Katerina Kavaldzhieva is an assistant professor in the Biology Department at the Medical University of Sofia. She holds a Master's degree in Zoology and Parasitology from Sofia University St. Kliment Ohridski. Her specialty is medical biology, and she is a PhD student in immunology. Her research interests include immunology; human fertility and sterility; sperm antigens and autoimmunity; autoimmune disorders; and heat shock proteins.

Nikola Mladenov has been head assistant professor in the Biology Department at the Medical University of Sofia since 2016. He holds a Master's degree in cell biology and pathology and a PhD in molecular biology. His specialty is medical biology, and his research interests include the immunology of human reproduction, fertility and sterility, biomembranes, and cell cultures.

Maya Markova is an associate professor in the Biology Department of the Medical University of Sofia. Her PhD is in morphology, and her specialty is medical biology. Her skills and expertise include reproductive biology, sperm morphology; sperm antigens and autoimmunity; the cell biology of gametes; human fertility and sterility; and autoimmune disorders.

Kalina Belemezova is an assistant professor in the Department of Biology at the Medical University of Sofia. She holds a PhD in immunology and a Master of Science in biochemistry. She is a scientist and clinical researcher with 15 years of experience in stem cell biology and 8 years of experience in genetics testing. Her research interests are in the fields of cell cultures, mesenchymal stem cells, reproductive genetics, human fertility and sterility, and immunology. She has experience working with multiple molecular biology techniques, such as ELISA, confocal microscopy, Western blot, SDS and agarose electrophoresis, MACS, RT-PCR, immunofluorescence, etc.