In Memoriam

Prof. Michael Sela (1924-2022)

Born in Poland in 1924, Prof. Michael Sela immigrated to British Mandate controlled Palestine in 1941. He studied chemistry at the Hebrew University of Jerusalem and received his PhD in protein chemistry, for research done at the Weizmann Institute, also from the Hebrew University (1954). A member of the Weizmann Institute faculty since 1950, he served as the founder and first Head of the Department of Chemical Immunology (1963-75), as Dean of the Faculty of Biology (1970-73), as the Institute Vice President (1970-71), as its 6th President (1975-85), and as Deputy Chairman of the Institute's International Board of Governors (1985-2004), and as a Life Member of the Board. He continued to be actively engaged in the Institute’s leadership after his term as President, serving on the Executive Council (which became the Executive Board), until his passing. In the last month of his life, he became a member of the newly established Department of Immunology and Regenerative Biology.

Prof. Sela is widely known in the scientific world for his seminal research in immunology, specifically for his development and use of synthetic antigens, molecules that trigger the immune system response. These studies have led to a deeper understanding of the genetic control of the immune response, as well as to the design of vaccines based on synthetic molecules. One of Prof. Sela’s major research efforts culminated in the approval by the U.S Food and Drug Administration of copolymer-1 (Copaxone®), a drug for multiple sclerosis. Copolymer-1 was originally synthesized and developed by Prof. Sela jointly with the Institute’s Prof. Ruth Arnon and Dr. Dvora Teitelbaum. Another practical medical success of his research was the discovery of synergistic effect of an antibody conjugated and a small chemotherapeutic drug in the treatment cancer, and later on a similar synergistic effect due to two distinct antibodies against the same receptor.

Prof. Sela held a number of visiting professorships and membership of several prestigious academies. His numerous prizes and honors include the Israel Prize in the Natural Sciences (1959); the Rothschild Prize in Chemistry (1968); together with his colleague Prof. Ruth Arnon the Wolf Prize in Medicine (1998). the Albert Einstein Golden Medal, UNESCO (1995); the Harnack Medal of the Max Planck Society (1996); the Interbrew-Baillet Latour Health Prize of Belgium (1997); the Commander's Cross of the Order of Merit Award of Germany (1986); Officier (1987) and Commander (2011) of the Order of Legion of Honor, France (1987); and Grand Officier of the Italian Solidarity Star (2007). Sela and colleague Prof. Ruth Arnon were also named the 1998 Wolf Prize Laureates in Medicine. Sela was awarded honorary doctorates from the Universities many universities and was made an honorary fellow of the Open University of Israel.

Michael and his wife Sara were pillars of the Weizmann community, and, as ardent and generous supporters of music and the arts, their home on campus became an epicenter of the Israeli social and cultural scene, and Institute events. They generously supported the Weizmann Institute, funding both science and cultural activities, including the renovation of the Michael Sela Auditorium.

Michael’s legacy will live on and his passion, sharp intellect, and vision will remain as an example and inspiration to all who were fortunate to know him.

He is survived by his wife Sara and their three daughters, Irit, Orlee and Tamar.
Prof. Nir Friedman (1968-2021)

Our friend and colleague Prof. Nir Friedman untimely passed away, after a two-decade long battle with cancer. A physicist and systems immunologist, he studied cell-cell communication networks, immune disorders and cancer. Husband to Ofra and father of three children, Nir was born in Tel Aviv, and completed a BSc in physics and mathematics (1989) in the prestigious Talpiot program at the Hebrew University of Jerusalem. He received his MSc in physics from Tel Aviv University, and then went on to earn his PhD in experimental physics with Prof. Nir Davidson at the Weizmann Institute in 2001. After a highly productive four-year postdoctoral fellowship at Harvard University with Xiaoliang (Sunney) Xie, he returned to Weizmann’s Department of Immunology in 2007

Nir combined novel experimental tools with powerful computational approaches. From the development of the immune system during the preterm (pregnancy), to the role of T cells in type 1 diabetes, autoimmune diseases, and other diseases including cancer, to the changing immune cell landscape during the aging process, he studied the immune system in depth. He also developed new microfluidic devices including a fluorescent microscopy method that makes it possible to track the behavior of individual immune cells in real time, as well as methods to analyze properties of T cells and their receptors.

