UNIVERSAL SEROLOGIC REACTION WITH LIPID ANTIGEN
III.
I N SYPHILIS*
REUBEN L. KAT-IN, Sc.D., AND ELIZABETH B. McDERMOTT
From the Serological Laboratory, University Hospital, University of Michigan, Ann Arbor,
Michigan
The universal serologic reaction in syphilis exhibits a distinctive serologic
pattern different from that noted in normal human beings2 and in animals. 3
A common characteristic of the universal serologic pattern in normal human
beings is the almost total absence of precipitation previous to the incubation of
the serum-antigen mixtures and the presence of but limited precipitation in
particular zones following incubation of the mixtures at cold temperature. In
animals, a variety of serologic patterns is noted, but a common characteristic in
all is that precipitation is intensified by incubation at cold temperature. In the
universal serologic pattern in syphilis, almost maximal precipitation is noted on
mixing of the reagents, and precipitation is but little intensified by incubation at
cold temperature.
UNIVERSAL SEROLOGIC REACTION I N
SYPHILIS
Three hundred syphilitic serums were examined and an illustrative universal
reaction given by one serum is presented in Table 1. The universal serologic
technic, described in the first article of this series, consists of nine quantitative
precipitation tests, referred to as set-ups. Each of these set-ups consists of a
different salt concentration. Those, set-ups which include 0 to 0.3 per cent
sodium chloride concentrations are arbitrarily grouped under Zone I. Those
which include 0.6 to 1.2 per cent NaCl concentrations are grouped under Zone
IT, while the set-ups which include 1.5 to 2.1 per cent salt concentrations are
grouped under Zone III.
An outstanding characteristic evident from the data in the table, is the occurrence of precipitation without incubation of the serum-antigen mixtures.
Following incubation at cold temperature, an increase in precipitation is noted
in Zones I and III and but relatively little increase in Zone II. In this zone,
the quantitative set-up with 0.9 per cent salt solution is of interest, for the titer
in this set-up is the same without incubation and after 4 and 24 hours' incubation.
Figure I illustrates graphically the precipitation results given by this serum.
It should be recalled that the quantitative set-up with 0.9 per cent NaCl solution is technically similar to the quantitative Kahn test for syphilis. The fact
that this set-up does not show an increase in precipitation on incubation at cold
temperature corroborates previous observations reported from this laboratory;
namely, that cold temperature generally does not enhance specific precipitation
reactions in syphilis, but does enhance nonspecific reactions.1
* Tins study has been conducted with the aid of a grant from the Office of Naval Research,
Medical Sciences Branch, Navy Department, Washington, D. C.
Received for publication, October 28, 194S.
401
402
KAHN AND McDERMOTT
TABLE 1
UNIVERSAL SEROLOGIC REACTIVITY WITH LIPID ANTIGEN
Quantitative precipitation results with increasing concentrations of NaCl solutions
ranging from 0 to 2.1 per cent, employing syphilitic serum.
CONCENTRATIONS OF N a C l (PER CENT) USED IN PREPARATION OF SERIAL DILUTIONS OF SERUM
SERIAL
DILUTIONS
OF SEBUM
Zone I
0
0.15
Zone II
0.3
0.6
0.9
Zone III
1.2
1.5
1.8
2.1
Readings made without incubation of scrum-antigen suspension mixture
1
1
1
1
1
1
1
1
1
1
1
2.5
5
10
20
40
80
160
320
640
4
4
4
4
4
4
4
4
4
4
4
4
2
—
—
—
—
—
4
2
4
2
4
2
4
4
—
—
—
—
—
—
—
—
—
—
:
—
—
—
—
—
:
—
—
:
—
4
4
2
-
4
4
4
2
—
:
—
—
—
4
4
4
4
2
:
—
Readings after 4 hours' incubation in ice box
1
1
1
1
1
1
1
1
1
1
1
2.5
5
10
20
40
SO
160
320
640
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
2
±
—
—
—
—
4
4
4
4
±
—
—
—
—
•—
4
4
2
—
4
4
4
2
4
4
4
4
—
±
—
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Readings after 24 hours' incubation in ice box
1
1
1
1
1
1
1
1
1
1
1
2.5
5
10
20
40
SO
160
320
640
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
3
2
±
—
—
4
4
4
±
—
—
—
—
—
4
4
—
—
—
—
—
—
—
4
4
4
2
±
—
—
4
4
4
4
3
±
±
—
—
Figure 2 presents the serologic precipitation pattern of another syphilitic
serum. Here also maximal precipitation is obtained, especially in Zone II, after
mixing the serum with the lipid antigen suspension, and practically no increase
in precipitation is noted in this zone after 4 and 24 hours' incubation at cold temperature.
SEROLOGIC REACTIONS IN SYPHILIS
403
SYPHILITIC SERUM
WITHOUT INCUBATION
TIO
320
O
O
160
</).-»
u
80
at
ztf
.
