| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Clinical Trials |
Department of Medicine, Division of Hematology/Oncology, University of Alabama at Birmingham, Comprehensive Cancer Center, Birmingham, Alabama 35294-3300 [R. M. C., K. O. A., S. E. M., D. R. S., A. F. L.], and Department of Dermatology, Faculty of Medicine, Kyushu University, Fukuoka 812-82 Japan [S-w. L.]
 |
ABSTRACT |
|---|
 Top ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
|
INTRODUCTION |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Recombinant vaccinia viruses encoding full-length or internally deleted cDNAs for human CEA are replication competent and direct cell surface expression of CEA (9) . Immunization with rV-CEA has induced CEA-specific humoral and cellular immune responses in mice and nonhuman primates as well as protection of mice against challenge with syngeneic colon carcinoma cells expressing human CEA (10 , 11) . However, it is important to emphasize that human CEA is a foreign antigen in both mice and nonhuman primates, whereas humans appear to be immunologically tolerant to CEA related to its expression in fetal and normal adult tissues. To provide a more suitable model for studying various immunotherapy strategies directed against this tumor self-antigen, transgenic mice that express human CEA with a tissue distribution similar to that of humans have been developed (12) . Immunization of these CEA transgenic mice with rV-CEA induced modest titers of IgG and IgM CEA antibodies, CEA-specific helper and cytotoxic T-cell responses, and protection against challenge with CEA-expressing tumor cells (13) . Anti-CEA IgG titers generated by repetitive rV-CEA immunization in CEA transgenic mice were approximately 40-fold lower than those measured in corresponding CEA-negative littermates, a difference that may be related to tolerance in the former group.
The first clinical trial of rV-CEA was conducted by the Navy Oncology Branch of the NCI in 26 patients with metastatic adenocarcinoma (14 , 15) . No primary lymphoproliferative responses to soluble CEA protein were observed, and no antibody responses to CEA were reported (14 , 15) . However, human leukocyte antigen-A2-restricted cytolytic T-cell lines responsive to specific CEA peptides could be derived by prolonged in vitro culture of peripheral blood lymphocytes from patients after vaccination (15) .
Subsequently, our group completed a NCI-sponsored Phase I clinical trial using rV-CEA in 20 patients with widely metastatic and predominantly colorectal adenocarcinoma (16) . Prevaccination serum CEA levels ranged from 1–3358 ng/ml among these patients. This study will hereafter be referred to as UAB 9619. In this trial, the recombinant vaccinia virus encoded the full-length cDNA for CEA (Mr 180,000). Patients were randomly assigned to receive the vaccine by either standard intradermal injection or s.c. jet injection. All patients received two doses of either 107 or 108 pfu of rV-CEA at a 4-week interval. Toxicity was limited to modest local inflammation at the inoculation site and low-grade fever and fatigue affecting a minority of patients. No evidence of CEA-specific lymphoproliferation, interleukin-2 release, or delayed type hypersensitivity was observed (16) .
Our group recently completed a second NCI-sponsored Phase I clinical trial using rV-CEA in 12 patients with Dukes’ stage C or D colorectal adenocarcinoma rendered free of detectable disease by standard treatment methods. This study will hereafter be referred to as UAB 9501. In this trial, the recombinant vaccinia virus encoded a Mr 70,000 truncated cDNA containing an in-frame deletion of two of the three CEA repeated domains (17) . One group of six patients received 4 x 107 pfu of rV-CEA by scarification at weeks 0 and 8. A second group of six patients received the same dose and schedule of rV-CEA plus 300 mg/m2 cyclophosphamide i.v. 3 days before each vaccine dose. No toxicities were observed except for modest local inflammation at the inoculation site and mild nausea attributable to cyclophosphamide. Whereas T-cell responses to vaccinia virus were observed, no lymphoproliferative responses to soluble CEA occurred before or after rV-CEA vaccination.
In this report, we present the analysis of serological immune responses to CEA among the 32 patients in the two trials of rV-CEA performed by our group. The data provide the first evidence for induction of anti-CEA autoantibodies in patients after rV-CEA vaccination.
|
MATERIALS AND METHODS |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
ELISA for Anti-CEA Antibodies.