Nir worked with clinicians to understand how T cells participate in the body’s response to pathogens, such as viruses, bacteria, and other microorganisms, as well as to malfunctioning cells of the body, such as cancerous cells.
“Nir cherished the interdisciplinary, collaborative atmosphere at Weizmann, and the incredibly warm friendship and support of the campus community, which was significant for both of us.” says Ofra, herself a bioimaging analyst in the Weizmann Life Sciences Core Facilities.

“Nir had the courage to follow his heart and study the most chaotic and complex systems, namely the human immune system,” said Prof. Uri Alon, a good friend and long-time colleague, from the Department of Molecular Cell Biology.

A close collaborator of Prof. Friedman, Prof. Benny Chain, Professor of Immunology at the University College London and Trustee of Weizmann UK, said, “Nir combined an extraordinary clarity and originality of thought, with an honesty, integrity and generosity. His bravery in the face of adversity, and his unfailing energy, enthusiasm and positive attitude were a true inspiration to all who knew him.”

“Throughout over a decade of collaboration,” said Prof. Benny Geiger, Head of the Department of Immunology, “we were all fascinated by his unique personality, which combined a huge heart, brilliant intellect, and deep cross-disciplinary vision, with gentle and genuine modesty that touched everyone who interacted with him.”
Prof. Avi Ben-Nun (1947-2019)

“What furthered me most in life was that I dared to set high goals”, is what Prof. Ben-Nun used to say. He passed away on January 18, 2019, at the age of 72. He earned his master's degree in microbiology, cum laude, from Tel Aviv University in 1974 and his doctorate in immunology under the advice of Prof. Irun Cohen at the Weizmann Institute in 1981. A year later Avi moved to Boston for his postdoctoral studies at the Department of Genetics at Harvard Medical School. In 1984 he returned as a young scientist to the Department of Immunology at the Weizmann Institute. He was appointed Associate Professor in 1993 and received full professorship in 2007.

The science is still alive: papers dedicated to his memory

1. Kaushansky N.,* A. Kaminitz, H. Allouche-Arnon and A. Ben-Nun. 2019. Modulation of MS-like disease by a multi epitope protein is mediated by induction of CD11c+CD11b+Gr1+ myeloid-derived dendritic cells. J Neuroimmunology.333:476953. *corresponding author

https://doi.org/10.1016/j.jneuroim.2019.04.013

2. Kaushansky N., E. Bakos, S. Becker-Herman, I. Shachar*, and A. Ben-Nun* . 2019. Circulating

picomolar levels of CCL2 downregulate ongoing chronic EAE by induction of regulatory

mechanisms. J Immunol. 203(7):1857-1866 *Co- last author.

https://doi.org/10.4049/jimmunol.1900424

3. Zilkha-Falb, R., Kaushansky N., and A. Ben-Nun"The Median Eminence, a new oligodendrogenic niche

in the adult mouse brain”, Stem Cells report, under minor revision.

Prof. Ben Nun’s research focused on autoimmune diseases, in particular on Multiple Sclerosis (MS). Multiple sclerosis (MS) is a disease of the human central nervous system (CNS), characterized by perivascular inflammation accompanied by primary demyelination and axonal damage. Although the etiology of the disease is unknown, it is believed that MS results from autoimmune mechanisms, leading to the destruction of myelin, presumably initiated by abnormally activated, potentially pathogenic, autoimmune T cells that recognize components of the myelin sheath in the CNS of MS patients. One of Avi’s major contributions, which was considered a breakthrough in the field of immunology, was the in vitro production of T cells against myelin epitopes. Following injection of these cells, mice develop MS-like disease (experimental autoimmune encephalomyelitis, EAE). This find was published in the top-tier journal Nature and paved the way for the development of therapies for MS and several other diseases. Prof. Ben Nun’s research contributed to the identification of potential target antigens in MS, e.g. myelin oligodendrocyte glycoprotein (MOG), myelin-oligodendrocytic basic protein (MOBP), and oligodendrocye specific protein (OSP). Injection of these antigens to laboratory animals resulted in EAE and T-cell reactivity against these antigens in MS patients were detected. MS is a complex and dynamic anti-myelin autoimmune disease. Prof. Ben Nun therefore believed that the ultimate goal of immune therapy for MS is a multi-target approach to immune-specific modulation that targets only the deleterious autoimmune T cells without compromising the immune competence of normal physiological functions. He also examined the use of stem cells for the regeneration and repair of damaged myelin in MS. Prof. Ben-Nun's scientific contribution constitutes a milestone in the world of immunology and in the study of autoimmune diseases in particular
Prof. Yoram Salomon (1941-2017)