40
u
?0
o<
10
I
AFTER 24 HOURS INCUBATION
IN ICEBOX
640
m
z
t-^
AFTER 4 HOURS INCUBATION
IN ICEBOX
tfll-
Zjf
t-o
-"d^°,
o
2
5
2.5
r/,
I
/
,
/<<%
\ >
t
p/
V/
// /A
'A /A
'/,.
.6 .9 1.2 1.5 1.8 2.1
X////A
.3 .6 .9 1.2 1.5 1.8 2.1
C O N C E N T R A T I O N OF NaCl [1-)
ZONE OF POSITIVE- REACTIONS
I.5 I.8 2.I
ZONE OF NEGATIVE REACTIONS
RH I
FIG. I. Zones of precipitation, with NaCl concentrations ranging from 0 to 2.1 per cent without
incubation and after 4 and 24 hours' incubation in ice box.
SYPHILITIC SERUM
WITHOUT INCUBATION
AFTER 4 HOURS INCUBATION
IN ICEBOX
AFTER 24 HOURS INCUBATION
IN ICEBOX
1.2 1.5 1.8 2.1
C O N C E N T R A T I O N OF NaCl (?•)
JM I
X////A
ZONE OF POSITIVE REACTIONS
ZONE OF NEGATIVE REACTIONS
FIG. 2. Zones of precipitation, with NaCl concentrations ranging from 0 to 2.1 per cent without
incubation and after 4 and 24 hours' incubation in ice box.
Figures 3 and 4 illustrate essentially the same findings as above with syphilitic
serums giving relatively strong precipitation reactions. The common char-
404
KAHiV AND McDERMOTT
SYPHILITIC SERUM
AFTER 24 HOURS INCUBATION
IN ICEBOX
AFTER 4 HOURS INCUBATION
IN ICEBOX
WITHOUT INCUBATION
.3
.6
.9
1.2 1.5
1.2 1.5
IS 2.1
1.8 2.1
CONCENTRATION OF NaCl (?.)
CB I
X////A
ZONE OF NEGATIVE REACTIONS
ZONE OF POSITIVE REACTIONS
F I G . 3. Zones of precipitation, with NaCl concentrations ranging from 0 to 2.1 per cent without
incubation and after 4 and 24 hours' incubation in ice box.
SYPHILITIC
.6- .9
1.2 1.5
AFTER 24 HOURS INCUBATION
IN ICEBOX
AFTER 4 HOURS INCUBATION
IN ICEBOX
WITHOUT INCUBATION
.3
SERUM
1.8 2.1
0
.3
.6
.9
12 1.5
1.8 2.1
.6
.9
I.2 I.5
IB 2J
CONCENTRATION OF NaCl [1-)
V///A
ZONE OF POSITIVE REACTIONS
I
I ZONE OF NEGATIVE REACTIONS
I '-I
F I G . 4. Zones of precipitation, with NaCl concentrations ranging from 0 to 2.1 per cent without
incubation and after 4 and 24 hours' incubation in ice box.
acteristic exhibited by the reactions of each of these serums is that, in the precipitation set-up with the 0.9 per cent salt concentration, the results are the same
without incubation and after 4 and 24 hours' incubation.
SEROLOGIC REACTION'S IN SYPHILIS
405
Figure 5 illustrates a reaction given by a syphilitic serum which is an exception
to the rule. In this reaction, an increase in precipitation following incubation
at cold temperature is noted. This increase has been noted especially in certain
instances in patients with primary syphilis and it may be a common manifestation of this stage of syphilis. The increase may also be due to the particular
serologic pattern given by the donor before becoming infected with syphilis.
Thus, a donor showing under normal conditions marked precipitation following
incubation at cold temperature, will continue to show the same tendency after
becoming infected with syphilis.
SYPHILITIC
WITHOUT INCUBATION
SM I
X////A
SERUM
AFTER 4 HOURS INCUBATION
IN ICEBOX
ZONE OF POSITIVE REACTIONS
I
AFTER 24 HOURS INCUBATION
IN ICEBOX
I ZONE OF NEGATIVE REACTIONS
F I G . 5. Zones of precipitation, with NaCI concentrations ranging from 0 to2.1 per cent without
incubation and after 4 and 24 hours' incubation in ice box.
NATURE OF UNIVERSAL SEROLOGIC REACTION IN SYPHILIS
I t was stated in the previous articles that the universal serologic reaction given
by normal human beings and by animals may represent a reaction between lipid
antigen and natural antibodies called forth by lipids liberated in tissue wear and
tear. If so, the universal serologic reaction in S}'philis may represent a reaction
between acquired antibodies and tissue lipids liberated as a result of destructive
processes associated with the syphilitic infection. An examination of the table
and figures suggests that in syphilis two situations occur which affect the lipid
antigen-antibody reactions: (1) Some increase over the normal liberation of tissue
lipids occurs which results in a corresponding increase in antibody production,
and (2) A marked liberation of particular lipids occurs, and these call forth the
production of antibodies characteristic of syphilis. It is possible that the enhancement of precipitation on incubation at cold temperature, in Zone I of
reduced salt concentration and in Zone III of increased salt concentration, is the
40G
KAHN AND McDERMOTT
result of an increase in antibodies similar to those produced under normal conditions. On the other hand, the precipitation which occurs in Zone II without
incubation and which is little increased by incubation at cold temperature is the
result of antibodies characteristic of syphilis.