To detect anti-CEA antibodies, microtiter plates were coated overnight
with 100 ng/well of baculovirus rCEA protein (MicroGeneSys). The plates
were blocked for 90 min at 37°C with 1% pig skin gelatin and 3%
nonfat dry milk in PBS (referred to as milk buffer with gelatin). The
plates were incubated with patient or normal donor sera diluted in milk
buffer without gelatin overnight at 4°C. Plates were washed, and
antibody binding was detected with HRP-conjugated goat antihuman IgG
(heavy and light chain) antiserum (1:5000; Jackson ImmunoResearch
Laboratories, Inc., West Grove, PA). This antiserum binds human IgA,
IgG, and IgM by virtue of light chain recognition. HRP activity was
detected by incubation with substrate, and absorbance was read at 405
nm. A positive anti-CEA antibody response was defined as a
posttreatment absorbance greater than twice the pretreatment absorbance
for the individual patient and greater than the mean plus two SDs of 10
normal donor sera assayed at the same dilution.
Competitive ELISA with Patient Antisera.
For competitive inhibition assays, patient sera obtained 5–8 weeks
after primary immunization were selected on the basis of producing the
highest absorbance in the ELISA for direct CEA binding. These sera were
diluted 1:30 in milk buffer with or without inhibitor protein, added
immediately to microtiter plates coated with baculovirus rCEA, and
incubated overnight at 4°C to allow antigen-antibody interactions to
reach equilibrium. The remainder of the ELISA was conducted as
described above. Inhibitor proteins consisted of baculovirus rCEA at
100 ng/ml or 100 µg/ml, human rCEA at 100 ng/ml or 100 µg/ml, or
BSA at 100 µg/ml as a negative control for nonspecific protein
inhibition.
The inhibitor concentration of 100 µg/ml was selected to provide a
100-fold excess of soluble CEA compared to the quantity of CEA used to
coat each well. Inhibition with 100 µg/ml baculovirus rCEA uniformly
reduced the ELISA absorbance in wells coated with the same CEA protein
by >75% and was used to define the background absorbance due to
nonspecific binding. The percentage of inhibition was calculated by the
following formula:
 |
where A is the absorbance produced by serum alone, B is the absorbance produced by serum plus an inhibitor (BSA or human rCEA), and C is the background absorbance due to nonspecific binding.
Western Immunoblot.
Either 10 µg of baculovirus rCEA (MicroGeneSys) or 30 µg of human
rCEA (Vitro Diagnostics) were preboiled in 2x SDS sample buffer and
loaded onto an 8% SDS-polyacrylamide gel. After electrophoresis and
electrotransfer onto a polyvinylidene difluoride membrane (Bio-Rad
Laboratories, Hercules, CA), the membrane was blocked for 1 h at
room temperature with 5% nonfat dry milk in PBS. The membrane was then
mounted on the Mini-Protean II Multiscreen apparatus (Bio-Rad
Laboratories), and each lane was filled with 200 µl of patient sera
diluted 1:3 or 1:10. Positive controls consisted of the COL-1 anti-CEA
monoclonal antibody (18)
or monkey polyclonal anti-CEA
serum (19)
diluted 1:100. All dilutions were in 5% nonfat
dry milk in PBS. After incubation overnight at 4°C on a rotator, the
membrane was washed by immersing the whole apparatus in 3 liters of PBS
at room temperature for 20 min with shaking. The wash process was
repeated once and followed by one wash with Tris-buffered saline [150
mM NaCl, 50 mM Tris-Cl (pH 7.5)].
Membrane-bound antibodies were detected by HRP-conjugated goat
antimouse IgG antiserum for COL-1 lanes or by HRP-conjugated goat
antihuman IgG antiserum (Jackson ImmunoResearch Laboratories, Inc.) for
lanes receiving monkey or patient sera. Each lane was incubated for
1 h at room temperature with the appropriate secondary antibody
diluted 1:4000 in 5% nonfat dry milk in PBS. The membrane was washed
four times in 200 ml of Tris-buffered saline for 10 min each at room
temperature on a rotator. The Opti-4CN substrate kit (Bio-Rad
Laboratories), was used for color development, whereas
Chemiluminescence Reagent Plus (NEN Life Science Products, Inc.,
Boston, MA) was used for luminescence detection and exposure to X-ray
film.
