What is immunology?

The Science of Immunology

The science of Immunology encompasses the study of the development, anatomy functions and malfunctions of the immune system, all of which are of fundamental importance to the understanding of human disease. The immune system is made up of many types of molecules and cells that are distributed in every tissue of the body, as well as specialized lymphoid organs, which act in a coordinated manner to prevent or eliminate microbial infections, to suppress the growth of tumors, and to initiate repair of damaged tissues. The immune system normally recognizes and responds to foreign molecules or damaged self, but not healthy host cells and tissues. The innate immune system maintains barriers to microbial invasion and provides critical biochemical and cellular first responders to infections that are absolutely essential for survival in a world teeming with microbes. Innate immune recognition initiates stereotypical inflammatory or anti-viral responses to a limited number of molecular patterns that are shared by different pathogens or expressed by injured or infected host cells. The more highly evolved adaptive immune system relies on collections of millions of clones of B and T lymphocytes to provide protection for the host, each clone capable of recognizing a distinct molecule.  Furthermore, B and T lymphocytes are capable of differentiating into several different types of effector cells that perform distinct functions, and into long-lived memory cells that prevent or minimize repeat infections by a microbe. 

Immunology and Disease

Many diseases occur when there are fundamental defects in the immune system, or when the normal immune system is challenged in ways that evoke responses that damage rather than protect host cells and tissues. These diseases cause significant morbidity and mortality in every human population worldwide. Immunodeficiency diseases are manifest by increased risk of infections and tumors, and are caused by gene mutations, malnutrition, certain viruses such as HIV, or by treatments for cancer. Immune responses that are inappropriately targeted against self-molecules result in autoimmunity, which is manifest by diverse clinical problems related to the tissues or organs involved. Autoimmune diseases are caused by a combination of inherited genes and environmental factors that result in a failure of the mechanisms of self-tolerance and immune regulation. Excessive or chronic immune responses to infections are often the cause of disease related to certain microbes that are not cytopathic by themselves. Similarly, immune responses to otherwise nonpathogenic environmental antigens are the basis for allergic diseases. As the science of Immunology has progressed, it has become clear that immune responses are key to the development of many common disorders not traditionally viewed as immunologic in nature, including metabolic, cardiovascular, neurodegenerative, and neoplastic diseases.

Immunology Research at Harvard

Harvard investigators have historically made many major contributions to the field of Immunology (see History of Immunology at Harvard).  Current research activities at Harvard Medical School and affiliated institutions promise to bring more important discoveries and development of new therapies.  Some examples of these activities include:

  • Transcriptional profiling and proteomics of the many different subsets and functional states of the cells of the immune system,
  • In vivo confocal and multiphoton imaging of pathogen-host cell interactions;
  • Studies of the manipulations of the intestinal microbiome on immune responses and autoimmune disease,
  • Evaluation of blockade of T cell inhibitory molecules for the treatment of cancer; and
  • The use of inhibitory micro RNAs to modulate immune responses.

Browse People and Labs to find out more about the current scope of Harvard Immunology research.