PROFESSOR STEFAN S. NICOLAU (1896-1967)
A FOUNDER OF VIROLOGY IN ROMANIA*
“St. S. Nicolau “ Institute of Virology
285, sos Mihai Bravu, Bucharest 030304
firstname.lastname@example.org Abstract. Forty years have passed since Professor Stefan S. Nicolau deceased. He was the founder of the Institute
of Virology in to Romanian Academy’ structure. As assistant of outstanding scientist Constantin Levaditi (1874-1953), Nicolau was trained at the Pasteur Institute. Their collaboration was exceptionally fruitful, producing new
concepts in virology. Between their most cited contributions was the concept of viral oncolysis. Oncolytic viruses
are capable of selective replication in malignant cells and therefore offer levels of potency and specificity that are
potentially far higher than conventional treatments for tumour. Viral oncolytic therapy is to day under intense
investigation as a novel anticancer strategy, both alone and in combination with other conventional treatment
modalities. Nicolau was between the first to observe a possible analogy between viruses and gene, and hence to
anticipate the future importance of molecular biology. In Romania, it was in his Institute were people from
different specialities, biologists, biochemists, and doctors were debated the implications of genetic engineering
long before it was in practice possible that science fiction became fact, as the use of DNA synthesis, restriction
enzymes and plasmids.
Key words: Stefan S. Nicolau, ultravirus, viral oncolysis, Borna disease.
* In commemoration of 40 years since the time of Stefan S. Nicolau death
INTRODUCTION to isolate and cultivate as true microbes.
Levaditi and Nicolau coined the term of
In the history of virology, ultravirus instead the label of “filterable circumscribed to the first half of a viruses” or “invisible viruses”, the label twentieth century sequence, the th century in France used throughout the 19
contribution of Romanian scientists as a blanket term for new, unorthodox,
Constantin Levaditi and Stefan S. Nicolau infectious agents. In fact, Levaditi and
played an important role. As faithful Pierre Lepine published the first textbook
followers of Pasteur they assumed that of virology in 1938: “Les ultravirus des new filterable agents of infectious diseases 2maladies humaines”. It is to be noted that discovered by botanists (D.I. Ivanovski – the term “virology” became established in
Tobacco Mosaic Disease), by its own right only after the World War II
veterinarians (F. Loeffler, and P. Frosch – with the apparition of the S. E. Luria’s
foot and mouth disease) or by physicians classic manual “General Virology” (1953)
(W. Reed, and J. Carroll – yellow fever; K. and of the first issue of the journal 1Landsteiner, and C. Levaditi - Virology (1955).
poliomyelitis) were small bacteria unable
Fig.1. Jubilant “Nicolau” Medal awarded for excellence in PhD works at the Institute of
Virology, Bucharest (a craftwork of outstanding Romanian sculptor Ion Jalea).
Nicolau was a natural organizer and, relationships), Elena Oprescu (respirtory together with Radu Portocalã and Nicolae viral infections), Radu Portocala Cajal, he began to recruit people to work (biochemistry of the viral nucleic acids), on isolation and cultivation of human and Dan Sarateanu (ornithoses), Constantin animal viruses. He developed a group of Surdan (Rickettsia), Nicolae Cajal - his devotees and students who adopted his succesor at the Institute and Chair of view points on the important problems of virology direction. The Institute bridges virus diseases of humans and domesticated the gap between clinical investigation and animals in parallel with research in the application of basic science in order to theoretical and experimental virology. understand the pathogenesis of the
infectious diseases, their diagnosis and
Stefan S. Nicolau founded the optimal management, prevention and Institute of Inframicrobiology of the control. Romanian Academy. The Institute has its
origin in the nucleus of the Chair of SHORT BIOGRAPHIC NOTE Virology, which began its activity in 1942
Stefan S. Nicolau obtained in in the framework of the Faculty of
1920 the MD degree at the Faculty of Medicine in Bucharest. For the first time
Medicine in Cluj, where he began this in the world, in the higher medical
collaboration with professor Moldoveanu. education, a separate discipline was
From his student years in Cluj, Nicolau devoted to the study of the ultrafiltrable
showed his tendency towards laboratory infectious agents. Afterwards, a team of
research. After having spent one year in inframicrobiology of the Academy was
Cluj, he began to work at Levaditi’s created, which developed into the actual
laboratory in the Pasteur Institute. Nicolau “Nicolau” Institute of Virology. The
studied for two decades at The Pasteur ?Stefan S. Nicolau? Institute of Virology,
Institute in Paris (1920-1939). During this which chronologically is one of the first
interval he passed his PhD at Sorbonne institutions in this speciality in Europe,
(1925) and visited National Institute for has celebrated in 1999 the 50th