Antibody Isotyping Assay.
The immunoglobulin classes comprising anti-CEA antibody responses were
examined by the ELISA method described above with one alteration.
CEA-specific antibodies captured by plate-bound antigen were
detected with a panel of three secondary antisera (Jackson
ImmunoResearch Laboratories, Inc.), each at 1:5000 dilution:
(a) goat antihuman IgG (Fc) (IgG specific); (b)
goat antihuman IgM; or (c) goat antihuman IgA. Relative
quantities were depicted as absorbance values of sera obtained before
and after immunization using each detection antisera. A positive result
was defined as postimmunization absorbance at least 2-fold greater than
preimmunization absorbance. IgG subclasses were assessed using
HRP-conjugated anti-IgG1, anti-IgG2, anti-IgG3, and anti-IgG4
antibodies (The Binding Site, San Diego, CA). Standard curves were
generated with human myeloma proteins IgG1, IgG2, IgG3, and IgG4, all
with 
light chains (The Binding Site), and patient serum results
were normalized against these subclass standards. A positive IgG
subclass response was defined as posttreatment binding greater than the
mean plus two SDs of the pretreatment binding for the seven patients
tested.
Competitive ELISA with Monkey Anti-CEA Sera and Monoclonal
Anti-CEA.
Microtiter plates were coated overnight with 200 ng/well human rCEA
(Vitro Diagnostics) and blocked with milk buffer with gelatin.
Polyclonal monkey anti-CEA sera were generated by immunizing pig-tailed
macaques with plasmid DNA encoding human CEA by i.m. injection or
particle bombardment of the skin as described previously
(19)
. Antisera following primary immunization or first
boost were selected to provide relatively low titer, low affinity
anti-CEA antibodies resembling those observed in the vaccinated
patients. Postimmunization sera from three macaques and COL-1 anti-CEA
monoclonal antibody at 600 µg/ml in neat normal mouse serum were
diluted 1:100 in milk buffer without gelatin, followed by the addition
of human rCEA at concentrations ranging from 1–100,000 ng/ml
(corresponding to 102–107
ng CEA/ml neat serum after correcting for the 1:100 dilution). The
diluted sera containing soluble human rCEA were immediately added to
ELISA wells and incubated overnight at 4°C to allow antigen-antibody
interactions to reach equilibrium. The remainder of the ELISA was
conducted as described above with peroxidase-conjugated goat antihuman
IgG (heavy and light chain) and antimouse IgG (heavy and light chain),
each at 1:5000 (Jackson ImmunoResearch Laboratories), to detect monkey
antisera and COL-1, respectively.
Serum CEA Protein Quantitation.
Selected patient sera obtained 5–8 weeks after primary immunization
were spiked with human rCEA for final concentrations ranging from
0–100 ng/ml; normal donor sera were similarly spiked as controls. The
sera were assayed for CEA content in the hospital clinical laboratory
using the AXSYM system (Abbott Laboratories, Abbott Park, IL). This
system uses mouse monoclonal anti-CEA-coated microparticles to capture
soluble CEA and uses an alkaline phosphatase-conjugated mouse
monoclonal anti-CEA antibody for detection.
|
RESULTS |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Patients 1, 3, and 16
received rV-CEA by s.c. jet injection, whereas patient 11 received the
vaccine by standard intradermal injection. Anti-CEA antibodies
developed in one patient after primary immunization and developed in
four patients within 1 week after a boost.
|
anti-CEA antibody responses peaked 8 weeks after primary
immunization and remained detectable 8 weeks after a boost. Patients 2
and 4 received the vaccine alone, and patient 10 was pretreated with
cyclophosphamide. Failure of the boost to increase the anti-CEA
antibody titers may be due to host immune response to the vaccinia
virus vector (16)
.
Competitive ELISA with Patient Antisera.
