[CANCER RESEARCH 44, 5439-5443,
November 1984]
Potentiation of Human Cell-mediated and Humoral Immunity by Low-Dose
Cyclophosphamide1
David Berd,2 Henry C. Maguire, Jr., and Michael J. Mastrangelo
Fox Chase Cancer Center, Philadelphia 19111 [D. B., ».C. M., M. J. M.¡;University of Pennsylvania School of Medicine, Philadelphia 19104 [D. B.¡;Hahnemann
Medical College, Philadelphia 19102 [H. C. M.]; and Temple University School of Medicine, Philadelphia, Pennsylvania 19140 [M. J. M.]
responses, and immunity to tumor-associated
ABSTRACT
Although Cyclophosphamide (CY) is a potent immunosuppressive drug, under the proper conditions, it can potentiate immune
responses as well. In past work, we have shown that adminis
tration of a commonly used oncostatic dose of CY (1000 mg/
sq m) to patients with advanced cancer 3 days before sensitization with the primary antigen, keyhole limpet hemocyanin
(KLH), resulted in augmentation of delayed-type hypersensitivity
(DTH) but not antibody response to that antigen. The present
study was performed to test the ¡mmunopotentiation of a lower
dose of CY (300 mg/sq m); animal studies and studies of human
lymphocytes in vitro suggested that the lower dose might be
more effective. Eighteen patients with advanced metastatic can
cer were alternately assigned to one of two groups. Sixteen
days before CY, one group received KLH and the other group
received 1-chloro-2,4-dinitrobenzene (DNCB). CY 300 mg/sq m
was given as an i.v. bolus on Day 0. Three days after CY, the
patients received KLH or DNCB, whichever they had not received
initially. Blood was drawn for antibody titer, and skin testing was
performed 14 days after administration of KLH or DNCB. In
addition, skin tests to microbial recall antigens were made 2
days before and 17 days after CY.
Pretreatment with low-dose CY resulted in significant augmen
tation of DTH to KLH; thus, the median DTH responses were:
KLH alone, 10 mm; and KLH after CY, 27 mm (p < 0.01). CY
pretreatment also resulted in augmentation of the antibody re
sponse to KLH. The median total antibody titers (Iog2 of recip
rocal of dilution) were as follows: KLH alone, <1 ; and KLH after
CY, 3 (p < 0.01 ). All nine CY-pretreated subjects but only 4 of
9 controls developed measurable anti-KLH antibody titers. CY
pretreatment neither augmented nor suppressed the 48-hr chal
lenge reaction to DNCB. Moreover, CY had no effect on DTH
responses to the recall antigens, dermatophytin, Candida, and
mumps.
INTRODUCTION
CY3 is a potent immunosuppressive
drug in experimental
animals and in humans (13, 16). However, it is now well estab
lished that, under the proper experimental conditions, CY can
potentiate immune responses as well (12). Thus, in a number of
animal systems, CY has been shown to augment DTH, antibody
1Supported
by USPHS Grant CA32123
and by an appropriation
from the
Commonwealth of Pennsylvania.
2 Current address: Thomas Jefferson University, Division of Medical Oncology,
1025 Walnut St., Philadelphia, PA 19107. To whom requests for reprints should
be addressed.
3 The abbreviations used are: CY, Cyclophosphamide; DNCB, 1-chkxo-2,4dinitrobenzene; DTH, delayed-type hypersensitivity; PBS, phosphate-buffered sa
line; KLH, keyhole limpet hemocyanin; i.d., intradermal.
Received April 19,1984; accepted August 10,1984.
NOVEMBER
1984
antigens (10,17).
Of particular interest is the ability of CY to break immunological
tolerance and even to facilitate the immunological rejection of
normal autologous tissue (18).
Cy-induced ¡mmunopotentiation requires the administration of
antigen, and the timing of CY and antigen is critical. For example,
giving CY to guinea pigs 2 days before sensitization with 2,4dinitrofluorobenzene increased the contact hypersensitivity re
sponse 4-fold, whereas giving CY 2 days after sensitization
completely suppressed it (17).
The phenomenon of CY-induced ¡mmunopotentiation could be
of great importance in cancer immunotherapy. The hypothesis
that tumor-bearing hosts initially develop immunity to their tu
mors but subsequently become tolerant to them has considera
ble experimental support (reviewed in Ref. 6). It raises the
question of whether the proper administration of CY to cancerbearing humans could reverse tolerance and result in the immunologically based rejection of tumor tissue.