Medical Research – London (1927-1931). anniversary of its foundation. Many
He received many awards from Paris disciples of the school created by
Academy of Sciences and also important professor Nicolau distinguished
prizes: Prize Bellion, 1926, Prize Breant, themselves by significant contributions:
1930, Prize Montyon, 1935. Out of the Adelina Derevic (respiratory viral
country until 1939, Nicolau authored infections), Elisabeta Nastac (virus-cancer
7pioneering studies regarding viral diseases ; the introduction of arbovirus infection
34such as: herpesthe synchronophylaxis concept, a fact , rabies, poxvirus
5, 6which promotes him as a, precursor of the infections (especially vaccinia),
78interference phenomenon descriptionaphthous fever, Borna disease, ; the Aujeszky’s disease, ?looping illness? and discovery of the photodynamic action of
others. Among the worldwide stains (which is nowadays widely used in
acknowledged priorities we mention: the viral mutagenesis research on); the
9first detection of inclusions in the yellow description of the septic neuritis and fever – a diagnostic criterion of this others.
Fig 2. The office block of “Nicolau” Institute of Virology (www.virology.ro)
In 1939, Nicolau returned in Iasi Medical School, and in 1942, as
Romania as professor of Microbiology at professor of Inframicrobiology at
Bucharest Medical School. In the these objects by newly available electron recognition of his outstanding publications microscope in the early 1940’.
he was elected member of Romanian
In a broad prospective view of the Academy of Medical Sciences and of
pathogenesis of viral infections, Levaditi Romanian Academy.
and Nicolau underlined the cell-mediated He was director of the Institute of
character of the antiviral immunity. Beside Inframicrobiology in Bucharest (to day,
the viral cytocidal effect, Nicolau revealed “St. S. Nicolau” Institute of Virology),
the participation of the cellular immune where he have the opportunity to create
response of the host in the triggering of the many independent laboratories in which
symptomatology. his co-workers served national public
In a critical review of the literature health and medical school. As a teacher he on the antigenic propertiesof the was the editor of remarkable manuals
ultraviruses, Nicolau and co-workers translated in French, Russian, Chinese etc. 11 (1928) called attention to thefact that
these agents of disease, as far as they have EARLY WORKS been studied,seem to exhibit antigenic
In 1922, Levaditi and Nicolau properties which suggest placing themin
published a series of articles in which new the general group of bacteria and other properties of the viral agents were more highly organized proteinaceous
demonstrated: ultrafiltrability (passage bodies.They observed that vaccinia virus through the pores of a collodion inoculated into the brain of an immunized membrane), antigenic properties of killed rabbit could not be demonstrated two and replicative viruses etc. Nicolau and hours after the injection. While vaccinia Levaditi elaborated experiments on the virus persisted in the circulation of a filterability of viruses with a very original susceptible rabbit for as long as 8 days and more constructive interpretation. They following intravenous infection, it opposed to the concept of non-particulate disappeared from circulation of an infective organism. In the debate about immune rabbit within 4 to 6 hours. whether the viruses were living or Nicolau and Kopciowska made a similar nonliving, or perhaps were the primordial observation regarding herpes virus stuff from which life itself originated, introduced into the brain of immunized
7Nicolau underscored the macromolecular rabbits. nature of viruses and the significance of The same as the classic of Romanian their tiny component - the genomic nucleic medicine – Victor Babeº - Nicolau’ early
acid. The structure of viruses was soon research works were connected with rabies. amply confirmed by direct observation of He described extremely important lesions
in the central nervous system of animal Between the most cited Nicolau’ dead of rabies or of other neurotropic publications were papers referring the role
viruses. Although described by Victor of Borna virus infection in
Babeº as far back as 1886, the cytoplasmic neurobehavioural diseases. Borna disease inclusions in rabies were given the name virus (BDV) is the prototype of the family
11of “Negri bodies”. The priority of Babeº Bornaviridae, genus Bornavirus, within was recognized owing to the well the nonsegmented negative-strand
documented works of St. S. Nicolau and ribonucleic acid (RNA) viruses (order
Mircea Babeº. Nicolau was the editor of Mononegavirales). Nicolau and Galloway two volumes of V. Babeº selected works were the firsts to conduct experimental and of many monographs which created a study of Borna disease in sheep and cattle
true virology library in Romanian. (see and describe the characteristics of this
13books at the references) This enzootic encephalo-myelitis.