We next sought to confirm that binding of patient antisera to ELISA
wells coated with baculovirus rCEA represented true CEA reactivity and
not reactions with trace viral or insect cell contaminants within the
CEA protein preparation. For this purpose, we examined the ability of
human rCEA produced in a stably transfected human cell line to
competitively inhibit antibody reactivity with baculovirus rCEA (Table 1)
. Human rCEA and an irrelevant control
protein, BSA, were each added at 100 µg/ml, corresponding to a
100-fold excess compared to the amount of CEA used to coat each ELISA
well. Excess soluble BSA as a control for nonspecific inhibition
reduced serum antibody binding to CEA by only 2–15%. However, soluble
human rCEA inhibited binding by 69–82%. These results indicate that
patient antisera recognized epitopes shared between human rCEA and
baculovirus rCEA, and not contaminants in the CEA preparation. This
result was expected because the patients were immunized with rV-CEA and
thus had no known exposure to contaminants that might be present in the
recombinant protein preparations.
|
, indicating that the ELISA used for the detection of serum
CEA autoantibodies would not be compromised by the patient’s
circulating CEA levels.
Western Immunoblot.
Sera from the four metastatic adenocarcinoma patients (protocol UAB
9619) demonstrating CEA autoantibody responses by ELISA reacted with
baculovirus rCEA protein by Western blot assay. As shown in Fig. 2
, the COL-1 anti-CEA monoclonal antibody
detected a diffuse band at approximately
Mr 120,000, corresponding to the
molecular weight of partially glycosylated baculovirus rCEA
(20)
. Postimmunization sera from all four patients
produced a similar band at approximately
Mr 120,000, whereas all
preimmunization sera were negative. Fig. 2
provides representative data
from two of the four patients.
|
, polyclonal
monkey anti-CEA serum (19)
produced a clear band at
approximately Mr 180,000,
corresponding to the molecular weight of fully glycosylated human CEA
(1)
. A panel of eight normal human sera and
preimmunization sera from all seven patients were negative, producing
no detectable bands. Fig. 3
provides data from three representative
patients whose postimmunization sera demonstrated a band at
approximately Mr 180,000.
|
. IgG was
the dominant class of anti-CEA antibody occurring in all seven
patients. IgM responses were observed in three of seven patients, and a
modest IgA response was seen in only one of seven patients. IgG
anti-CEA antibodies were almost exclusively of the IgG1 subclass, with
levels as high as 3 µg bound per milliliter serum (Table 2)
. Modest levels of IgG3 anti-CEA
antibodies occurred in two of seven patients, whereas no IgG2 or IgG4
anti-CEA antibodies were detected.
|
|
illustrates the binding of 1:100
dilutions of these antisera to solid-phase human rCEA in the presence
of varying concentrations of soluble human rCEA. For the three monkey
antisera, the mean ± SE IC50 is 62,000 ± 10,000 ng CEA/ml neat serum. Alternatively, a serum CEA
concentration of 105 ng/ml is required to
decrease the ELISA absorbance comparable to a half-log decrease in
monkey antibody concentration (data not shown). For comparison, Fig. 5
also provides a competitive inhibition curve for COL-1 anti-CEA
monoclonal antibody with varying concentrations of human rCEA. The
IC50 decreased to 1,200 ng CEA/ml neat serum when
this monoclonal antibody with high affinity for soluble CEA was used.
|
|
DISCUSSION |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Here, we provide the first demonstration that CEA autoantibodies can be induced by vaccination with a recombinant vaccinia virus. CEA antibodies were induced after vaccination with rV-CEA in 4 of 20 patients with widely metastatic adenocarcinoma and in 3 of 12 patients with a history of colorectal carcinoma in the adjuvant setting. None of the patients had detectable preexisting CEA antibodies. CEA specificity of the antisera was confirmed by competitive inhibition analysis as well as by recognition of baculovirus rCEA and human rCEA by Western blot. The humoral responses to CEA were predominantly IgG1 autoantibodies, with a minority of patients also demonstrating IgM autoantibodies.