Prof. Yoram Salomon of the Department of Biological Regulation was a leading cancer researcher whose insights are being used to save and extend lives. He passed away in 2017 at age 76 leaving behind his wife, Daniela, their three children, and six grandchildren.

Born in Tiberias, Israel, Yoram Salomon earned his Ph.D. in Biochemistry from the Hebrew University of Jerusalem in 1972. After three years of postdoctoral research at the National Institutes of Health in Bethesda, Maryland, he joined the Department of Hormone Research at the Weizmann Institute of Science in 1975, was promoted to Associate Professor in 1980 and Full Professor in 1990. As a Visiting Professor at Rockefeller University in New York in 1981, he spent a sabbatical at the Population Council before returning to the Weizmann Institute, where he was appointed Head of its Biological Services (1982-1986). Other appointments at the Institute include Chairman of the Department of Hormone Research (1986-1992), where he was the incumbent of the Charles W. and Tillie K. Lubin Professorial Chair, Chairman of the Scientific Council (1995-1996), and Chairman of the Professorial Promotions Committee of the Life Sciences Faculty (1999-2002).

In his early years at the Weizmann Institute of Science, Prof. Yoram Salomon explored the mechanisms of signal transduction of hormonal regulation.

Later he focused on the development of new therapeutic approaches to cancer, age-related macular degeneration and, more recently, ectopic pregnancy, in collaboration with Institute colleague Prof. Avigdor Scherz, of the Department of Plant Sciences.

His main research focus in the last 20 years of his life was the collaborative project with Avigdor Scherz in which the two scientists developed a therapy to eradicate tumors by destroying blood vessels surrounding the growths, using light and chlorophyll derivatives.

Shortly after his death the therapy called Tookad-Soluble Vascular Targeted Therapy (TS-VTP®) was approved. In the link below, see a short video (in Hebrew) in which his colleague Avigdor Scherz, and his wife Daniela are interviewed about the research and approval of the treatment.

Avigdor Scherz is quoted referring to Yoram as reliable, knowledgeable and a mensch and Daniela mentions how happy he was when a month before his death he heard that the treatment was about to be approved.

Yoram also developed a novel approach to functional magnetic resonance imaging that enables online monitoring of the photodynamic process, with Prof. Michal Neeman of the Institute’s Department of Immunology and Regenerative Biology.

One of his passions and talents was photography, particularly of nature.
Prof. Israel Schechter (1935-2012)

Israel Schechter first studied the active site of enzymes (proteases) discovering that their size is larger that expected, with important interactions in regions remote from the catalytic site allowing high binding energy of enzyme-inhibitor complexes. This led to rational design of inhibitors developed at 1990th into drugs against HIV (inhibitors of virus proteases) and revolutionized AIDs disease turning a lethal into a chronic disease. Other drugs were against hypertension, congestive heart failure, diabetes, cancer (methotrexate), bacteria (antibiotics), anti-viral (relenza) but also Viagra.

The Schechter-Berger model of the active site of enzymes divided into subsites (1967) became a milestone in enzymology and a template for drug design. His studies on the antibody combining site (1967) revealed a region of four subsites of independent Interactions being just additive, i.e., ligand’s binding energy was the sum of binding energy attained in each subsite. Israel also studied the biological aspects of the immune response focusing on cellular localization of antigen in relation to antibody producing cells. Other studies focused on immunological tolerance, antigenic competition, the role of antigen conformation on immunogenicity as well as the development of skin grafts with decreased immunogenicity and increased resistance to infection for the treatment of burnt patients. He also studied the molecular biology of schistosome, the cause of bilharzia., in collaboration with Egyptian scientists. Back in 1973 a major attention was devoted to the evolution of antibody diversity with the primary goal of isolating an immunoglobulin (Ig) gene. He was the first one to isolate pure mRNA encoding for a single protein (which could be translated to the first gene). He developed a general procedure based on the specific immune precipitation of polysomes engaged in the synthesis of a given molecule – here the Ig. The mRNA which was translated into the Ig precursor containing a signal peptide of marked hydrophobicity while intracellular but cleaved upon secretion, later identified as a property of other proteins as well
Prof. Mordechai Liscovitch (1951-2008)