In our initial study (5), we observed that the administration of
a commonly used oncostatic dose of CY, 1000 mg/sq m, to
patients with advanced cancer 3 days before sensitization with
the primary antigen, KLH, resulted in augmentation of DTH to
that antigen. The antibody response to KLH was unchanged.
We now report that a much lower and minimally toxic dose of
CY (300 mg/sq m) not only augments DTH but increases the
antibody response as well.
MATERIALS AND METHODS
Patients. Eighteen patients with advanced metastatic cancer were
studied, 8 with malignant melanoma, 8 with colorectal carcinoma, 1 with
breast carcinoma, and 1 with adenocarcinoma of the lung. Informed
consent was obtained. After stratification for tumor type, age, sex,
Karnovsky status, and prior treatment, they were alternately assigned
to 1 of 2 groups. A summary of pertinent clinical characteristics of the
study subjects in each group is shown in Table 1. The groups did not
differ significantly in regard to any of these characteristics. No patient
had received chemotherapy in the 4 weeks or major field radiation
therapy in the 8 weeks prior to entry on the study; none received
corticosteroids or other ¡mmunomodulating drugs immediately prior to or
during the testing. No patient exhibited tumor regression in response to
CY. All but 3 patients, one in Group I and 2 in Group II, have died.
A base-line measurement of the ability of patients to develop DTH
responses to microbial recall antigens was obtained by summing the
pretreatment DTH responses to dermatophytin, Candida antigen, and
mumps antigen for each patient and comparing the totals of patients in
Group I with those in Group II. Although most patients responded to at
least one recall antigen, the DTH responses were generally tow and were
similar in the 2 groups.
Study Design. The immune response to the primary allergens KLH
and DNCB was measured before or after the administration of CY 300
mg/sq m i.v. according to the protocol outlined in Chart 1. Group I
patients were pretested with KLH and posttested with DNCB. Group II
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D. Berd et al.
Table 1
Summary of clinical characteristics
IgG was used. Then the plates were washed, and 0.1 ml of substrate
was added to each well. The substrate solution consisted of 4 mg of O-
of patients
II4/4/162
phenylenediamine (Sigma Chemical Co., St. Louis, MO) and 0.005 ml of
a 30% solution of hydrogen peroxide added to 10 ml of a citrate buffer.
The citrate buffer consisted of 25.7 ml of solution A (N^HPCu, 36.
g:water, 500 ml), 24.3 ml of solution B (citric acid monohydrate 10.5
(49-71)66/9
(35-72)7/9
g:water, 500 ml), and 50 ml of water. The plates were incubated at room
men70(60-100)7/92/99/915
men60
temperature until the positive control wells reached an absorbance of
(40-90)8/93/98/911
about 0.500 and were then read in an enzyme-linked immunosorbent
No.coloréela!carcinomas/no,
of melanomas/no, of
of other carcino
masAge
(yr)SexKamovsky
statusPrior
chemotherapyPrior
therapyVisceral
radiation
métastasesDTH
antigens0Survival
to recall
(7-42)4(1-8+)•
(7-25)2(1-17+)Group
(mo)Group!4/4/165a
Median.
ivieuiaii.
6 Numbers in parentheses, range.
c Sum of the DTH responses to dermatophytin,
Candida antigen, and mumps
antigen.
IDayKLHSens.I*-16KLH
Group
ONCBChali
Sens.DCM
1t
!tCy-2,
+3Cy1i
0
i
Group H
DNCB
Sens.
DNCB
Chali
DCM
17
lDNCBChaliDCMt+
KLH
Sens.
KLH
Chali
DCM
Chart 1. Design of study. Sens., sensitizaron dose; Cha«,challenge dose; DCM,
skin testing with dermatophytin, Candida antigen, and mumps antigen.
patients were pretested with DNCB and posttested with KLH. For each
allergen, the responses of Group I patients were compared with those
of Group II patients. As indicated in Chart 1, patients were given a
sensitizing dose of the first antigen and a challenge dose 14 days later.
After 48 hr, the DTH response was measured, and CY was administered.
Three days after CY, patients were given a sensitizing dose of the
second antigen and, 14 days later, they were given a challenge dose.
After 48 hr, the DTH response was measured. Serum for antibody
determination was collected before and 14 days after the initial injection
of KLH. In addition, 12 of the patients were tested for DTH response to
microbial recall antigens 2 days before and again 17 days after CY.
