84
A. SARAGEA ET AL.
2. Various responses to the Schick test
The Schick test is a semiquantitative reaction showing toxin activity
(Table I). The level of circulating antitoxin which is required to protect
against diphtheria in all ordinary circumstances is 0.03 AU/ml serum.
More accurate estimations of serum antitoxin levels may be achieved by
tissue culture tests or better by intradermal titrations in rabbit, according
to Jensen’s method (1933).
The Schick test is a reliable susceptibility test useful in the investigation
of the immunity status as a result of mass immunisation. It is used to
control the antigenic potency of vaccines and of different immunisation
schemes.
T o control the disease in the community it is considered that 90-95%
should be Schick negative.
IV. ANTIGENIC STRUCTURE OF C. DIPHTHERIAE
A. General
Increasing importance has been ascribed during the last three decades
to the bacterial cell components of C. diphtheriae.
Interest has been correlated with the need to develop a method of typing
as in other bacterial species, and to explain the following:
(1) The phenomena of virulence and invasiveness.
(2) The occurrence of mild symptoms (atypical clinical form) in
(3) The spontaneous disappearance from healthy carriers harbouring
I n this connection it was important to develop a serological typing
method and to clarify whether there is any antibacterial immunity
and its role in protection against diphtheria.
immunised carriers (Favorova and Kostjukova, 1966).
atoxigenic bacilli.
B. Serological typing
A series of findings led to the assumption that C. diphtheriae contains
some cellular factors of virulence, besides toxin (Niggemeyer, 1955 ;
Solovieva and Ananieva, 1945), but further verification is needed. Before
Anderson et aZ.’s (1931) discovery concerning the existence of the three
biotypes (gravis, mitis and intermedius) a classification scheme for C.
diphtheriae was lacking. This led several authors to work on serological
classification. Progress in research on the serological relationships within
C. diphtheriae encountered difficulties when attempts were made to
A. SARAGEA ET AL.
2. Various responses to the Schick test
The Schick test is a semiquantitative reaction showing toxin activity
(Table I). The level of circulating antitoxin which is required to protect
against diphtheria in all ordinary circumstances is 0.03 AU/ml serum.
More accurate estimations of serum antitoxin levels may be achieved by
tissue culture tests or better by intradermal titrations in rabbit, according
to Jensen’s method (1933).
The Schick test is a reliable susceptibility test useful in the investigation
of the immunity status as a result of mass immunisation. It is used to
control the antigenic potency of vaccines and of different immunisation
schemes.
T o control the disease in the community it is considered that 90-95%
should be Schick negative.
IV. ANTIGENIC STRUCTURE OF C. DIPHTHERIAE
A. General
Increasing importance has been ascribed during the last three decades
to the bacterial cell components of C. diphtheriae.
Interest has been correlated with the need to develop a method of typing
as in other bacterial species, and to explain the following:
(1) The phenomena of virulence and invasiveness.
(2) The occurrence of mild symptoms (atypical clinical form) in
(3) The spontaneous disappearance from healthy carriers harbouring
I n this connection it was important to develop a serological typing
method and to clarify whether there is any antibacterial immunity
and its role in protection against diphtheria.
immunised carriers (Favorova and Kostjukova, 1966).
atoxigenic bacilli.
B. Serological typing
A series of findings led to the assumption that C. diphtheriae contains
some cellular factors of virulence, besides toxin (Niggemeyer, 1955 ;
Solovieva and Ananieva, 1945), but further verification is needed. Before
Anderson et aZ.’s (1931) discovery concerning the existence of the three
biotypes (gravis, mitis and intermedius) a classification scheme for C.
diphtheriae was lacking. This led several authors to work on serological
classification. Progress in research on the serological relationships within
C. diphtheriae encountered difficulties when attempts were made to