BY: MILANA BERNASEK RN

Know at least three components of the immune system

Describe at least two cells in the immune system and how they respond to infectious agents

Identify factors that influence the immune response to infectious agents

The spleen-A staging ground and place where immune system cells confront foreign microbes.

The Lymphatic System-(1)Lymphatic vessels form a circulatory system that operated in close partnership with blood circulation. (2) carries lymph, a fluid that contains WBC’s (chiefly lymphocytes). And (3) lymph nodes provide “meeting grounds”.

Arise in bone marrow Myeloid progenitor cells develop into cells

that respond early and nonspecifically to infection

Lymphoid progenitor cells develop into lymphocytes

Mononuclear WBC’s produced in bone marrow

Two major classes:B cells (mature in bone marrow, produce antibodies and part of antibody-mediated immunity.T cells(mature in Thymus, coordinate entire immune response and eliminate viruses hiding in infected cells, Attack and destroy, Responsible for cell mediated (cellular) immunity.

Substance, molecule, or agent (such as bacterium or virus) that triggers an immune response

Recognized by immune system as foreign

Produced to target a specific antigen When they combine with antigens, can

activate a cascade of proteins (complement)

Complement works with antibodies to destroy foreign invaders

Physical/mechanical barriers Innate immune system Adaptive (acquired) immune system

Skin-first line defense Flushing-tears, saliva, micturation, peristalsis Acid contents of stomach; bile salts Cilia action of lung and cough reflex Mucous membranes Inflammatory response and phagocytosis

(see the video of phagocyte engulfing Aspergillus & Candid conidia: http://en.wikipedia.org/wiki/file:s1-Polymorphonuclearcellswithconidiainliquidmedia.ogg.

Fever

1. Vascular phase2. Cellular phase3. Healing phase

Mechanical response Pathogenic organisms survive best at

normal body temperature Immune system can kill pathogens by

slightly raising body’s temperature Negative aspect

◦ Release of cytokines that produce harmful effects

Cellular barriers◦ Leukocytes involved◦ Do not confer long lasting immunity◦ Identify and eliminate pathogens

Complement Complex linear protein molecule Called an “effector” molecule

Leukocytes (WBC’s) Neutrophils Phagocytes Basophiles Eosinophils

Humoral Cell mediated Lymphocytes involved Two types

Macrophage attracted to/ingests foreign antigen

Antigenic proteins cleaved: fragments appear on surface of macrophage

T cell sees macrophage with antigenic protein on surface and stimulates B cell

Stimulated B cell divides and makes plasma cells; plasma cells make antibodies

Note: takes approx. 3 weeks after exposure for detectable antibodies to appear in the blood

IgM-current disease; first at site of initial exposure

IgG-first with subsequent exposure IgA-secreted on mucous membranes IgE-allergic reactions IgD-short-lived; cord blood

Note: A mnemonic to remember:◦ IgM=I’ve got it and I’m making it◦ IgG=I got it and it’s Gone

Genetic deficiencies Drugs Cancer Viral infections Malnutrition Stress Iatrogenic factors

The immune system is a complex network of cells, tissues and organs that work together to defend the body against attacks by “foreign” invaders

When the immune system hits the wrong target or is crippled, it can unleash a torrent of diseases, including allergy, arthritis and AIDS

EPI 201◦ Craig CG. Microbial Pathogenicity and Host

Response In: Chapter 14, APIC text of Infection Control and Epidemiology, 3rd ed.

◦ http://www.cancer.gov/cancertopics/understandingcancer/immunesystem (National Cancer Institute. The Immune System

◦ http://www.nlaid.nih.gov/topics/immunesystem/pages/default.aspx (National Institute of Allergy and Infectious diseases. The Immune System)