This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2017, Subject name: Pathology
[{'content': 'Rolling of leucocytes on endothelial cells is mediated by which of the following proteins? \nSelect and explain. \nA. Selectins, B. Integrins, C. Transferrin, D. PECAM-1', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Rolling interactions of leucocytes are mediated by a family of proteins called as selectins 3 types of selectins: L - selectins ( on leucocytes ) , E - selectin ( on endothelium ), P-selectin ( On platelets, endothelium ) Integrins: Firm adhesion of leucocyte to endothelial cell is mediated by family of leucocyte surface proteins called as integrins Transferrin: Iron transpoing protein PECAM-1: (platelet endothelium cell adhesion molecule): Present in the inter-cellular junction between endothelial cells Help in migration of leucocytes', 'role': 'assistant'}]