neurotropic virus appears to be distributed
In regard to the immunological worldwide and has the potential to infect conditions existing inherpes disease, his most, if not all, warm-blooded hosts. The
experiments have reaffirmed that herpes name Borna refers to the city of Borna, viruscan be neutralized with the serum of Germany, the site of an equine epidemic in actively immunized animalsand have 1895–1896 that crippled the Saxon cavalry. offered an explanation for the irregularity Natural infection has been reported of theresults of others. Nicolau et al. primarily in Europe, but recent reports found thatbrain extracts from inoculated also include North America and parts of
rabbits possess some virus-neutralizing Asia (Japan, Israel and Iran). Reports of power, but considerablyless than the asymptomatic, naturally infected animals
serum of the corresponding control suggest that the virus may be more animals. It hasbeen shown that active widespread than previously appreciated.
immunity can be attained only when someReports of BDV nucleic acid and proteins
degree of reaction to the living virus has in peripheral blood mononuclear cells also occurred. Rabbitswhich survived indicate a potential for haematogenous
neutralized serum-virus mixtures did not transmission.
acquireimmunity nor did those treated Although there is consensus that
with virus phenolized to theextent of humans are likely to be susceptible to
9actual destruction. BDV infection, the epidemiology and
clinical consequences of human infection
remain controversial. After 1990, German
THE MOST CITED WORKS scientists reported that Borna infectious
14, 15virus has been isolated from humans.
There have been no large controlled of general pathology. Thus, morphological prevalence studies but methods for data supported the viral etiology of some diagnosis of human infection were reliable cardiovascular diseases (arteritides,
21suggesting an association between BDV and the role of chlamydia, myocarditides)and neuropsychiatric disorders, including rickettsia and some herpesviruses in the unipolar depression, bipolar disorder or etiopathogenesis of some congenital schizophrenia. BDV has also been linked malformations and spontaneous
22 to chronic fatigue syndrome, abortions.
An innovative concept developed I shall detail my remarks to by Levaditi and Nicolau was viral Nicolau’ papers on the relations between oncolysis in studies where the viruses and cancer, published in the period
neurovaccinal virus was inoculated into from 1960 to 1967, which I personally
16grafted tumours. Sinkovics J.C., and consider highly significant. The author
17Horwath J. (Viruses and cancer. Medical summarises the general properties of Hypotheses 1995, 44, 359-368.) quoted human tumour viruses, reviews the from the paper of Romanian scientists: development of causal thinking in “Tumours are more susceptible to viruses microbiology and proposes guidelines that than normal cells and tumours act as a might help to determine the role of viruses sponge attracting viral replication". This in human cancer. The work on the role of hypothesis is now in the centre of interest viruses in the pathogenesis of human for many biotechnology companies who cancer was hampered by the fact that enlarge cancer virotherapy models. virus-associated cancer develops only in a
Stefan S. Nicolau made obvious small minority of infected subjects, which the theory of viral etiology of some implies that, if the virus does play a role in cancers. With a remarkable intuition the pathogenesis of the malignancy, other Nicolau promoted the hypothesis of the factors must be also involved. Naturally oncogenic potential of the viral nucleic oncolytic viruses are replication-acids. He developed the infravirus model – competent viruses that have an innate the autonomized form of viral nucleic ability to selectively infect and kill tumour acids which, after its integration in the cells. Despite being used in the original host cell genome, contribute to the viral attempts to treat cancer with live viruses transformation and the occurrence of five decades ago, interest in naturally various morbid states. oncolytic viruses has lagged behind the
The school of professor Nicolau support for engineered adenoviruses and provided significant arguments for the herpesviruses as cancer therapeutics. involvement of viruses in the other fields Recently, however, there has been
renewed interest in the high potency and carcinoma); and animal T-cell Leukemia selectivity of these naturally occurring Viruses (bovine, murine T-cell
19, 20agents. The criteria most often leukemias).
