The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates the interior of all cells from the outside environment (the extracellular space) and protects the cell from its environment. The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of cells and organelles, being selectively permeable to ions and organic molecules. In addition, cell membranes are involved in a variety of cellular processes such as cell adhesion, ion conductivity and cell signalling and serve as the attachment surface for several extracellular structures, including the cell wall and the carbohydrate layer called the glycocalyx, as well as the intracellular network of protein fibers called the cytoskeleton. In the field of synthetic biology, cell membranes can be artificially reassembled.



Lloyd John Old (September 23, 1933 – November 28, 2011) was one of the founders and standard-bearers of the field of cancer immunology. When Old began his career in 1958, tumor immunology was in its infancy. Today, cancer immunotherapies are emerging as a significant advance in cancer therapy.Old's contributions to research established many of the principles and priorities of modern tumor immunology. In earlier work, he and his colleagues introduced Bacillus Calmette-Guérin (BCG) to tumor immunotherapy; discovered the first link between the major histocompatibility complex (MHC) and disease (leukemia); found the unexpected association between Epstein-Barr virus (EBV) and nasopharyngeal carcinoma; discovered Tumor necrosis factors (TNF); defined the concept of cell-surface differentiation antigens with the discovery of TL, Lyt (CD8), and a range of other mouse antigenic systems; discovered p53, independently with two other groups; and identified the tumor immunogenicity of heat shock proteins. Old is the author or co-author of more than 800 research publications. He was also a teacher helping young scientist as they began their career.

He held the William E. Snee Chair of Cancer Immunology at Memorial Sloan-Kettering Cancer Center (MSKCC), where he was director of the Ludwig Cancer Research New York Branch (then known as Ludwig Institute for Cancer Research, or LICR). He was also a trustee of the LICR Charitable Trust, and a trustee of the Virginia & D.K. Ludwig Fund for Cancer Research.6. From 1971 to 2011, he served as the founding scientific and medical director of the Cancer Research Institute (CRI), where from 2001 to 2011 he also served as director of the CRI/LICR Cancer Vaccine Collaborative (CVC), an international network dedicated to testing and optimizing therapeutic cancer vaccines. Old's previous appointments included chairman of the LICR board of directors (2006–2009), LICR scientific director (1988 to 2005), member of the Emeritus LICR Scientific Committee (1971–86), LICR chief executive officer (1995–2004), and associate director of research at MSKCC (1973–83).

Old served as a member of scientific advisory boards and committees including the Public Health Research Institute of the City of New York, the National Cancer Institute, and the American Association for Cancer Research. Old was also a member of the American Association for Cancer Research, New York Academy of Sciences, Reticuloendothelial Society, Society of Experimental Biology and Medicine, American Association for the Advancement of Science, American Association of Immunologists, National Academy of Sciences, the Academy of Cancer Immunology, and the American Academy of Arts and Sciences. He had also received honorary doctor of medicine degrees from Karolinska Institute, the University of Lausanne, and the University College London. He graduated from the University of California, Berkeley with a B.A. in biology and earned a medical degree from the University of California, San Francisco.

Old died November 28, 2011, in his New York City home, after several years battling advanced prostate cancer.