Antigens. KLH was obtained from Calbiochem-Behring Corp. (San
Diego, CA) and purified as described previously (5). Sensitization was
accomplished by injecting 1.0 mg s.c., and challenge consisted of the
i.d. injection of 0.1 mg. In addition, all patients were given a separate i.d.
injection of 0.1 mg KLH at the time of sensitization to document that
they did not have a fortuitously established sensitivity. DTH at 48 hr was
determined by measuring the largest and right-angles diameters of the
area of induration and calculating the mean.
Antibody to KLH was measured by an enzyme-linked immunosorbent
assay. Microtiter plates (Dynatech Laboratories, Alexandria, VA) were
coated overnight at room temperature with KLH, 1.0 HQin 0.1 ml of PBS
(NaCI, 7.2 g:Na2NPO4.12 H20, 1.4 g:KH2PO4, 1.2 g:sodium azide, 1.0
g:water, 1000 ml, pH 6.4). The plates were washed 3 times with PBS +
0.05% Tween-20 and then rinsed 4 times with water. Then PBS + 0.5%
BSA was added to the wells for 1 hr to block any uncoated binding sites
on the plastic surface. The plates were washed, serum samples serially
diluted in PBS were added to the wells, and the plates were incubated
at room temperature for 2 hr. After 3 more washes, a "developing" serum
conjugated to horseradish peroxidase (Cappel Laboratories, Malvem,
PA) was added at a predetermined optimal dilution in PBS + 0.5%
Tween-20, and the plates were incubated for 2 hr at room temperature.
To determine total anti-KLH antibody, goat anti-human immunoglobulin
(IgG, IgA, IgM) was used. To determine the IgG fraction, goat anti-human
5440
assay plate reader (Dynatech Laboratories, Alexandria, VA). Antibody
titer was defined as the reciprocal of the highest dilution of a test serum
(expressed as Iog2) that gave 50% antigen saturation (expressed as the
absorbance at full saturation divided by 2). The absorbance at full antigen
saturation was defined as the absorbance of the plateau region attained
with the lowest dilutions of a strongly positive antiserum obtained from
a normal volunteer immunized with KLH (7). Seventeen of the 18 subjects
had presensitization titers of <1. One patient had a presensitization titer
of 2, and only her rise in titer was used for analysis.
DNCB was obtained from BDH Chemicals (Poole, England) and was
freshly prepared before each application by dissolving in acetonexorn
oil (9:1 ). Sensitization was accomplished by the topical application of 2.0
mg of DNCB to a skin site on the volar surface of the forearm within the
confines of a 1-cm circle. All patients developed a primary irritant re
sponse, and none developed a 48-hr DTH response. Challenge consisted
of the topical application of 0.10 and 0.05 mg to separate skin sites on
the forearm. DTH reactions were scored positive if any of the concentra
tions produced a full circle of erythema and induration after 48 hr.
Dermatophytin and Candida antigen (Dermatophytin O) were obtained
from Hollister-Stier Laboratories (Spokane, WA). Mumps antigen was
obtained from Eli Lilly & Co. (Indianapolis, IN). Skin testing was performed
by the i.d. injection of 0.1 ml of the commercially prepared materials.
DTH reactions (mean diameter of induration) were measured after 48 hr.
RESULTS
KLH DTH. Pretreatment of patients with CY 300 mg/sq m
resulted in significant augmentation of DTH to KLH (Chart 2).
The median DTH responses of the 2 groups of subjects were as
follows: KLH alone, 10 mm; and KLH after CY, 27 mm (p <
0.01 ; Mann-Whitney U test, 2-tailed). The DTH reaction exceeded
15 mm in 8 of 9 CY-pretreated patients but in only 1 of 9 controls.
KLH Antibody Response. CY pretreatment also resulted in
augmentation of the antibody response to KLH (Chart 3). The
median total antibody titers (Iog2 of reciprocal of dilution) were
as follows: KLH alone, <1; and KLH after CY, 3 (p < 0.01;
Mann-Whitney U test, 2-tailed). All 9 CY-pretreated subjects but
only 4 of 9 controls developed measurable anti-KLH antibody
titers (p < 0.025; Fisher's exact test). Of the patients who
developed antibody to KLH, all but one exhibited a rise in titer of
IgG antibody that was similar to the rise in total antibody. There
was a correlation between the development of antibody and DTH
responses to KLH (Spearman rank correlation, 0.52; p < 0.01).
For example, 2 of 7 patients with DTH responses of 10 mm or
less developed antibody titers of more than 2, whereas 9 of 11
patients with DTH responses of greater than 10 mm did so.
