Kiril Bratanov

In early October 1986, Bratanov participated in an international symposium in New Delhi, India. A week after his return, while preparing his opening address to the forthcoming Bulgarian-Egyptian Symposium on Biotechnologies in Reproduction, to be held in Varna, he suffered a heart attack and passed away on 16 October at the age of 75. Bratanov was buried at the Central Sofia Cemetery.

At the 3rd symposium on Immunology and Reproduction in 1975, the International Society for Immunology of Reproduction (ISIR) was founded at the proposal of Kiril Bratanov who was elected as its first president and served until 1983. At the 3rd ISIR Congress in 1986 in Toronto, Professor Rupert Billingham, an immunologist and one of the pioneers in organ transplantation, said:

In 1969, ICCIR held a smaller meeting on "Immunology and Reproduction" at the WHO headquarters in Geneva and elected the ICCIR Steering Committee with Kiril Bratanov as president. The main aim of ICCIR has been to coordinate research in the area of reproductive immunobiology across the world and to periodically hold international symposia in Varna, Bulgaria, which have become a major forum in the area of experimental and clinical reproductive biology and immunology in humans and animals. In honor of its founder and past president, ICCIR awards the medal "Kiril Bratanov" (shown on the right) to researchers with outstanding contributions to reproductive immunobiology. The 15th International Symposium for Immunology of Reproduction was held in June 2018 in Varna, Bulgaria.

In 1967, he became a full member of the Bulgarian Academy of Sciences (Academician). He was also elected Honorary Member of the French Academy of Veterinary Sciences, the German Academy of Agricultural Sciences, the Belgian Royal Academy of Medicine, the Spanish Royal Academy of Veterinary Sciences, the Italian Society of Veterinary Science, and the Academy of Agricultural Sciences of the Soviet Union.

In September 1967, Kiril Bratanov and his closest collaborators, after intensive correspondence with other researchers in reproductive immunology, convened the First Symposium on Immunology of Spermatozoa and Fertilization in Varna, Bulgaria. Participants from Austria, Australia, Belgium, Bulgaria, Czech Republic, Denmark, Germany, France, UK, Hungary, Italy, Norway, Netherlands, Romania, Sweden, USA, USSR, and Yugoslavia attended the symposium. The World Health Organization (WHO) and the Food and Agricultural Organization (FAO) were also represented. During the symposium, the International Coordination Committee for Immunology of Reproduction (ICCIR) was founded.

Between 1943 and 1986, Kiril Bratanov was director of the Institute of Biology and Immunology of Reproduction and Development of Organisms at the Bulgarian Academy of Sciences. Today the Institute of Biology and Immunology of Reproduction "Acad. Kiril Bratanov" bears his name in honor of his contributions to science.

Bratanov's academic career began in 1940 when he became Assistant Professor at the Department of Physiology and Biochemistry at the School of Veterinary Medicine, University of Sofia. Between 1948 and 1976, he was Professor and Chair of the Department of Obstetrics and Artificial Insemination at the School of Zootechnology, University of Agricultural Sciences in Sofia. Kiril Bratanov also held positions as President of the University of Agricultural Sciences (1956-1962) and Vice-President of the Bulgarian Academy of Agricultural Sciences (1962-1972). From 1976 until his death in 1986, he was Director of the Department of Biological Sciences at the Bulgarian Academy of Sciences.

After completing 6th grade in his hometown in 1928, Kiril Bratanov moved to the capital, Sofia, where he continued his studies at the 2nd Secondary School for Men (Втора софийска мъжка гимназия), graduating in 1930. He studied veterinary medicine at the University of Sofia and after receiving his doctoral degree in 1935, he spent two years as a veterinarian in the village of Dermantsi.

Kiril Tsochev Bratanov (Bulgarian: Кирил Цочев Братанов; 5 March 1911 – 16 October 1986) was a prominent Bulgarian biologist and pioneer in the area of immunology of reproduction.

Kiril Bratanov was born on March 5, 1911, in the town of Lukovit, Bulgaria as the third son of Tsocho Bratanov Radkinski, a teacher from Yablanitsa. His oldest brother, Professor Bratan Bratanov, studied medicine and became one of the most prominent Bulgarian pediatricians of his time. His other brother, Dimitar Bratanov, studied law and served as diplomat, ambassador, and Member of the Bulgarian National Assembly. Due to his political convictions as a member of the Bulgarian Social Democratic Workers Party (Broad Socialists), the father, Tsocho Bratanov, had difficulties securing a teaching position. The family lived in poverty on a vineyard on the outskirts of Lukovit.