Ten
weeks after conception, the baby's heart beat can be heard
The
Chickenpox, Hepatitis-A and MMR vaccines were developed using aborted fetal
cell lines, MRC-5 and WI-38. This has never been hidden from the
public. When parents take their children to the doctor for inoculations, who
asks for the package inserts? Who asks for a list of the vaccine
ingredients? Most parents want to know the risks
and possible side effects. Parents are mostly concerned with the health of
their children as some doctors are. Doctors have been administering the
vaccines for years. Yet, how many of them have ever checked into the
ingredients? This has always been right at their fingertips. What would
happen if they did? They would read that the vaccine contains "MRC-5",
"WI-38" (or both) "human diploid cell lines".
Most parents
are not aware that the particular abortions which contribute the fetal
tissue parts for vaccine manufacturing, were actually intended for vaccine
manufacturing.
One
if the most highly misunderstood notions among moral theologians and
ethicists is that the abortions involved were not done with the intention of
creating vaccines. In fact, in response to President Bush’s decision on
federal funding for embryonic stem cell research (ESCR), the USCCB
highlights this point as follows:
“In the present case, human lives were taken in order to provide cells
for research and, in some cases, precisely to qualify for federal grants; in
the case of vaccines, tissues were taken following abortions performed for
unrelated reasons.” -(The NCCB
Secretariat for Pro-Life Activities, Vol. 12, No. 4 Aug-Sept 2001, The
Human Embryo as Research Commodity Special Edition)
It was the intent of the abortionist and the researcher to destroy these
babies specifically for vaccine manufacturing. But first, the abortions had
to be pre-arranged so the researchers were available to immediately preserve
the tissues.
"In order to sustain 96% of the cells, the live tissue would need to be
preserved within 5 minutes of the abortion"-Dr.
C. Ward Kischer
..."Within one the cells would continue to deteriorate, rendering the
specimens useless."
-[Dr. C. Ward Kischer,
Embryologist and Emeritus Professor of Anatomy; Specialist in Human
Embryology,
University of Arizona College of Medicine (Tucson, Arizona) Personal
interview 7-02, ALL Conference]
1961
Leonard Hayflick, employed by the Wistar Institute, research facility of
University of Pennsylvania, started working with aborted fetal cell lines
(WI-I through WI-25). Cell strains were derived from the lung, skin,
muscle, kidney, heart, thyroid, thymus and liver of 19 separate abortions.
The entire research was was for the development of viral vaccine
cultivation.
"The isolation of characterization of human diploid cell strains from fetal
tissue make this type of cell available as a substrate for the production of
live virus vaccines. Other than the economic advantages, such strains in
contrast to heteropoloid cells lines exhibit those characteristics usually
reserved for normal or primary cells and therefore make the consideration of
their use in the production of human virus vaccines a distinct possibility"-(L.
Hayflick and P.S.Moorhead, The Serial Cultivation of Human Diploid Cell
Strains, Experimental Cell Research, 1961, 25, pg 618)
1964
Hayflick isolates and gives name to the WI-38 cell line derived from the
lungs of a baby girl 3 months gestation.
"This fetus was chosen by Dr. Sven Gard, specifically for this purpose.
Both parents are known, and unfortunately, for the story, they are married
to each other, still alive and well, and living in Stockholm, presumably.
The abortion was done because they felt they had too many children. There
were no familial diseases in the history of either parents, and no history
of cancer specifically in the families."
-G. Sven, S. Plotkin, K.
McCarthy, Gamma Globulin Prophylaxis; Inactivated Rubella Virus;
Production and Biological Control of Live Attenuated Rubella Virus Vaccines;
Amer J Dis Child Vol 118 Aug 1969
"One of my duties as a young student in the laboratory in, Stockholm was to
dissect human fetuses from legal abortions and send organs to the Wistar
Institute. Such material was the source of many important studies of cell
lines of the Institute, such as Leonard Hayflick's study of WI-38"
-Norrby,
Erling "Listen to the Music: The Life of Hilary Koprowski (review)",
Perspectives in Biology and Medicine - Volume 44, Number 2, Spring 2001, pp.