However, in several patients, the antibody and DTH responses
were dissociated markedly.
DNCB DTH. CY pretreatment did not appear to affect the
development of DTH to the contact sensitizer DNCB as mea
sured by skin reactivity. Of 9 patients given DNCB without CY,
4 had positive skin reactions. Of 8 patients sensitized with DNCB
3 days after CY, only 2 developed positive reactions. The differ
ence (4 of 9 versus 2 of 8) is not significant (p > 0.10).
CANCER
RESEARCH
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VOL. 44
Potentiation of Immunity by Low-Dose CY
60
50
40,
XX
30
„ 6
M
X
X
25
20
XX
1 »h
I
B
_L
X
XX
X
10r-
x<
)•<
5 -
XX
XX
X
X
KLH Alone
KLH After
Cyclophosphamide
Chart 2. DTH responses to KLH. Patients were sensitized with KLH without
CY or 3 days after CY (300 mg/sq m). All patients were challenged with KLH i.d.
14 days after sensitizaron, and DTH was measured after 48 hr. X, size of the DTH
reaction of one patient.
DTH to Microbial Recall Antigens. The administration of CY
neither augmented nor suppressed the DTH responses to recall
antigens. As shown in Chart 4, the DTH responses to dermatophytin, Candida antigen, and mumps antigen determined 17 days
after CY were similar to the pre-CY values. For each patient, we
calculated the change in the size of the DTH response to each
antigen and then calculated the mean of the change for the entire
group. The results were as follows (mean of the differences
between the pre- and post-CY DTH responses): dermatophytin,
1.7 ± 1.2 (S.E.) mm; Candida, -0.4 ±0.7 mm; and mumps,
-0.7 ±1.2 mm; for all, p > 0.20, f test for nonindependent
xxxxx
KLH Alone
KLH After
Cyclophosphamide
Chart 3. Antibody response to KLH. Patients were given KLH without CY or 3
days after CY (300 mg/sq m). Serum was collected before and 14 days after KLH.
X, anti-KLH total antibody titer of one patient.
25
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to
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DISCUSSION
The idea that killing or damaging lymphocytes with cytotoxic
drugs can lead to immunopotentiation as well as immunosuppression is accepted widely by experimental immunologists
(12,17). The cytotoxic drug whose immunopotentiating effects
have been studied most extensively in animal systems is CY.
However, the concept that CY-mediated augmentation of human
immune responses might have important theoretical and thera
peutic implications has only recently begun to be developed.
We provided the first demonstration that CY can augment
human immune responses (5). Administration of CY 1000 mg/
sq m to patients with advanced cancer 3 days before sensitization with the primary antigen, KLH, resulted in significant potentiation of the DTH response to that antigen. The antibody re-
NOVEMBER
1984
o ooo•*
Dermatophytin
Candida
Antigen
Mumps
Antigen
Chart 4. DTH responses to microbial recall antigens. Patients were skin-tested
with dermatophytin, Candida antigen, and mumps antigen 2 days before CY (•)
and 17 days after CY (O). Each circle represents the response of one patient.
sponse to KLH and the development of DTH to the contactsensitizing agent, DNCB, both markedly depressed in these
patients, were not augmented by CY pretreatment. In this pub
lication, we have confirmed and extended our original observa-
5441
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D. Berd et al.
tion. We now demonstrate the following: (a) a much lower dose
of CY, 300 mg/sq m, is also effective in augmenting DTH; (6)
with that dose, the antibody response to KLH, as well as the
DTH response, is potentiated; and (c) DTH responses to recall
antigens are not affected by CY administration.
In our first study, we administered CY at a dose of 1000 mg/
sq m, because that is the dose most commonly used to achieve
oncostatic effects. However, that dose of CY causes consider
able clinical toxicity; more significantly, it resulted in marked
lymphopenia, with equal reductions in the numbers of circulating
B-cells, helper-inducer T-cells, and suppressor-cytotoxic T-cells
(4). We hypothesized that a lower dose of CY, in addition to
being less toxic, would immunopotentiate just as effectively as
would the higher dose. This hypothesis was based on animal
studies, in which doses of CY as low as 60 mg/sq m augmented
immunity (1), and on studies of human lymphocytes in vitro, in
which extremely low concentrations of the active metabolite, 4hydroperoxy-CY, augmented lymphocyte function (14).