used in determining causality were
Levaditi and Nicolau were the first consistency of the association, either to study the action of a neurotropic strain epidemiologic or on the molecular level, of vaccinia virus on tumours of mice and and oncogenicity of the agent in animal rats. They found epitheliomas of these 21, 22models or cell cultures. Whereas for
animals to provide an excellent culture most of the tumour viruses the viral medium for the virus in contrast to genome persists in an integrated or sarcoma. These findings were in accord episomal form with a subset of viral genes with their previous investigations where expressed in the tumour cells, some agents neurovaccinia was shown to have (Hepatitis B virus) are not inherently ectodermal rather than mesodermal oncogenic, but infection leads to tropism. transformation of cells by indirect
Studying tumours infected with 23, 24means. For some malignancies the neurovaccinia in immune animals Levaditi viral agent appears to serve as a cofactor and Nicolau showed that virus did not (Burkitt's lymphoma-EBV; mesothelioma survive in the immune host. If a portion of - SV(40)). For others the association is the tumour were transplanted into non-inconsistent (Hodgkin's Disease, breast immune animal, it would support growth cancer - EBV) and may either define of the infectious agent. The proliferative subsets of these malignancies, or the virus power of the transplantable tumour was may act to modify phenotype of an also interfered and is not always possible established tumour, contributing to tumour to make successful transplants from progression rather than causing the tumour. tumours carrying the vaccinia virus. In many other cases the association with
Nicolau and his co workers malignancy is less consistent or still developed investigations among many emerging. For example, despite the potent animal and human viruses that contribute oncogenic properties of some strains of 18to a variety of malignancies. Between human adenovirus in tissue culture and most studied viruses linked to cancers animals the virus has not been linked with were human papillomaviruses (cervical any human cancers. Finally it is likely that carcinoma); human polyomaviruses more agents, most likely viruses, both (mesotheliomas, brain tumours); Epstein-known and unidentified, have yet to be Barr virus (B-cell lymphoproliferative implicated in human cancer. In the diseases and nasopharyngeal carcinoma); meantime study of tumourigenic infectious hepatitis viruses (hepatocellular
agents will continue to elucidate molecular 5. Levaditi C., and Nicolau S., Vaccine et oncogenic processes. neoplasmes. Ann. Inst. Pasteur, 1923, 37,
6. Levaditi C., Nicolau S., Sur le culture du Viruses have been used for cancer
virus vaccinal dans les neoplasmes treatment for over a century. From the
epitheliaux. Compt. Rend. Soc. Biol. early clinical studies with various wild-(Paris), 1929, 101, 334. type viruses, to the modern trials with 7. Nicolau S. S. & Kopciowska L A new
stain method. Compt. Rend. Soc. Biol. engineered viruses, virotherapy has
(Paris) 1929, 101, 655-7 emerged as a promising therapeutic
8. Nicolau S.S. & Kopciowska L. 19strategy. In a recent review, which also Persistence of rabies virus in vaccinated mentions Levaditi and Nicolau priority, animals. Compt. Rend. Soc. Biol. (Paris),
1932, 110, 348-351. japanese authors discuss the progress and
9. Nicolau S.S., and Galloway I. Preliminary challenges associated with oncolytic
note on the experimental study of enzootic virotherapeutic agents, summarizing the encephalo-myelitis (Borna disease) Br. J. data from clinical reports, and the Exp. Pathol. 1927, 8, 336-341. implications of this data for future 10. Levaditi C. and, Nicolau S. S., Virus et
25tumeurs. Ann Inst Pasteur 1923, 37, 1-3. virotherapy development. Beyond
11. Nicolau S., Kopciowska L., Balmus G. historical perspective on the development Inclusions cytoplasmiques simulant les of oncolytic virus the reviewers present corps de Negri dans le cerveau de la the encouraging results of recent clinical souris normale. . Compt. Rend. Soc. Biol.