304-306
Preying on the fear that 20%-25% of pregnant
women infected with Rubella pass it to their unborn children, possibly
causing defects, doctors encouraged pregnant women to have their unborn
children aborted during the 1964 epidemic. The first 26 aborted babies
were unaffected. The live rubella virus was found in the 27th killed
unborn baby.
"Explant cultures were made
of the dissected organs of a particular fetus aborted because of rubella,
the 27th in our series of fetuses aborted. This fetus was from a
25-year-old mother exposed to rubella 8 days after her last menstrual
period. 16 days later she developed rubella. The fetus was surgically
aborted 17 days after maternal illness and dissected immediately. Explants
from several organs were cultured and successful cell growth was achieved
from lung, skin, and kidney. It was then grown on WI-38,. The new vaccine
was tested on orphans in Philadelphia"
-American
Journal Diseases of Children; Virus Production and Biological Control of
Live Attenuated Rubella Virus Vaccines, Vol. 118 Aug 1969;
Attenuation Of RA273 Rubella Virus; Studies of Immunization With Living
Rubella Virus; Arch J Dis Child vol 110 Oct 1965
Rubella is
clinically named: RA273 (R=Rubella, A=Abortus, 27=27th fetus, 3=3rd tissue
explant) cultivated on WI-38 cell line.
Thus, at least
47 separate abortions involved in the research for production of present day
rubella vaccine.
Aborted Fetal Cell Line Vaccines And The
Catholic Family
Dr. Ron Paul On the
Bogus Swine Flu Vaccination
Swine Flu Exposé
(a free online book written
from the first Swine Flu scare in 1977, exposing the
lie of the Swine
Flue epidemic)
Brutal Murder
and dissection of the unborn:
"The Fetus As
Transplant Donor the Scientific, Social, and Ethical Perspectives," written
by Peter McCullough, who is an immunologist at the University of Western
Australia. It's published by the John Wiley Company in New York.
Here's McCullough. The
Australian International University in Canberra. This is the face page of
the book, and he probably knows more about the subject of using fetal tissue
than anybody in the world. Incidentally, he is pro-life, and it's remarkable
that his book delineates some of the technologies which have formerly been
used to get fetal brain tissue. For example, he talks about how in Sweden
they have been puncturing the sac of a pregnant woman at let us say 14 to 16
weeks, and then they put a clamp on the head of the baby, pull the head down
into the neck of the womb, drill a hole into the baby's head, and then put a
suction machine into the brain and suck out the brain cells.
And this is directly from
his book. Healthy human fetuses from 7 to 21 weeks from legal abortions
were used. This is in Sweden. The conceptional age was estimated from crown
rump length and so on. Fetal liver and kidney were rapidly removed and
weighed. Now at 21 weeks, what they were doing, or 18 weeks, or 16 weeks,
was what are called prostaglandin abortions. They would inject a substance
into the womb. The woman would then go into mini-labor and pass this baby.
50% of the time, the baby would be born alive, but that didn't stop them.
They would just simply open up the abdomen of the baby with no anesthesia,
and take out the liver and kidneys.
Debi Vinnedge,
Director of Children of God For Life (www.cogforlife.org)
is politically active. Please visit the organization's site to keep up to
date and find out your President's stand on the issue, along with her
correspondence with the manufacturing companies.
|
U.S. Vaccines Derived from Abortion |
|
Diseases |
Vaccine
|
Manufacturer |
Cell line (human fetal) |
|
Polio |
Poliovax |
Aventis-Pasteur |
MRC-5 |
|
Measles, Mumps, Rubella |
MMR II |
Merck & Co. |
RA273 and
WI-38 |
|
Measles-Rubella |
Biavax II |
Merck & Co. |
RA 273 and
WI-38 |
|
Rubella only |
MR-VAX |
Merck & Co. |
RA 273 and
WI-38 |
|
Rabies |
Imovax |
Vantis-Pasteur |
MRC-5 |
|
Hepatitis A |
Hivrax
Vaqta |
AlaxoSmithKline
Merck & Co. |
MRC-5
MRC-5 |
|
Hepatitis A-B combo |
Twinrix |
GlaxoSmithKline |
MRC-5 |
|
Chickenpox |
Varixax |
Merck & Co. |
WI-38 and
MRC-5 |
|
Smallpox |
Acambix 1000 |
Acambis |
MRC-5 |
|
Ebola |
Unknown (still waiting for
trial) |
Crucell & N.I.H. |
PER C6 |
|
HIV |
Unknown (still waiting for
trial) |
Merck & Co. |
PER C6 |
|
Sepsis |
Xigris |
Eli Lilley |
HEK 293 |
|
Influenza (flu) |
unknown |
MedImmune |
PER C6 |
About Xigris...
