Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

By the end of this section, you will be able to do the following:

Explain adaptive immunity
Compare and contrast adaptive and innate immunity
Describe cell-mediated immune response and humoral immune response
Describe immune tolerance

By the end of this section, you will be able to do the following:

Explain cross-reactivity
Describe the structure and function of antibodies
Discuss antibody production

By the end of this section, you will be able to do the following:

Describe hypersensitivity
Define autoimmunity

By the end of this section, you will be able to do the following:

Describe physical and chemical immune barriers
Explain immediate and induced innate immune responses
Discuss natural killer cells
Describe major histocompatibility class I molecules
Summarize how the proteins in a complement system function to destroy extracellular pathogens

Covers cells and tissues of the immune system, lymphocyte development, the structure and function of antigen receptors, the cell biology of antigen processing and presentation including molecular structure and assembly of MHC molecules, lymphocyte activation, the biology of cytokines, leukocyte-endothelial interactions, and the pathogenesis of immunologically mediated diseases. Consists of lectures and tutorials in which clinical cases are discussed with faculty tutors. Details of the case covering a number of immunological issues in the context of disease are posted on a student Web site.

This course addresses the challenges of defining a relationship between exposure to environmental chemicals and human disease. Course topics include epidemiological approaches to understanding disease causation; biostatistical methods; evaluation of human exposure to chemicals, and their internal distribution, metabolism, reactions with cellular components, and biological effects; and qualitative and quantitative health risk assessment methods used in the U.S. as bases for regulatory decision-making. Throughout the term, students consider case studies of local and national interest.

Complement is so called because it complements the function of antibody. It is a triggered enzyme cascade and there are more than 20 different proteins in the complement cascades, with most being enzymes or pro-enzymes. It can be activated by both the innate and adaptive immune systems and is one of the main innate protective mechanisms of invertebrates. Due to its destructive potential the complement system is heavily regulated but when activated it works largely by forming pore complexes as well as triggering acute inflammation and by promoting phagocytosis by macrophages and neutrophils.

Immune cells protect our bodies from both self-derived threats and exogenous pathogens, while keeping peace with normal cells and non-harmful commensal microbiota. They have various mechanisms to perform these tasks, a capacity that is essential for maintaining homeostasis. However, these same mechanisms can backfire, resulting in severe disorders such as immunodeficiency, chronic inflammation, allergy, degenerative diseases, and cancer. This course discusses the connections between normal physiology and disease by examining the developmental relationship between innate and adaptive immune cells as well as the functions and malfunctions of immune cells. The course familiarizes students with both basic biological principles (such as cell death and immune cell signaling) and clinical applications (such as immune checkpoint blockade). More generally, students learn to identify relevant primary research literature, critically evaluate experimental data, and reach their own conclusions based on primary data.

Macrophages are large, round cells that contain a central round nucleus and have abundant clear, often vacuolated, cytoplasm. Macrophages acts as sentinel cells; they have a role in destroying bacteria, protozoa and tumour cells, and release substances that act upon other immune cells. They are also responsible for clearing dead and damaged cells and tissue through the process known as efferocytosis. Macrophages are phagocytic, long lived and are found throughout the body.

This courses focuses on the fundamentals of tissue and organ response to injury from a molecular and cellular perspective. There is a special emphasis on disease states that bridge infection, inflammation, immunity, and cancer. The systems approach to pathophysiology includes lectures, critical evaluation of recent scientific papers, and student projects and presentations. This term, we focus on hepatocellular carcinoma (HCC), chronic-active hepatitis, and hepatitis virus infections. In addition to lectures, students work in teams to critically evaluate and present primary scientific papers.

Neutrophils represent up to 70% of all leukocytes in the blood stream (in humans there are approximately 4.4 million neutrophils / millilitre of blood) and are distinguished by their irregular multi-lobed nucleus and indistinct granular appearance. They are 10-12ľm and circulate in the blood for minutes to hours (average 6-8 hours) and lasting for 1-2 days in tissue. Although the most abundant leukocyte in the blood, the vast majority of neutrophils are found in the bone marrow (5x more) mostly as functionally immature precursor cells, although this varies between species with mice having a large pool of functional neutrophils in their bone marrow.

Phagocytosis is a very primitive system of defence against infection, having even been shown to exist in invertebrates and single cell organisms. The discovery was made in starfish larvae by Elle Metchnikoff who subsequently won the Nobel Prize for Medicine or Physiology in 1908. The process of phagocytosis itself is a form of endocytosis (cell eating), with vesicular internalisation being the method of removal of pathogens and dead cells (those that have undergone apoptosis, or Programmed Cell Death). This internalised vesicle is referred to as the "phagosome".

T cells are long lived and are involved in cell mediated immunity. Functionally they are divided by the expression of CD4+ or CD8+ markers. CD4+ T helper cells recognise antigens bound to MHC II complexes and are involved with the control of intracellular and extracellular pathogens; they can interact with CD8+, NK and dendritic cells or with B cells. Cytotoxic CD8+ T cells recognise the MHC I complex and destroy infected or neoplastic cells.