We previously reported the absence of CEA antibody responses among the 20 patients with widely metastatic adenocarcinoma vaccinated with rV-CEA on protocol UAB 9619 (16) . Two important changes in the ELISA protocol led to the subsequent identification of CEA antibodies in patient sera that previously tested negative. The first modification was coating the ELISA plate with rCEA instead of native human CEA purified from human colon cancer liver metastases, which significantly reduced the background absorbance. The second modification was to incubate patient antisera in the ELISA plate overnight (instead of a 1-h incubation) to allow equilibrium to occur between the binding of CEA antibodies to solid-phase CEA on the plate and soluble CEA present in many patients’ sera. Both modifications combine to increase the sensitivity of the ELISA, especially for detection of low titer and low avidity CEA autoantibodies.
The observation that CEA antibodies detected in our patients were of
low titer and low avidity is supported by data from competitive
inhibition assays (Table 1)
. Several considerations relevant to all
circulating tumor-associated self-antigens may explain these results.
First, the inability to effectively boost with rV-CEA due to viral
neutralizing immune responses limits anti-CEA affinity maturation and
lymphocyte expansion. Secondly, circulating antigen (i.e.,
CEA) defeats affinity maturation by removing the selective pressure
that favors high avidity antibodies. Third, self-proteins like CEA are
inherently poorly immunogenic. Finally, any high avidity antibodies
that are produced are likely to be cleared from the circulation as
immune complexes with soluble CEA or through binding to solid-phase CEA
in normal or neoplastic tissues. The autoantibody that does circulate
is therefore likely to be of relatively low affinity and exist in
equilibrium between free antibody and immune complexes with circulating
antigen. Thus, the question arises as to what extent elevated serum CEA
levels frequently encountered in patients with advanced adenocarcinoma
adversely affect the ability to detect circulating anti-CEA
autoantibodies. We examined this issue by adding varying concentrations
of human CEA protein to relatively low titer, low avidity, polyclonal
monkey anti-CEA sera selected to approximate patient anti-CEA sera.
Significant inhibition of antibody detection was only observed at
extremely high serum CEA concentrations not encountered in patients,
i.e., greater than 10,000 ng/ml. In contrast, serum CEA
concentrations occasionally encountered in the clinic (i.e.,
approximately 1,000 ng/ml) significantly inhibited ELISA detection of
an anti-CEA monoclonal antibody. Thus, whereas clinically relevant
concentrations of serum CEA can competitively inhibit binding of a high
affinity monoclonal antibody to solid-phase CEA, inhibition of
relatively low affinity polyclonal antisera only occurs at enormous
serum CEA concentrations not seen in patients. This conclusion is also
supported by the fact that competitive inhibition of patient anti-CEA
sera binding to solid-phase CEA was observed with soluble CEA at 3 x 106 ng/ml sera but not at 3,000 ng/ml sera.
Another long-debated issue raised by the induction of anti-CEA autoantibodies is the potential influence of such antibodies on the ability to use serum CEA levels as a clinical indicator of disease progression or response (26) . The CEA antibodies induced in our patients did not affect quantitation of exogenous human CEA added to these sera, suggesting that this may not be a major issue.
As reported previously, no evidence of autoimmune toxicity was observed among patients vaccinated with rV-CEA in these trials, despite the production of circulating autoantibodies (16) . The low titer, low avidity, anti-CEA antibodies induced in the pilot Phase I/II trials reported here would likely have modest biological activity. Also, the incidence of anti-CEA antibody responses was low (7 of 32 patients). Thus, additional Phase I/II trials of rV-CEA priming followed by alternative booster immunization strategies with recombinant canarypox, plasmid DNA, or recombinant protein are warranted in an effort to increase the frequency and avidity of anti-CEA antibody responses as well as CEA-specific T-cell responses before Phase III trials.
|
ACKNOWLEDGMENTS |
|---|
|
FOOTNOTES |
|---|
1 Supported in part by NIH National Cancer
Institute Grant U01 CA61397-07. 