[Published 28 August 2002 Source Espicom Business
Intelligence]
Xigris received approval from the FDA on 21st November 2001 for the
reduction of mortality in adult patients with severe sepsis who have a high
risk of death. Xigris has also been approved in Puerto Rico, Israel,
Australia, Argentina, Peru, Romania, Columbia, Mexico, Switzerland, India,
Singapore and South Africa.
Xigris is a genetically-engineered version of the human activated protein C
molecule, a naturally-occurring protein in the body that helps to balance
many of the forces behind sepsis, including coagulation and
suppression of fibrinolysis. Additionally, patients with severe sepsis
treated with Xigris had a more rapid decline in interleukin-6 levels,
consistent with a reduction in the inflammatory response. The drug is
administered to patients as a 1-time, 96-hour infusion within an ICU
setting. The precise dosage depends on the weight of the patient. In the
PROWESS trial, bleeding was the most common adverse reaction associated with
Xigris therapy. Serious bleeding events, including intracranial haemorrhage
(0.2 per cent in Xigris-treated patients and 0.1 per cent in placebo-treated
patients), were observed during the 28-day study period in 3.5 per cent of
Xigris-treated patients and 2.0 per cent of placebo-treated patients. The
difference in serious bleeding occurred
primarily during infusion.
A human cell line is used in the production of Xigris, as noted under FDA
document, PC 3420 AMP, in the first paragraph, which states:
“Xigris is a recombinant
form of human activated protein C. An established human cell line
possessing the complementary DNA for the inactive human protein C zymogen
secretes the protein into the fermentation medium.”
HEK 293 are cells taken from the kidney of an
aborted baby.
About the 293 Cell Line...
The protein C is produced in the HEK 293 aborted
fetal cell line. 293 cells are available from the American Type Culture
Collection. There are variants of the cell
line that derive from the parent.
ATCC Number: CRL-1573
Price: $167.00
Designation: 293 Depositors: F.L. Graham
Biosafety Level: 2 Shipped: frozen
Organism: Homo sapiens (human) Morphology: epithelial
Tissue: kidney; transformed with adenovirus 5 DNA
The 293 cell line is a
permanent line of primary human embryonal kidney transformed by sheared
human adenovirus type 5 (Ad 5)DNA. [RF32725]
The cells express the
transforming gene of adenovirus 5. Although an earlier report suggested that
the cells contained Adenovirus 5 DNA from both the right and left ends of
the viral genome [RF32764], it is now clear that only left end sequences are
present. [RF50113]
The cells express an
unusual cell surface receptor for vitronectin composed of the integrin
beta-1 subunit and the vitronectin receptor alpha-v subunit. [RF33793]
Purified DNA from this line is available as ATCC 45504 (25 micrograms) and
ATCC 45505 (100 micrograms).
The Ad5 insert was cloned
and sequenced, and it was determined that a colinear seqment from nts 1 to
4344 is integrated into chromosome 19
(19q13.2). [RF50113]
United States Patent
5,681,932
Grinnell October 28, 1997
Inventors: Grinnell; Brian W. (Indianapolis, IN)
Assignee: Eli Lilly and Company (Indianapolis, IN)
Application No.: 458372
Filed: June 2, 1995
1.
The recombinant human protein C molecule produced by inserting a vector
comprising the DNA encoding human protein C into an adenovirus-transformed
host cell then culturing said host cell under growth conditions suitable for
production of said recombinant human protein C.
