & Pai, 1940;Bensted, 1940), and appear in normal subjects after inoculation with the newer vaccines (Felix, Rainsford & Stokes, 1941).…”