Born in Tel Aviv, Israel, in 1951, Moti Liscovitch received a B.Sc. degree in the Life Sciences in 1976 from Tel Aviv University. He earned his M.Sc. in 1979 and a Ph.D. in 1984, both from the Weizmann Institute of Science. After spending two years as a postdoctoral fellow at the Massachusetts Institute of Technology (MIT), he joined the Weizmann Institute faculty in 1986 and was promoted to Associate Professor in 1994 and to Full Professor in 2001. He was a Visiting Professor at Harvard Medical School and MIT. Moti received numerous honors, including the H.R. Lindner Memorial Prize in Biochemical Endocrinology awarded by the Israel Endocrine Society, and the Jeanette and Samuel Lubell Prize of the Weizmann Institute’s Scientific Council. He was the incumbent of the Harold L. Korda Professorial Chair in Biology.

Prof. Mordechai (Moti) Liscovitch’s research interests concerned the molecular signals and mechanisms involved in the proliferation, survival and dispersal of cancer cells. One of the main avenues of research in his laboratory focused on a protein called caveolin-1, originally believed to act as a tumor suppressor. However, Liscovitch found that this protein is present in large amounts in multidrug-resistant cancer cells, and his team explored the hypothesis that in advanced, multidrug-resistant and metastatic cancer, caveolin-1 might promote the survival and dispersal of malignant cells. In another avenue of research, Liscovitch focused on phospholipase D, an enzyme that plays an important role in signal transduction and intracellular membrane traffic. His aim was to elucidate the enzyme’s regulation and mechanism of action. Liscovitch also developed an innovative approach for generating various protein forms designed to be susceptible to drugs. The approach, as well as other findings in the lab, may in the future help design innovative cancer therapies, particularly for the treatment of multidrug-resistant and metastatic cancer.

Moti passed away in 2008 leaving his wife, Bilha and two children, Noa and Dror. He was interested in nature conservation and enjoyed gardening.
Prof. Michael Feldman (1926-2005)

Professor Feldman graduated from the Hebrew University in Zoology and trained with noted embryologist and philosopher of science Conrad Hal Waddington at the Institute of Animal Genetics in Edinburgh. Michael joined the Weizmann Institute in 1955, was promoted to full professor in 1961, and at the same year founded the Department of Cell Biology, which he headed until his official retirement in 1990.

As a professor Emeritus he joined the department of immunology when departments were rearranged. In the intervening years he also served for varying periods of time as Dean of the Faculty of Biology and of the Feinberg Graduate School, Chairman of the Weizmann Institute Scientific Council, visiting professor at Stanford University and at the Memorial Sloan Kettering cancer Institute, New York, and also served as Fogarty Scholar in Residence at the NIH. In 1977 he was elected Member of the Israel Academy, and in the following years received a number of national and international awards, including the Rothschild Prize, Honorary Doctorate of Ben Gurion University of the Negev, Honorary Fellowship of the Open University of Israel, Membership of the World Academy of Arts and Sciences and the San Marino Prize for Medicine. His activities in scientific and other areas in Israel and worldwide are too many to mention.
Professor Feldman’s research interests were primarily immunology and cancer research with special focus on metastasis. He also contributed seminaly to other fields like macrophage biology and transplantation. He published over 350 papers and book chapters. Michael was one of the rare scientists who could traverse comfortably the fields of both science and art. His many friends and admirers included not only with scientists in Israel and elsewhere, but also writers, painters and politicians.
Prof. Ofer Lider (1955-2004)

Ofer Lider began his PhD in 1983 in the Department of Immunology at the Weizmann Institute of Science, despite having recently been diagnosed with leukemia (CML). He completed his degree in the laboratory of Irun Cohen in 1987 and went on to a post-doctoral fellowship with Howard Weiner at the Harvard Medical School (1987-9). He returned to establish his own laboratory in the Department of Immunology, where he studied the regulation of the immune system and its interactions with the extra-cellular matrix (ECM). His unique research achievements earned him international acclaim and a professorship with tenure at the Weizmann Institute in 2001. Various treatments including two bone marrow transplantations failed to cure his leukemia, and Ofer Lider died in 2004 at the age of 49.