2. The recombinant human protein C molecule
of claim 1 wherein the adenovirus-transformed host cell is selected from the
group consisting of AV12 cells and human embryonic kidney 293 cells.
3. The recombinant human protein C molecule
of claim 2 wherein the adenovirus-transformed host cell is an AV12 cell.
4. The recombinant human protein C molecule
of claim 2 wherein the adenovirus transformed host cell is a human embryonic
kidney 293 cell.
About the 293 Abortion...
In the FDA report found at
http://www.fda.gov/ohrms/dockets/ac/01/transcripts/3750t1_01.pdf
Key statement...Page 81 lines 14-22
"So the Kidney material, the fetal kidney
material was as follows. The kidney of the fetus was, with an unknown
family history, was obtained in 1972 probably. The precise date is not
known anymore.
The fetus, as far as I can remember was
completely normal. Nothing was wrong. The reasons for the abortion were
unknown to me. I probably knew it at the time, but it got lost, all this
information."
About the PER C6 Abortion and cell
lines....
http://www.fda.gov/ohrms/dockets/ac/01/transcripts/3750t1_01.pdf
Key excerpts from the above document: Dr. Van
Der Eb, Crucel NV is speaking...
"So I isolated retina from a fetus, from a
healthy fetus as far as could be seen, of 18 weeks old. There was nothing
special with a family history or the pregnancy was completely normal up to
the 18 weeks, and it turned out to be a socially indicated abortus - abortus
provocatus, and that was simply because the woman wanted to get rid of the
fetus."
"The father was
not known not to the hospital anymore, what was written down was unknown
father, and that was, in fact, the reason why the abortion was requested."
"There was permission, et cetera, and that
was, however, was in 1985, ten years before this. This shows that the cells
were isolated in October 1985, Laeiden University in my lab. At that time
already '85, I should say the cells were frozen, stored in liquid nitrogen,
and in 1995 one of these was thawed for the generation of the PER.C6 cells.
"And this is the final slide just showing you
some comparisons between 293 and PER.C6. Again, I remind you that both
cell lines were made in my lab for different reasons. The objective, as I
indicated, is for 293--was basic research, and we have done many different
transformation studies after that, not transformation studies, but gene
expressions studies with human embryonic kidney cells in the years following
that up to now, I would say.
"PER
C6 was made JUST FOR PHARMACEUTICAL MANUFACTURING OF ADENOVIRUS VECTORS
As to RCA
free, PER.C6 are RCA Free. The history documentation of the cell line has
been carried out completely for PER. C6 and was not done at that time for
293.
"And then pharmaceutical
industry standards... I realize that this sounds a bit commercial, but PER
C6 were made for that particular purpose."
About the Cell Lines and Adenovirus (AD5) Safety issues...
http://www.fda.gov/ohrms/dockets/ac/01/briefing/3750b1_01.htm
Background
In 1954, during discussions surrounding the
development of adenovirus vaccines for use in the military, the U.S. Armed
Forces Epidemiology Board (AFEB) recommended the use of "normal cells" as
the substrate for vaccine production rather than cell lines established from
human tumors. This decision was based on concerns about the possibility that
human tumor cells might be contaminated with occult oncogenic agents that
might be transferred to vaccine recipients, an event which might in turn
increase the risk of cancer and other neoplastic diseases in vaccinees. As
evidenced by current regulatory guidelines and activities of control
authorities worldwide, the precedent set in 1954 by the AFEB remains an
important factor in the acceptance of all substrates for vaccine
manufacture. Currently, the only cultured animal cells that have been used
as substrates in U.S. licensed viral vaccines have been primary cells (e.g.,
derived from monkey, chick, mouse), diploid cell lines (e.g., WI38, MRC-5,
FRhL-2), or immortalized (continuous), non-tumorigenic cell lines (e.g.,
VERO).
