Part IB Biology of Disease

The lectures of the Michaelmas term start with an Introductory lecture that provides an overview of the subject. It is followed by a set of lectures concerned with cell injury, inflammation, and healing. Cell injury is the starting point for most disease processes, and the basic initial response of the body to all types of cell injury is acute inflammation. The changes that occur during this process are dynamic and follow a predictable course in which changes in the micro-circulation play a crucial role in focusing the basic defences at the site of injury. The whole process of acute inflammation is orchestrated by elaborate molecular and cellular mechanisms.

Immunology

The immune response is the body's major defence against infectious agents. This section of the course, will present some of the fundamental characteristics of vertebrate immunology. The topics covered will include the ability of vertebrates to mount an adaptive immune response, the role of B and T lymphocytes, antibody structure, autoimmunity, and hypersensitivity.

An adaptive immune response has two phases: first the recognition phase in which an antigen is recognized as being foreign, and secondly, an effector phase in which antibodies and effector T lymphocytes eliminate the antigen, often by recruiting non-specific mechanisms such as complement and macrophage activation. The whole process requires considerable co-operation between cells of the immune system, and ingenious and intricate signalling mechanisms are involved.

Virology

Viruses are submicroscopic obligate intracellular parasites. At their simplest, they consist of a nucleic acid genome, which may be DNA or RNA, surrounded by a protective shell of repeating protein subunits. Viruses are however a diverse group, as there is considerable variation both in the coding potential of the genome, and in the different proteins, and their symmetrical arrangement, within the outer protein shell. In addition, some viruses acquire an outer membrane as they leave the host cell, and these viruses are therefore chemically more complex.

The virology component of the course will start by considering the diversity of viruses, and also their common features. Viruses are dependent upon host cell machinery for their replication, and the course goes on to cover virus replication, their ability to modify the host cell, and the responses of multicellular hosts to viral infection. The epidemiology of virus infection, and current and future strategies for combating viral diseases will also be addressed.

Bacteria are ubiquitous, and inhabit virtually every ecological niche capable of supporting life. Hundreds of bacterial species, both commensal and pathogenic, are found in association with the bodies of humans and other animals. Most bacterial species found in nature are harmless. Understanding how some bacteria cause disease requires a knowledge of those factors that render the bacteria virulent, or pathogenic, and also a knowledge of how the host responds to bacterial infection.

Bacterial pathogenicity may depend upon many factors and may involve many bacterial genes. The lectures in bacteriology will start by introducing bacteria as prokaryotic organisms, and then go on to address the basic principles of bacterial pathogenicity. These will include bacterial colonization, the production and actions of bacterial toxins, the entry of bacteria into epithelial cells and their passage through them, and the principles of epidemiology and control of bacterial disease.

The impact of parasitic diseases on man and his domestic animals can be devastating. The lectures on parasitology will provide a selected overview of the biology, immunology and epidemiology of parasites that cause diseases of major public health and veterinary concern. The parasites responsible for diseases in humans and domestic animals are an extraordinarily diverse group and include single celled protozoa and large multicellular nematodes. The manner by which these organisms gain access to their hosts and their interaction with the host are crucial components of the host-parasite interaction. In order to illustrate why many parasitic infections are serious and continuing public health problems, more detailed accounts of two major parasitic diseases, malaria and schistosomiasis, will be given.

Vascular disorders are major health problems in developed countries, and cardiovascular disorders are the leading cause of death in most Western societies. Vascular disorders are those resulting from abnormal blood flow to, from, or within an organ. The efficient circulation of blood containing all of the essential constituents is a vital necessity for the health of the whole organism. Any reduction in the blood flow through a vessel may lead to an inadequate blood supply, or ischaemia, of the tissues it supplies. If the ischaemia is sustained, then death of the tissue, or infarction, results.

This series of lectures will begin by providing an overview of mechanisms of haemostasis and thrombosis, and then go on to discuss atherosclerosis, heart failure and hypertension, and the causes and effects of ischaemia.

The word 'neoplasia' literally means 'new growth', and the lesion so produced is called a neoplasm or tumour. A tumour arises when there is growth dysregulation and an abnormal tissue mass is produced by cells that grow excessively and in a manner that is uncoordinated with normal tissues. Numerous factors have been implicated in the development of tumours. The lectures in this section of the course will look at the origins of tumours, the manner in which they cause illness and death, their epidemiology, the genetic basis of neoplasia, and the molecular basis of tumour therapy.

Easter Term (NST): The Future of Disease: New Threats, New Insights

This series of lectures are intended to illustrate some of the characteristics of the host and infectious agents that may determine whether an infection is established. The lectures will cover host resistance factors, immune evasion, HIV, opportunistic pathogens, and vaccination.