Are the antigenic lipids responsible for these characteristic antibodies in
syphilis totally different serologically from the lipids liberated in normal tissue
wear and tear? The answer most likely is that they are not totally different, for
the same lipid antigen is employed in vitro in the detection of syphilitic and
normal antibodies to lipids. It would appear that heart muscle, the base for
antigen production, contains some lipids, very likely in small amounts, that are
characteristic not only of syphilis but also of other diseases. However, in syphilis
a preponderance of lipids characteristic of that disease is most likely liberated,
resulting in a preponderance of specific antibodies which are capable of reacting
in vitro with the specifically antigenic lipids present in the heart muscle extract.
Similarly, in lepromatous leprosy, a preponderance of lipids characteristic of that
disease is liberated which call forth a relatively large number of specific antibodies. These, in turn, are capable of reacting with the lipids characteristic of
that disease present in the heart extract.
As a working hypothesis, it might be assumed that the heart extract antigen
contains many different antigenic lipids, let us say A, B, C, D, E, F, G, H, I, J,
K, etc. Under normal wear and tear of tissues, lipids A, B and C are liberated
and these call forth the production of a, b and c antibodies. These antibodies
present in the serum of normal persons react in the universal serologic technic
with the lipids A, B and C contained in the antigen and not with the other lipids.
In syphilis, tissue lipids D, E and F are also liberated and they call forth (in
addition to a, b and c) d, e and f antibodies. The universal reaction in this
disease, therefore, consists of antigenic lipids A, B, C, D, E and F reacting with
antibodies a, b, c, d, e and f. Perhaps in lepromatous leprosy, a preponderance
of lipids G, H, and I are liberated which in turn call forth a corresponding preponderance of antibodies g, h and i, and these react with G, H and I lipids in the
antigen. Thus, with the same antigen it is possible to meet with different serologic patterns.
I t should be added that the universal serologic reaction is not proposed as a
new diagnostic agent in syphilis. The main value of the universal reaction, insofar as syphilis is concerned, lies in the light it throws on the nature of the serodiagnostic reaction in this disease. This reaction, as already stated, represents
but. one facet of the multifaceted universal reaction. The use of the singlefaceted serodiagnostic reaction in practice led to the common finding that a negative reaction in the absence of syphilis changes to a positive reaction in the presence of this disease, which in turn led to the belief that syphilis calls forth the
development of a new serologic reaction.
In the study of the multifaceted universal reaction in syphilis, however, one
finds that this disease calls forth not a new reaction, but the enhancement of a
pre-existing reaction. This enhancement has been noted also under experimental conditions in this laboratory. In unpublished studies in rabbit syphilis,
SEROLOGIC REACTIONS IN SYPHILIS
407
the normal universal reactions before infection, undergo enhancement following
the infection. Of interest is the fact that this enhancement of the universal
reaction, as will be evident from the data reported in this series of articles, occurs
also in other diseases; namely, in leprosy, malaria and tuberculosis. The universal reaction is undoubtedly enhanced also in still other diseases. I t would
thus appear that this enhancement is a phenomenon which is not limited to
syphilis, but is part of a widespread biologic manifestation in which lipid antigenantibody reactions in health become enhanced in disease.
Returning to the serodiagnosis of syphilis, the serodiagnostic technic being a
restricted portion of the universal technic, the serodiagnostic reaction is necessarily a restricted portion of the universal reaction. If then the universal reaction is a widespread biologic manifestation, the serodiagnostic reaction must
similarly be a widespread manifestation. I t is thus understandable why serodiagnostic tests for syphilis give positive reactions not only in syphilis but under
a variety of conditions in the absence of this disease.
SUMMARY
The universal serologic reaction in human beings with syphilis is characterized
by a distinctive serologic pattern different from that given by normal human
beings and by animals of different species. In that reaction, precipitation occurs
rapidly on mixing the serum with the lipid antigen suspension and in most instances is not enhanced by cold incubation, especially in the precipitation zone of
approximately physiologic salt concentration.
REFERENCES
1. K A H N , R. L . : A serologic verification test in the diagnosis of l a t e n t syphilis. Arch.
D c r m a t . and Syph., 4 1 : 817-830, 1940.
2. K A H N , R. L.: Universal serologic reaction with lipid antigen. I. I n normal persons.
Am. J . Clin. P a t h . , 19: 347-360, 1949.
;•'. K A H N , R. L., AND BARIBEAU, B . J . : Universal serologic reaction with lipid antigen. I I .
In animals. Am. J. Clin. P a t h . , 19: 361-36S, 1949.