Over the past 47 years, two important factors
have emerged that warrant serious consideration of the use of immortalized
tumorigenic cell lines for viral vaccine production. The first of these
factors is that certain novel virus vectors that are presently under
development for high-priority target diseases, most notably AIDS, cannot
feasibly be propagated in
traditionally acceptable cell substrates. The
second factor is that scientific understanding of neoplastic processes and
viral-induced carcinogenesis has rapidly advanced, as has the ability to
detect and identify infectious, oncogenic agents and other types of
adventitious agents that may potentially contaminate cell substrates. These
factors underscore the need for developing a regulatory framework in which
the relative benefits and risks in using tumorigenic cell lines for vaccine
production can be carefully and cautiously revisited.
FDA would like the VRBPAC to consider the
potential risks in using two novel cell substrates, 293 cells and PER.C6
cells. These cell lines were developed by transforming human embryonic
kidney cells (293) and human embryonic retinal cells (PER.C6) with the
transforming early region 1 (E1) of adenovirus type 5 (Ad5). Since cell
lines such as 293 and PER.C6 express the Ad5 E1 region, they are able to
complement the growth of defective Ad5 vectors which have been "crippled" by
deletion of E1. Defective Ad5 vectors have been engineered to express
foreign genes such as those from human immunodeficiency virus (HIV), the
causative agent of AIDS, and vectors of this type are thought to have
significant potential for vaccine development because of their demonstrated
ability to generate cell-mediated immune responses to HIV. However, a
feature of regulatory importance associated with Ad5-transformed cells is
their capacity to form tumors in immunodeficient animals such as nude mice.
In considering potential risks associated with
the use of these so-called Designer Cell Substrates – i.e.,
neoplastic cells derived from normal human cells transformed by defined
viral or cellular oncogenes or by immortalizing cellular genes (e.g.,
telomerase) – OVRR/CBER is considering the approach outlined below within
the framework of a "defined-risks" assessment (see enclosed reference Lewis
et al., "A defined-risks approach to the regulatory assessment of the
use of neoplastic cells as substrates for viral vaccine manufacture", In
Evolving Scientific and Regulatory Perspectives on Cell Substrates for
Vaccine Development. Brown, Lewis, Peden, Krause (eds.) Develop. Biol.
Stand. [in press]). This framework is intended to examine, and wherever
possible, to quantify the potential risk of "transmitting" the tumorigenic
components of the cell substrate used for vaccine production, and determine
whether that "transmission" might pose a risk, particularly an oncogenic
risk, to vaccinees. Factors that could influence the risk associated with
the use of Designer Cell Substrates include (1) the known mechanism of cell
transformation leading to the development of tumorigenic cells; (2) residual
cell substrate DNA; and (3) the presence of adventitious agents, especially
oncogenic viruses. These three factors are discussed in more detail below.
Tumorigenicity of Adenovirus 5-Transformed
Designer Cell Substrates
The purpose of tumorigenicity testing as
applied to cell substrates used for viral vaccine manufacture is to
discriminate between cells that have the capacity to form tumors and cells
that do not form tumors. The potential risk of oncogenic activity is thought
to be higher for cell substrates that have the capacity to form tumors,
whereas the potential risk is thought to be low for cell substrates that are
unable to form tumors. In considering the risk of tumorigenicity of
Ad5-transformed Designer Cell Substrates, it is important to consider the
molecular processes that determine the ability of the cells to form tumors.
Adenovirus 5 does not produce tumors when
injected into rodents, but it does transform rodent cells in tissue culture.
Like adenovirus 5 virions, adenovirus 5-transformed cells do not produce
tumors when injected into immunocompetent adult rodents, but these cells can
form tumors when injected into immunodeficient rodents such as nude mice.