Despite his illness, Ofer went on to form a perfect union with Osnat, raise three daughters, create a family and build a home. He was a leader who never commanded, never asserted his will, never imposed. His influence rested on his quiet nobility and his care for the feelings of others. Ofer always made time to listen, to comfort, to advise, to identify with the fear and the pain of others. For himself, he always knew what was truly important, and he used his time well. Towards the end of his life, he wrote and published poetry, including the highly regarded book Beynotayim (In the Meantime). Despite his short years, Ofer lived many times over the measure of life lived by others. His life was his poetry.
In the spirit of his memory, Ofer’s family, friends and colleagues established a non-profit association dedicated to fostering the literary expressions of scientists in poetry and short stories – Life’s Verse (Shirat Hayav). This enterprise is now sponsored by the Weizmann Institute of Science as The Poetry of Science (Shirat HaMada). For more than a decade, over a thousand literary works have been submitted to the annual competition. In this enterprise, Ofer’s courageous life of creative science and literary creativity continue to enrich science and art.
Dr. Shmuel Shaltiel (1935-2002)

Shmuel Shaltiel was born in Greece and immigrated to Israel as a child. He was awarded his M.Sc. in Organic Chemistry and Biochemistry at the Hebrew University in 1960, and his Ph.D. in Biochemistry at the Weizmann Institute of Science in 1964. He joined the staff of the Weizmann Institute in 1967 and served the Institute as Deputy President, Acting President, as Dean of the Feinberg Graduate School, as Chairman of the Scientific Council, as the Head of the Department of Chemical Immunology, and as Head of the Department of Biological Regulation until 2000, where he was the incumbent of the Hella and Derrick Kleeman Chair of Biochemistry. He was a member of the National Planning and Budgeting Committee for Higher Education. Abroad, he was Scholar in Residence at the US National Institutes of Health, and a Visiting Professor at the University of California Berkeley, Lund University and ETH Zurich. He was also elected an Honorary Member of the American Society of Biochemistry and Molecular Biology.

Prof. Shaltiel’s major research interests involved the biochemistry of proteins and enzymes, and the relationship between their structure, function and regulation. He pioneered a conceptual new approach to the characterization and separation of proteins and cells (known as hydrophilic chromatography) which is now widely used in biotechnology, and for which he was awarded the Analytical Biochemistry Prize, awarded bi-annually by the European Societies of Analytical Biochemistry. In Israel, Prof. Shaltiel won the Hestrin, Laundau and Weizmann Prizes, and in 1994 was awarded the prestigious Rothschild Prize for highly-regarded research on cardiovascular disorders and the control of blood clot dissolution (fibrinolysis). His findings shed light on the regulation of fibrinolysis and thus had an impact on the design of new drugs for the diagnosis and treatment of a wide array of diseases associated with deregulation, such as thrombosis, stroke, and myocardial infarction.

He died at the age of 67 continuing his creative and original research right up until his death.

He was married to Sarah (Mass) and had two daughters, Orna (Cadmon) and Ruth (Waksman).
Prof. Nathan Trainin (1922-1999)

Born in Argentina Nathan graduated Medical school of the University of Cordoba and made Aliya to Israel in 1949 with his wife Zila. They settled in Kibuz Maabarot where he served as a rural physician, riding on horse, visiting settlements of new immigrants. He then served in the IDF as a physician. After release from service in 1956, he joined the Department of Experimental Biology of the Weizmann Institute, headed by Prof. Isaac Berenblum.

