BIOL 202 Lecture 10: Chapter 20: Innate Immunity

7 Pages
Unlock Document

Biological Science
BIOL 202
Cathie Overstreet

Chapter 20: Resistance and the Immune System Innate Immunity • Innate immunity is obtained by birth. • Metchnikoff (1908) directly observed the activity of the immune system in a clear-colored starfish. o Doctrine of phagocytosis: a body responds to pathogens through the release of macrophages at site of pathogen to initiate phagocytosis. o Macrophages take the material that they engulf, chop it up, and display it on the surface. ▪ This material enters the lymph nodes and the lymph nodes search for a b-cell or t-cell that match against that material; that particular b/t cell is then activated. Host Immune Defenses • Immunology: study of how immune system functions to prevent infection. • Innate immunity: immediate response. o Effector molecules (molecules present at birth); present in skin, mucus, membranes, and secretions (tears, etc). o Innate immunity keeps infection in check while cytokines are sent in order to initiate adaptive immunity. • Adaptive immunity: slow response. o Takes about a week since it requires activation and antibody production. o Highly specific to a particular pathogen. o Antibodies are present for life. Host Immune Defenses • Blood consists of: o Fluid ▪ Serum: cell free part of blood. ▪ Water, minerals, salt, proteins, antibodies, hormones. o Plasma ▪ Serum that contains clotting agents. o Blood and immune cells ▪ Platelets ▪ RBC (erythrocytes) ▪ WBC (leukocytes) Leukocytes • Neutrophils (phagocytes): o Contain digestive enzymes and antimicrobial agents that can kill pathogens. • Eosinophils: contain toxic compounds to defend against parasites. • Basophils: act in allergic reactions. • Monocytes: o Last only a couple weeks but mature into macrophages. • Lymphocytes: o Natural killer cells; destroys virus infected and abnormal cells. ▪ Kills cancer cells. • Dendritic Cells o Present in every portal of entry. Lymphatic System • Cells and Tissues Essential to Immune Function • Thymus ensures that T/B-cell does not target the body (self-molecule). o After being ‘educated’ by the thymus, these cells enter the lymph nodes. • Lymph nodes: o This is where B/T -cells are located. o Dendritic cells and macrophages display what they have captured to the B/T-cells (recall—these are antigen presenting cells). 2 ▪ Cortex: B-cells. ▪ Medulla: T-cells. Invaders: Pathogen Identification • Recognition Phase o Body’s immune cells need to distinguish normal body cells from the invader. o Identify self-molecule from non self-molecule. ▪ Pathogens have flagella, peptidoglycan, lipopolysaccharides, etc… while the body’s cells do not. • Activation Phase o Neutrophils, macrophages, dendritic cells are put in action as the first responders. ▪ Neutrophils come first; monocytes turn to macrophages; dendritic cells come last. • Effector Phase o Notification: signaling molecules are sent by effector cells in order to alert more cells (phagocytic) to the site of pathogenic infection. ▪ Cytokine: a molecule secreted from cells (DC, macrophages, T-cells) that communicates to other phagocytic cells to the site. • Interleukin: cytokines that are involved in the communication between leukocytes; bind to cytokine receptors on target cells. • Chemokines: trigger attraction of leukocytes. o Create a chemical gradient to attract cells to that site. Adaptive Immunity • Has to acquire information from whatever has been infecting the body. o This requires the presence of antigen presenting cells. • We have billions of T-cells and millions of b-cells. 3 o However, it takes long to create antibodies since the T/B-cells need to be educated. Interleukins Between Leukocytes • A macrophage has to trigger a specific response to a pathogen it has found. Suppressor of Cytokine Signaling (SOCS) • At some point, a cytokine storm is possible in which there are too many white blood cells in an area; can be deadly. • There is a gene pro
More Less

Related notes for BIOL 202

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.