The tumor-forming capacity of Designer Cell Substrates that are produced by
transforming normal human cells with adenovirus 5 can be evaluated by
comparing them with adenovirus 5-transformed rodent cells. The adenovirus 5
early region 1 (E1) is composed of the transcription units E1A and E1B,
which transform normal cells to neoplastic cells through a multi-step
process. The E1A transcription unit immortalizes the cells and establishes
those characteristics of the transformed cells that permit them to be
eliminated by the antitumor defenses of immunocompetent rodents. During the
transformation process, E1A sensitizes cells to apoptosis (programmed cell
death) and increases their susceptibility to killing by natural killer
cells, macrophages, and cytotoxic lymphocytes, as well as cytokines such as
tumor necrosis factor (see Routes et al., 2000a, 2000b). The
adenovirus E1B region alone is unable to immortalize cells, but its function
during neoplastic transformation ensures cell survival by inhibiting
virus-induced cell killing. Thus, the E1A region immortalizes cells and
determines their limited capacity to form tumors in immunodeficient rodents,
whose antitumor immune defenses are compromised. The complexity of these
tumor-host processes and their action through nontransferable, immune
mechanisms of the host implies that the capacity of adenovirus 5
E1-transformed mammalian cells to form tumors in immunodeficient rodents
does not represent a risk factor for the manufacture of viral vaccines
provided the cells can be shown to be devoid of adventitious agents (see
additional discussion on adventitious agents below).
Several approaches can be considered in
evaluating tumorigenicity of adenovirus 5-transformed human cell substrates.
These approaches include demonstration that the tumor-forming capacity of
the cells in rodents is adenovirus 5-like, and that the cells in the master
cell bank are devoid of known and occult adventitious agents.
Potential Risks of DNA in Vaccines
Residual DNA in vaccines derived from
tumorigenic cells, including those transformed by Ad5, can pose potential
risks to the vaccine recipient in two respects: oncogenicity and
infectivity. Each of these biological properties must be considered and
evaluated for each cell substrate.
The oncogenic risk of cell substrate DNA has
been considered to be due to several mechanisms. First, the residual DNA
could have dominant activated oncogenes that could exert their effect
following expression in recipient cells. In the case of Ad5-transformed
cells, the dominant oncogenes would include the E1A and E1B genes. Second,
the incoming DNA could integrate into the host genome in certain genes, such
as the p53 gene or the retinoblastoma susceptibility (RB) gene, termed tumor
suppressor genes, which are involved in cell cycle control among other
cellular processes. Loss of function of tumor suppressor genes has been
associated with certain human tumors. Third, integration of residual
cell-substrate DNA could result in the activation of cellular regulatory
genes by promoter/enhancer insertion, and this could result in the
development of a neoplastic phenotype; this mechanism for tumor development
was initially described in chickens for leukemia formation by avian leukosis
viruses. Another result of integration that has been described is an
increased methylation of adjacent DNA sequences as well as sequences on
other chromosomes, although the consequences of such changes in methylation
patterns to a cell are unknown.
The second biological activity of DNA that
should be considered is its potential infectivity. If a genome of a DNA
virus or the provirus of a retrovirus is present in the cell substrate used
for vaccine manufacture, then the residual DNA has the potential, upon
inoculation into the vaccine recipient, to produce infectious virus from
this DNA and thus establish a productive infection.
The assessment of the risk of DNA — both the
oncogenic risk and the infectious risk — needs to be considered both in
terms of (1) the amount of residual DNA inoculated; and (2) the
concentration of oncogene or infectious genome present in this DNA. One
assumption is that the biological activity of any DNA administered is
directly proportional to the amount of that DNA, and if the active component
(oncogene or infectious genome) is carried as part of the cell-substrate
DNA, the amounts of the oncogene or infectious genome will be present at a
level of 10-5 to 10-6. This is because the haploid
mammalian genome is 3 x 109 base pairs, whereas an average gene
is between 3 x 103 and 104 base pairs. Thus, if the
residual DNA is present at 10 ng, an oncogene in that DNA would be present
at between 0.00001 and 0.0001 ng. Currently there are no data indicating
that purified isolated oncogenes or any other DNA are biologically active at
these levels.
It is also important to note that an
additional safety margin for oncogenic activity is provided by the
multi-step nature of cancer. This is because if more than one gene or event
is required, the risk is diminished and is given by the product of the risk
for each event. Thus, if the risk of a neoplastic event being induced by one
oncogene is 1 in 106, then if two oncogenes are required, the
risk is reduced to 1 in 1012.