He focused on cancer research, studying a possible two stage mechanism in experimental leukomogenesis, using radiation and chemicals such as Urethan. He then moved to study the function of thymic tissue in diffusion chambers implanted in neonatally thymectomized mice. This led him to discover a thymic humoral factor shown to prevent wasting and influencing lymphopoiesis in such mice. He then proceeded to characterize this factor focusing on its role in the development of cell-mediated immune competence. In collaboration with Prof. Yigal Burstein from the Department of Organic Chemistry, the Thymic Humoral Factor (THF) has been purified from calf thymus and sequenced as an octapeptide. Together with Prof. Rina Zaizov from the Dept. of Pediatric Oncology at the Beilinson hospital a beneficial effect of THF in immunosuppressed children with lymphoproliferative neoplasia and generalized varicella was observed. Furthermore, in collaboration with Prof. Shlomo Ben-Efraim from the Tel Aviv University medical school, it was discovered that THF repairs immunodeficiency of mice cured from plasmacytoma. With Dr. Marit Pecht it was found that THF potentiates myeloid colony formation in bone marrow of intact and neonatally thymectomized mice. He published more than 200 papers and reviews. This research has been interrupted by the untimely death of Nathan.
Besides his research conducted almost till his last days, Nathan contributed to the society, heading the Israel CancerAssociation and helping cancer patients with advice and empath
Dr. Yoav Citri (1953-1995)

Yoav was born in Jerusalem on July 25, 1953. He performed his Ph.D. studies under the supervision of Prof. Michael Schramm at the Department of Biological Chemistry of the Hebrew University of Jerusalem. His research on analysis of the β3-adrenergic receptor led to the first functional reconstitution of a hormone receptor from its solubilized components. He received his Ph.D. degree in 1983 summa cum laude and was awarded the prestigious Kennedy Leigh Prize for the outstanding science graduate at the Hebrew University. Yoav's postdoctoral career was spent in two outstanding laboratories, that of Prof. David Baltimore at M.I.T. and of Prof. Michael Rosbash at Brandeis University. During this period, Yoav began to develop a deep interest in molecular neurobiology. His research focused on regulation of gene expression, in particular on characterizing expression of per, the Drosophila circadian rhythm gene.

He returned to Israel in 1987 as a Senior Scientist in the Department of Hormone Research at the Weizmann Institute, where he remained until his death in 1995. Yoav's major scientific focus was the brain; his dream was to exploit the power of molecular biology as a window into brain function. Armed with his exceptional graduate and postdoctoral training, and his formidable intellect and energy, he established a dynamic research group of talented students, postdocs, and technicians whom he directed in two major focus areas: What are the molecular mechanisms involved in the mammalian biological clock, and what mechanisms underlie brain plasticity? Yoav realized that in order to fully characterize the changes in gene expression pattern that presumably control these phenomena, it was essential to establish experimental paradigms that would provide improved sensitivity over conventional differential hybridization screening procedures. He concluded that it was essential to screen on a "clone by clone" basis, involving painstaking amplification of DNA from each clone, and had the courage to follow through on this idea, despite the enormous practical difficulties.

In retrospect, Yoav was clearly correct. The widely popular "gene hunts" now being performed extensively in academia and industry are based on the same principle, although the procedure has been greatly simplified by DNA chip technology, at that time not available to Yoav. After a prodigious team effort, Yoav and his colleagues were able to identify and characterize a large collection of genes, the candidate plasticity genes (CPGs), whose expression is modulated by treatment with the potent glutamate analog kainite. This collection includes genes with broadly diverse functions, consistent with the view that multiple molecular mechanisms underlie neuronal plasticity. Many of the genes identified are novel – their precise function and involvement in plasticity remain to be evaluated.

Yoav was an intensely passionate scientist. His attitude to research was uncompromising and his standards exacting. His recipe was simple yet profound: choose an issue to which you are deeply committed, no matter how difficult, and pursue it relentlessly, with all one's physical and intellectual resources. Yoav was a natural leader. He died in a car accident in 1995.

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In Memoriam

Prof. Michael Sela (1924-2022)

Prof. Nir Friedman (1968-2021)

Prof. Avi Ben-Nun (1947-2019)

Prof. Yoram Salomon (1941-2017)

Prof. Israel Schechter (1935-2012)

Prof. Mordechai Liscovitch (1951-2008)

Prof. Michael Feldman (1926-2005)

Prof. Ofer Lider (1955-2004)

Dr. Shmuel Shaltiel (1935-2002)

Prof. Nathan Trainin (1922-1999)

Dr. Yoav Citri (1953-1995)