6.36.3Defence Against Defence Against

Infectious Infectious DiseaseDisease

6.3.46.3.4 Outline how phagocytic Outline how phagocytic leucocytes ingest pathogens in the blood leucocytes ingest pathogens in the blood

and in body tissues.and in body tissues.• 1 type of WBCs—macrophages 1 type of WBCs—macrophages • Lg, change shape to engulf invaders Lg, change shape to engulf invaders

(phagocytosis) & squeeze in/out of (phagocytosis) & squeeze in/out of capillariescapillaries

• Recognizes Recognizes self/non-selfself/non-self• Proteins on cell surfaceProteins on cell surface• Self Self left alone left alone• Non-self Non-self phagocytosis, lysosomes phagocytosis, lysosomes

of macrophage digest itof macrophage digest it• ““NON-SPECIFIC” DEFENSE b/c NON-SPECIFIC” DEFENSE b/c

invader’s identity’s not known, just invader’s identity’s not known, just that it’s non-selfthat it’s non-self

6.3.5 Distinguish between antigens 6.3.5 Distinguish between antigens and antibodies.and antibodies.

• ABs-ABs-specificspecific proteins we produce, in proteins we produce, in response to a response to a specificspecific pathogen pathogen• Flu AB, measles AB, etc.Flu AB, measles AB, etc.• Y-shaped, Ag-binding sites at each Y-shaped, Ag-binding sites at each

tiptip• AB attaches to Ag’s sfcAB attaches to Ag’s sfc

• Cellular invaders (bacteria)Cellular invaders (bacteria)• Foreign Proteins @ outer sfc = Foreign Proteins @ outer sfc =

ANTIGENSANTIGENS (Ags) (Ags)• Usually have several diff Ag on sfc, so make Usually have several diff Ag on sfc, so make

several diff Abs against itseveral diff Abs against it

• Viral invaders tooViral invaders too

6.3.6 Explain antibody production.6.3.6 Explain antibody production.• B Cells (type of WBC)B Cells (type of WBC)• We all have lots diff B cells, each makes a We all have lots diff B cells, each makes a

diff ABdiff AB1.1. Specific AG identified (cold virus)Specific AG identified (cold virus)2.2. Specific B lymphocyte id’d that can produce Specific B lymphocyte id’d that can produce

AB to bind to AG (to proteins on virus coat)AB to bind to AG (to proteins on virus coat)3.3. B cell & many identical B cells clone selves B cell & many identical B cells clone selves

(mitosis) (mitosis) LOTS in a short period of time LOTS in a short period of time4.4. ““army” of B cells produce ABsarmy” of B cells produce ABs5.5. ABs released to bloodstream, find AGABs released to bloodstream, find AG6.6. ABs help eliminate the pathogen (various ABs help eliminate the pathogen (various

ways)ways)7.7. Some of cloned B cells remain in Some of cloned B cells remain in

bloodstream, give immunity from 2bloodstream, give immunity from 2ndnd infection by infection by samesame pathogen: MEMORY CELLS pathogen: MEMORY CELLS

6.3.76.3.7 Outline the effects of HIV on Outline the effects of HIV on imm sys.imm sys.

• Viruses work by finding a cell type in body that matches Viruses work by finding a cell type in body that matches its proteins (complementary)—why only some body cells its proteins (complementary)—why only some body cells affected by flu virus (nasal cells affected by flu virus (nasal cells nasal symptoms) nasal symptoms)

• HIV (virus) HIV (virus) AIDS (symptoms) AIDS (symptoms)• Infects Helper T cellsInfects Helper T cells• Latency period (infected cells remain Latency period (infected cells remain

alive) of several years before AIDSalive) of several years before AIDS• Helper T cells communicate which Helper T cells communicate which

cells need to clone & produce ABcells need to clone & produce AB• They die They die no more communication, no more communication,

AB not producedAB not produced• Can no longer fight off pathogens Can no longer fight off pathogens

(even mild ones), often die of 2-ary (even mild ones), often die of 2-ary infectionsinfections

6.3.86.3.8 Discuss the cause, transmission and social implications of Discuss the cause, transmission and social implications of AIDS.AIDS.

• Cause: HIV (6.3.7)Cause: HIV (6.3.7)• difficult to make vaccine b/c it hides latent for yrs difficult to make vaccine b/c it hides latent for yrs

& b/c it mutates quickly& b/c it mutates quickly• Medication-ethical reasons not researched much Medication-ethical reasons not researched much

in past (drug abuse, sexual activity leading to in past (drug abuse, sexual activity leading to HIV); recently, lots of $$ for researchHIV); recently, lots of $$ for research

• Transmission: Transmission: • person-person body fluids: sex, drugs, blood person-person body fluids: sex, drugs, blood

transfusions (not always tested in past!!)transfusions (not always tested in past!!)• Test: ELISA (HIV-AB test)Test: ELISA (HIV-AB test)

• Social Implications:Social Implications:• Once thought only homosexuals & drug abusers Once thought only homosexuals & drug abusers

(not so!—rapidly spreading, all at risk)(not so!—rapidly spreading, all at risk)• HIV+ discrimination: employment, insurance, HIV+ discrimination: employment, insurance,

education access, social acceptance, etc.education access, social acceptance, etc.• Not all countries have education/medical Not all countries have education/medical

treatment to deal w/diseasetreatment to deal w/disease• Inadequate medical care Inadequate medical care increase in infection increase in infection

ratesrates• Education is key, decrease risk of exposure: Education is key, decrease risk of exposure:

GLOBAL problem, needs a GLOBAL solution...not just GLOBAL problem, needs a GLOBAL solution...not just within the boundaries of our own country.within the boundaries of our own country.