Strategies that can be considered in
evaluating residual DNA for vaccine products manufactured in adenovirus
5-transformed cell substrates include restricting the level of residual DNA
to 10 ng or less. If these levels of residual DNA are not feasible, other
methods can be considered to demonstrate the safety of higher levels of DNA,
such as the inoculation of cell-substrate DNA into neonatal rodents. In the
future, more sensitive animal models and in vitro assays may be developed to
assess the oncogenic activity of DNA.
The experience in the early 1960s with SV40
contamination of poliovirus and adenovirus vaccines and the continuing
questions regarding whether SV40 could be responsible for some human
neoplasms underscore the importance of keeping viral vaccines free of
adventitious agents. This is particularly important when there is a
theoretical potential for contamination of a vaccine with viruses that might
be associated with neoplasia.
It is unclear whether neoplastic cells have a
greater or lower adventitious agent risk than other types of cells. Because
they can be grown for long periods in tissue culture, there may be greater
opportunities for any adventitious agents to be detected. Because neoplastic
cells survive indefinitely, it is easier to qualify and bank cells that have
passed all tests, especially as compared with primary cells (which are
derived repeatedly from live tissue and must be re-qualified with each use).
Moreover, many neoplastic cells can be grown in serum-free medium,
potentially reducing the likelihood of contamination with bovine
adventitious agents. However, if their growth in tissue culture is not well
controlled, there may exist additional opportunities for contamination of
cells with a longer lifespan. In cases of neoplastic cells for which the
transforming event is unknown, there is also a theoretical possibility that
transformation occurred as a result of a previous viral infection. Because
some mammalian tumors and some cells transformed by viruses contain
infectious virus, cells transformed by an unknown mechanism have a
theoretical risk of containing a transforming virus. Cells for which
specific knowledge of the transforming event exists (and can be shown not to
be a virus that persists in the cells) may be more easily characterized than
cells for which there is no specific knowledge of the transforming event
(which could theoretically have been due to an infection with a known or an
unknown virus).
Extensive adventitious agent testing is
required for all cells that are proposed for use in vaccine production. This
includes testing in various tissue culture systems, inoculation of animals
followed by observation or detection of pathogen-specific antibodies,
observation by electron microscopy, and molecular tests as is appropriate
based on the history and type of cell to be tested. Specific polymerase
chain reaction assays are used to rule out the presence of many different
viruses. PCR-based reverse transcriptase assays are used to rule out the
presence of retroviruses. The most sensitive of these assays include
amplification steps, either as a result of viral growth in culture or in an
organism, or molecular amplification such as in PCR.
Although Ad5-transformed cells are thought to
be transformed by a known mechanism, the consequences of overlooking an
occult oncogenic agent are significant. As these are the first cells in
their class to be considered for vaccine production, evaluating them for the
presence of occult oncogenic agents could enhance confidence in their use.
One relevant animal assay that could be used for such an evaluation is the
inoculation of cell-free lysates into susceptible newborn rodents, followed
by observation for 5-6 months. This assay would detect most known tumor
viruses, as well as potentially detect unknown tumor viruses.
Several promising areas of research suggest
that experimental assays to detect unknown adventitious agents could soon
become more generally available. As such assays become available, they could
be considered for use in qualifying novel cell substrates, including
neoplastic cell substrates.
Risk of Transmissible Spongiform
Encephalopathy (TSE)
In addition to assessing the possibility of contamination
of cell substrates with infectious virus, it is important to consider other
agents such as the agent of TSE. There are several mechanisms by which
vaccine cell substrates, including neoplastic cells, could theoretically
become infected with a TSE agent. First, viral vaccines are developed and
manufactured in cell substrates that may be derived from humans, and all
human cells represent a finite possibility of being derived from individuals
with a propensity to develop sporadic or familial Creutzfeld-Jakob disease
(CJD). Although the mechanism by which such individuals develop CJD is not
understood, CJD has in the past been transmitted to humans by biological
products derived from CJD patients, such as human growth hormone and dura
mater grafts. Second, vaccine cell substrates are usually exposed to
products derived from cattle during tissue culture. Bovine spongiform
encephalopathy (BSE) has been transmitted to humans in Europe in the form of
variant CJD, possibly due to ingestion of infected beef. Under certain
circumstances, cells in tissue culture can support the replication of
certain TSE agents, although it is not known whether human cells in
tissue culture can sustain the replication of the BSE agent. Assays
to detect TSE/BSE agent contamination exist, but they may not be sensitive
enough to exclude low levels of contamination. Until more is known about the
replication of TSE/BSE agents in tissue culture and until more sensitive
assays to detect these agents become available,
the concern over the possible
contamination of viral vaccines with TSE/BSE agents will be at least a
theoretical consideration in vaccine
development.
