Exam 3 – Immunology I

What is innate immunity?

• aka genetic immunity, aka nonspecific

  • encompasses innate defenses covered last time

• species immunity – all members of species “born with” (part of innate immunity)

  • ex. humans do not get infected with canine distemper

What are the two parts of the adaptive (specific) section of the immune system?

• cellular components – cell mediated

• humoral components – antibodies

What is an antigen?

• something the body recognizes as foreign and mounts an immune response to 

  • usually a protein

    • sometimes polysaccharides (sugar)

  • often on surface of microoganisms and cells

What is an epitope?

area on antigen where antibodies bind

What is an antibody?

a protein produced in response to an antigen

What is acquired immunity

• immunity obtained in some other way than heredity

• naturally or artificially acquired

• active or passive 

  • active – production of antibodies (you make them)

    • can be natural or artificial

  • passive – ready-made antibodies introduced (pre-formed antibodies from somewhere else are put into someone)

    • can be natural or artificial 

• SPECIFIC

• ANYTIME ANTIBODIES INVOLVED

Name all the various types of immunity

What are the four types of acquired immunity?

• naturally acquired active immunity (sickness)

• artificially acquired active immunity (vaccine)

• naturally acquired passive immunity (fetus from mother in womb)

• artificially acquired passive immunity (someone else’s antibodies given in a serum like a drug)

Overview of whole immune system?

What are the cells and tissues of the immune system?

• Lymphocytes – WBCs that carry out immune responses

  • B cells – make specific antibodies

    • humoral immunity – antibodies in the blood

  • T cells 

    • T c are cytotoxic (cell killers – recognize our own cells that are infected and kills them – very specific)

    • T h are “helpers” to specific responses

      • help cell mediated immunity

      • help humoral immunity

B cells

• antibody production

  • bone marrow and bursa (of poultry?)

• humoral immunity

T cells

• cell mediated immunity (thymus)

• also involved in humoral response

What is a lymph and a lymph node

• lymph – like blood but no RBCs

• lymph nodes – high concentration of WBCs

  • interactions with microbes and antigens

What are lymphatic organs?

• lymph nodes – filter foreign materials out of lymph

• thymus – maturation of T-cells (lymphocytes)

• spleen – largest lymphatic organ and contains phagocytes

• tonsils – aggregation of lymphocytes

• for all

  • swelling is a sign of infection

  • all involved in immunity

  • cite of fighting between our immune system and antigens

What are the properties of adaptive immunity?

• specificity

• memory

• self versus non-self recognition

  • tolerance

What is clonal selection theory?

• explains specificity and memory

• the immune system can recognize billions of antigens

• each T cell and B cell is specific for one antigen

• the immune system has “memory”

• similar for T cells and B cells 

• each T and B cell only recognizes one antigen, but it needs times to build response to antigen it recognizes

• memory cells are available after first infection to fight second infection

What is the clonal deletion theory?

• it explains tolerance

• during development, T and B cells that recognize “self” antigens are deleted

• this results in tolerance for “self”

What is the antigen presenting cell (APC)?

• usually macrophages

• ingest pathogen

• lyse pathogen

• process antigens 

What is antigen presentation?

• antigens are presented on the surface of the APC using major histocompatibility complex (MHC) proteins

• T cell receptors (TCR) recognize specific antigens and MHC

• T helper (T h) cell is activated

  • simulated cell mediated and/or humoral response

What is humoral (liquid) immunity?

• antibodies (made by B cells) in the blood and fluids

  • effective before invaders enter cells

  • small pathogens destroyed

What is cell-mediated immunity?

• carried out by T cells

  • antigens embedded or within cells

  • entire cell is destroyed

What happens during humoral immunity (AKA antibody mediated immunity)?

• B cells express antibodies on their surface

• Bind specific antigen then divide

• some offspring are plasma cells that pump out antibody

• some offspring are memory cells

What are antibodies?

• immunoglobulins (Ig)

• soluble proteins

• found in serum (plasma) and some other body fluids (milk, gastric secretions, mucus)

• antiserum

• 5 classes

What are the five classes of Ig?

• IgG (~80% of total, 2º [2nd] response)

• IgM (largest, 1º [1st] response)

• IgA (secretions)

• IgD

• IgE (allergies)

What is primary response?

• when a B cell first finds its antigen with the help of T helper cell

  • produce plasma cells and IgM antibodies (big, multipurpose [?], less potent)

What is secondary response?

• memory cells quickly respond to antigen without the help of T helper cell

  • produce plasma cells and IgG antibodies (very potent)

What do the primary and secondary responses look like when graphed?