As predicted, the administration of low-dose (300 mg/sq m)
CY 3 days before sensitization with KLH resulted in highly
significant augmentation of DTH to that antigen. Although this
study did not directly compare high-dose (1000 mg/sq m) with
low-dose (300 mg/sq m) CY, it seems reasonable to conclude
that the 2 dosages are about equally effective in augmenting the
DTH response to KLH. Our published study of high-dose CY
nately, the effect of the dose of CY on potentiation of antibody
responses in experimental animals has not been studied system
atically.
The DTH responses to microbial recall antigens of our study
subjects were neither augmented nor suppressed by CY 17 days
after administration of the drug. The lack of a suppressive effect
was to be expected in view of the abundant evidence that
established immune responses are much less susceptible to
suppression by cytotoxic drugs than are primary responses (16).
The lack of a potentiating effect on established DTH responses
is also consistent with the frequently made observation that it is
not CY alone that augments immune responses but CY admin
istered at the proper interval before antigen (15).
The mechanism of CY immunopotentiation in human is uncer
tain, but it probably involves inhibition of suppressor T-cell func
tion (14). We have shown that the administration of high-dose
CY (1000 mg/sq m) causes impairment of concanavalin A-inducible suppressor activity but no change in the ratio of helper:
suppressor T-cells as defined by cell surface markers (4). Bast
ef al. (2) have shown that lower doses of CY (200 to 400 mg/
sq m) can selectively deplete suppressor, i.e., OKT8+, T-cells.
Our studies of the effect of CY (300 mg/sq m) on lymphocyte
composition and function are the subject of another paper.4
The ability of low-dose CY to augment both cell-mediated and
antibody-mediated immunity to KLH in patients with advanced
was similar to the present study with regard to experimental
subjects, i.e., patients with advanced, metastatic solid tumors,
mainly melanoma and colorectal cancer, and was identical to the
present study in regard to experimental design. Neither low-dose
CY nor high-dose CY augmented the DTH response to DNCB
as determined in our studies. This result with DNCB is puzzling,
since CY has been shown to augment the acquisition of DNCB
(or DNFB) contact sensitivity in a variety of experimental animals
(12, 17). The result may turn on a nonspecific reduction in
cutaneous reactivity to epicutaneous irritants that has been
noted in severely ill patients (11). Alternatively, an augmentation
of the DNCB contact sensitivity response could have been
missed if that response peaked earlier or later than the 14-day
cancer raises the question of whether CY would have the same
effect on immunity to tumor-associated antigens. Our initial
studies in humans of the immunopotentiation by CY of an autologous tumor vaccine have been encouraging (3). Immunomodulation by CY and perhaps by other cytotoxic drugs or
biological agents in conjunction with an appropriate form of
tumor-associated antigen may have potential as anticancer ther
apy in humans.
point that we studied.
Pretreatment with low-dose CY did have an effect that we did
not observe with high-dose CY: augmentation of the antibody
response to KLH. In vitro studies indicate that human B-lymphc-
REFERENCES
cytes are more sensitive to the cytotoxic effect of CY than are
helper T-cells and that precursors of T-suppressor cells are the
most sensitive of all (14). It is possible that CY at either 1000 or
300 mg/sq m is toxic to pre-suppressor T-cells, while it spares
helper T-cells. However, the lower dose could be significantly
less toxic for B-cells, which would account for the dose-depend
ent effect on the antibody response.
Although most animal studies have emphasized the potentiation of cell-mediated immunity, there is abundant evidence that
CY can augment antibody responses to some antigens in mice
and guinea pigs. Turk and Parker (17) showed that CY pretreat
ment resulted in a marked increase in IgG hemagglutinating
antibody to the antigen DNP-BGG. Debre ef al. (9) reported that
CY pretreatment resulted in the development of an antibody
response to the random copolymer, L-glutamic acid^-Ltyrosine50, in strains of mice that were otherwise unresponsive
to this antigen. Chiorazzi ef al. (8) showed that CY enhanced the
IgE antibody response to hapten-protein conjugates. Unfortu
5442
ACKNOWLEDGMENTS
The authors wish to acknowledge the excellent technical assistance of Marsha
Hahn Golden, who developed and performed the antibody assays.
1. Askenase, P. W., Hayden, B. J., and Gershon, R. K. Augmentation of delayedtype hypersensitivity by doses of cyclophosphamide which do not affect
antibody responses. J. Exp. Med., 747: 697-701,1975.
2. Bast, R. C., Jr., Reinherz, E. L., Maver, C., Lavin, P., and Schtossman, S. F.
Contrasting effects of cyclophosphamide and prednisolone on the phenotype
of human peripheral blood leukocytes. Clin. Immunol. Immunopathol., 28:101 114,1983.