(Paris) 1933, 113, 851-855. trials (e.g., an modified herpesvirus has
12. Nicolau S.S., Galloway I.A., Dimancesco-been tested in clinical trial of nearly 250 Nicolau O. ? Étude sur les septinévrites à patients and approved for human use by ultravirus neurotropes ? Masson, Paris, the Chinese FDA). 1929.
13. Nicolau S.S., and Galloway I. Borna
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Nicolau, Ed. Academiei R.P.R., Bucharest, Books 1957. 1. Şt. S. Nicolau HEPATITE 8. Şt. S. Nicolau, Al. Rădulescu, N. M.
INFRAMICROBIENE (“Viral hepatitis”) Constantinescu, N. Cajal, G. Marinescu,
- Ed. Academiei R.P.R., Bucharest, 1954. POLIOMIELITA – („Poliomyelitis”), Ed.
2. V. BABEŞ (OPERE ALESE) („Selected Academiei R.P.R., Bucharest, 1961.
works of Victor Babeº”) Vol. I – (Şt. S. 9. Şt. S. Nicolau, N. M. Constantinescu, N.
Nicolau, M. Babeş, Fl. Horodniceanu, Cajal. TURBAREA („Rabies”) - Ed.
eds), Ed. Academiei R.P.R., Bucharest, Academiei R.P.R., Bucharest, 1962.
1954. 10. Şt. S. Nicolau (ed) ELEMENTE DE 3. V. BABEŞ (OPERE ALESE) (Selected INFRAMICROBIOLOGIE SPECIALĂ
works of Victor Babeº”) Vol. II - Şt. S. („Infections of inframicrobial etiology”) –
Nicolau, M. Babeş, Fl. Horodniceanu, Ed. Medicală, Bucharest, 1962.
eds), Ed. Academiei R.P.R., Bucharest, 11. Şt. S. Nicolau, N. Constantinescu
1959. RICKETTSII ŞI RICKETTSIOZE 4. Şt. S. Nicolau CANCER ŞI VIRUSURI. („Infections of rickttsial etiology”-, Ed.
CÎTEVA CONSIDERAŢII Academiei R.S.R., Bucharest, 1965.
PRIVITOARE LA IPOTEZA VIROTICĂ 12. Şt. S. Nicolau, Elisabeta Nastac,
A CANCERULUI („Cancer and Viruses – VIRUSURI ŞI TUMORI („Viruses and
remarks on the cancer viral etiology”), Ed. tumours”) - Ed. Academiei R.S.R.,
Academiei R.P.R., Bucharest, 1955. Bucharest, 1968. 5. Şt. S. Nicolau ELEMENTE DE 13. Şt. S. Nicolau, N. Drăgănescu
INFRAMICROBIOLOGIE GENERALĂ HERPESUL („Hepres viruses”) - Ed.
(„Basic inframicrobiology”), Ed. Academiei R.S.R., Bucharest, 1968.
Academiei R.P.R., Bucharest, 1956.
6. Şt. S. Nicolau (editor) PROBLEME DE
INFRAMICROBIOLOGIE („Progress in
inframicrobiology”)- coautori: Şt. S.
Nicolau, N. Cajal, A. Derevici, C. Iacob,
G. Marinescu, S. Mateescu, R. Portocală,
D. Sărăţeanu, J. Schwartz, Ed. Medicală,
7. Şt. S. Nicolau HEPATITELE