2 To whom requests for reprints should be
addressed, at Department of Medicine, Division of Hematology/Oncology,
University of Alabama at Birmingham, Comprehensive Cancer Center, 1824
6th Avenue South, L. B. Wallace Tumor Institute 263, Birmingham,
AL 35294-3300. Phone: (205) 934-7167; Fax: (205) 934-1608; E-mail: Marty.Conry{at}ccc.uab.edu
3 The abbreviations used are: CEA,
carcinoembryonic antigen; rV-CEA, recombinant vaccinia-CEA; NCI,
National Cancer Institute; pfu, plaque-forming unit(s); rCEA,
recombinant CEA; HRP, horseradish peroxidase.
Received 9/16/99; revised 10/11/99; accepted 10/12/99.
|
REFERENCES |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
This article has been cited by other articles:
|
|
 |
|
  S. Mosolits, G. Ullenhag, and H. Mellstedt Therapeutic vaccination in patients with gastrointestinal malignancies. A review of immunological and clinical results Ann. Onc., June 1, 2005; 16(6): 847 - 862. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. J. Ullenhag, J.-E. Frodin, M. Jeddi-Tehrani, K. Strigard, E. Eriksson, A. Samanci, A. Choudhury, B. Nilsson, E. D. Rossmann, S. Mosolits, et al. Durable Carcinoembryonic Antigen (CEA)-Specific Humoral and Cellular Immune Responses in Colorectal Carcinoma Patients Vaccinated with Recombinant CEA and Granulocyte/Macrophage Colony-Stimulating Factor Clin. Cancer Res., May 15, 2004; 10(10): 3273 - 3281. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. L Smith, N. Dulphy, M. Salio, and V. Cerundolo Immunotherapy of colorectal cancer Br. Med. Bull., December 1, 2002; 64(1): 181 - 200. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. H Palmer, M.-J. Chen, and D. J Kerr Gene therapy for colorectal cancer Br. Med. Bull., December 1, 2002; 64(1): 201 - 225. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. M. Conry, D. T. Curiel, T. V. Strong, S. E. Moore, K. O. Allen, D. L. Barlow, D. R. Shaw, and A. F. LoBuglio Safety and Immunogenicity of a DNA Vaccine Encoding Carcinoembryonic Antigen and Hepatitis B Surface Antigen in Colorectal Carcinoma Patients Clin. Cancer Res., September 1, 2002; 8(9): 2782 - 2787. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. L. Berinstein Carcinoembryonic Antigen as a Target for Therapeutic Anticancer Vaccines: A Review J. Clin. Oncol., April 15, 2002; 20(8): 2197 - 2207. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. J. Ullenhag, J.-E. Frodin, K. Strigard, H. Mellstedt, and C. G. M. Magnusson Induction of IgG Subclass Responses in Colorectal Carcinoma Patients Vaccinated with Recombinant Carcinoembryonic Antigen Cancer Res., March 1, 2002; 62(5): 1364 - 1369. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Hu, J. Lee, J. A. McCart, H. Xu, B. Moss, H. R. Alexander, and D. L. Bartlett Yaba-Like Disease Virus: an Alternative Replicating Poxvirus Vector for Cancer Gene Therapy J. Virol., November 1, 2001; 75(21): 10300 - 10308. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Gorschluter, C. Ziske, A. Glasmacher, and I. G. H. Schmidt-Wolf Current Clinical and Laboratory Strategies to Augment the Efficacy of Immunotherapy in Multiple Myeloma Clin. Cancer Res., August 1, 2001; 7(8): 2195 - 2204. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. L. Yip, G. Smith, J. Koch, S. Dubel, and R. L. Ward Identification of Epitope Regions Recognized by Tumor Inhibitory and Stimulatory Anti-ErbB-2 Monoclonal Antibodies: Implications for Vaccine Design J. Immunol., April 15, 2001; 166(8): 5271 - 5278. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Cancer Research | Clinical Cancer Research |
| Cancer Epidemiology Biomarkers & Prevention | Molecular Cancer Therapeutics |
| Molecular Cancer Research | Cancer Prevention Research |
| Cancer Prevention Journals Portal | Cancer Reviews Online |
| Annual Meeting Education Book | Meeting Abstracts Online |