3. Berd, D., Maguire, H. C., and Mastrangelo, M. J. Augmentation of delayedtype hyper-sensitivity to tumor-associated antigens by treatment with autologous tumor cell vaccine preceded by cyclophosphamide. Proc. Am. Soc. Clin.
Oncd., 2: 56,1983.
4. Berd, D., Maguire, H. C., Jr., and Mastrangelo, M. J. Impairment of concana
valin A-inducible suppressor activity following administration of cyclophospha
mide to patients with advanced cancer. Cancer Res., 44:1275-1280,1984.
5. Berd, D., Mastrangelo, M. J., Engstrom, P. F., Paul, A., and Maguire, H.
Augmentation of the human immune response by cyclophosphamide. Cancer
Res., 42:4862-4866,1982.
6. Broder, S., and Waldman, T. A. The suppressor-cell network in cancer. N.
Engl. J. Med., 299:1335-1341,1978.
7. Butler, J. E. The amplified ELISA: principles of and applications for the
comparative Quantitäten of class and subclass antibodies and the distribution
of antibodies and antigen in biochemical separates. Methods Enzymol. 73:
482-512,1981.
8. Chiorazzi, N., Fox, D. A., and Katz, 0. H. Hapten-specific IgE antibody
response in mice. VI. Selective enhancement of IgE antibody production by
4 D. Berd, H. C. Maguire, Jr., and M. J. Mastrangelo, manuscript in preparation.
CANCER RESEARCH
Downloaded from cancerres.aacrjournals.org on June 14, 2017. © 1984 American Association for Cancer Research.
VOL. 44
Potentiation of Immunity by Low-Dose CY
9.
10.
11.
12.
13.
tow doses of x-irradiation and by cycfophosphamkte.J. Immunol., 777:16291637,1976.
Debre, P., Waltenbaugh, C., Dorf, M. E., and Benacerraf, B. Genetic control
of specific immune suppression. IV. Responsivenessto the random copolymer
L-glutamide^-L-tyrosine80induced in BALB/c mice by cyclophosphamide. J.
Exp. Med., 744: 277-281,1976.
Glaser, M. Augmentation of specific immune response against a syngeneic
SV40-induced sarcoma in mice by depletion of suppressor T cells with cyclophosphamide.Cell. Immunol., 48: 339-345,1979.
Johnson, M. W.. Maibach, H. I., and Salmon, S. E. Skin reactivity in patients
with cancer. Impaired delayed hypersensitivity or faulty inflammatory response? N. Engl. J. Med., 284:1255-1257,1971.
Maguire, H. C., Jr., and Ettore, V. L. Enhancement of dinitrochlorobenzene
(DNCB)contact sensitization by cyclophosphamidein the guinea pig. J. Invest.
Dermatol., 48:39-43,1967.
Maguire, H. C., Jr., Maibach, H. I., and Minisce, L. W. Inhibition of guinea pig
NOVEMBER
1984
14.
15.
16.
17.
18.
anaphylactic sensitization with cyclophosphamide. J. Invest. Dermatol., 36:
235-236,1961.
Ozer, H., Cowens, J. W., Colvin, M., Nussbaum-Blumenson.A., and Sheedy,
D. In vitro effects of 4-hydroperoxycyclophosphamideon human immunoregulatory T subset function. J. Exp. Med., 755: 276-290,1982.
Pdak, L, Getetek, H., and Turk, J. L. Reversal by cyclophosphamide of
tolerance in contact sensitization. Immunology,28: 939-942,1975.
Santos, G. W., Owens, A. H., and Sensenbrenner, L. L. Effects of selected
cytotoxic agents on antibody production in man: a preliminary report. Ann. N.
Y. Acad. Sci., 774:404-422,1964.
Turk, J. L., and Parker, D. Effect of cyclophosphamide on immunological
control mechanisms.Immunol. Rev. 65:99-113,1982.
Yoshida, S., Nomoto. K., Himeno, K., and Takeya, K. Immune response to
syngeneicor autologous testicular cells in mice. I. Augmented delayedfootpad
reaction in cyclophosphamide-treatedmice. Clin. Exp. Immunol.,38:211-217,
1979.
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Potentiation of Human Cell-mediated and Humoral Immunity by
Low-Dose Cyclophosphamide
David Berd, Henry C. Maguire, Jr. and Michael J. Mastrangelo
Cancer Res 1984;44:5439-5443.
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