The use of immortalized, neoplastic human
cells as substrates to develop recombinant viral vectors as vaccines also
raises theoretical concerns with regard to possible contamination with TSE/BSE
agents. These concerns include: (1) the implications of the possible
presence of a prion protein (PrP)-encoding gene (PRNP) that is abnormal in
the individual from whom the cells were derived; (2) the possibility that
the genomic instability attendant with neoplastic processes could produce
pathogenic alterations in the normal PRNP gene; (3) the possible exposure to
agents of BSE present in bovine serum used in the propagation of the cells;
(4) the possibility that an increased level of expression of either a normal
or abnormal PRNP gene or other unknown factors in neoplastic cells might,
upon exposure, sustain the replication of abnormal PrP proteins or otherwise
contribute to the development of TSE in humans; and (5) the possibility that
differences in the levels of expression of PRNP genes among clonal/subclonal
populations of neoplastic cells may make evaluation of these potential risks
more difficult. Since the lifetime risk of sporadic TSE in the population is
about one case per ten thousand people (see Brown, P. et al., [1985],
Potential epidemic of Creutzfeldt-Jakob disease from human growth hormone
therapy. N Engl J Med. 1985, 313:728-731), there is a finite risk that
random tissue samples used for the development of neoplastic cell lines
could contain abnormalities that might be associated with TSE transmission.
Several strategies can be considered for
evaluation of neoplastic human cells for possible contamination with TSE/BSE
agents. These strategies include a determination of the origin of the cells
with respect to the possible family history and medical history of the donor
regarding TSE risk factors and the identification and documentation of
possible exposure of the cell line to bovine-derived materials, such as
fetal bovine serum from countries with BSE. Further, two validated methods
that could be used to evaluate the potential risk from the TSE agent include
sequencing of the PRNP gene from neoplastic cell substrates and evaluating
all such cell substrates by Western blot for the presence of protease
resistant PrP. Additional studies may become feasible in the near future and
may include evaluation of PRNP expression levels, determination of the
ability of a cell substrate to support replication of the BSE agent, and
evaluation of for the presence of infectious TSE agents by animal
inoculation. As new assays for the detection and evaluation of TSE agents
become available, they should be introduced as appropriate for cell
substrate screening.
OVRR/CBER plans to present these issues to the
FDA TSE Advisory Committee for a comprehensive discussion in the near
future. In the interim, for cell substrates for which the presence of TSE
could be a risk, sponsors should evaluate this issue by a combination of
strategies, as may be technically feasible. Nevertheless, OVRR/CBER would
like this Committee to be aware of and consider those issues related to the
possible presence or exposure of cell substrates used for the development of
viral vaccines to agents associated with TSE/BSE.
SUMMARY
Recent animal experiments have demonstrated
the utility of Ad5 vaccine vectors as means of stimulating cell-mediated
immunity against HIV-1. Based on the review of available data, OVRR/CBER
believes that there is an extremely low probability that residual DNA from
the adenovirus 5-transformed human cells could transfer traits that could
induce neoplastic development in vaccinees. OVRR/CBER also believes that
such cells may be considered for the development of HIV vaccines, provided
that the phenotype of the cells can be documented to be of an adenovirus 5
E1 type, and that appropriate testing rules out the presence of adventitious
agents within the limits of state-of-the-art technology.
For further details
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John 8:32,36, “And ye shall know the
truth, and the truth shall make you free ...
If the Son therefore shall make you free, ye shall be free
indeed.”
