IMMUNITY

IMMUNITY – body’s reaction to any foreign body that might enter our tissues

2 types:

• NON SPECIFIC/ CELLULAR / Innate immunity present in our body since we were born
• SPECIFIC

Mediators (non specific)

1. MECHANICAL BARRIERS

• Skin (keratinized)
• Body secretions ( sweat, oil)
• Cilia (transports)
• Mucus (traps organism entering the Respiratory tract)

2. CHEMICAL BARRIERS

• Enzymes (lysozymes)
• Acids ( kills bacteria by denaturation)
  Fatty acids – skin
  Gastric acids – stomach
• Complement system – becomes activated in cascade fashion 1,2,3…..
  Activated Complements System – presents antigen to the bacteria; once activated, has to be removed from the body

3. INFLAMMATORY RESPONSE

Presents the 5 Cardinal signs which is chemically mediated that can come from:

• Damaged tissues
• Inflammatory cells
• Even from the bacteria itself

5 Cardinal signs & symptoms of inflammation:
1. redness (rubor)
2. swelling (tumor)
3. pain (dolor)
4. heat (calor)
5. loss of function (functiolaesa)

FXN:

• forms a barrier to confine infection
• tries to eliminate infectious agent
• initiates repair of damaged tissues

4. CELLS – WBC’s

a) GRANULOCYTES – granulocytic leukocytes; WBC’s with granules inside the cytoplasm

1. Neutrophiles – plenty; 1st line of defense; 1st to respond during an infection
HALLMARK OF ACUTE INFECTION (10days)
Once they leave, they cannot go back (through “DIAPEDESIS”)
CBC - increased Neutrophiles = acute infection
Disease is current; can be bacterial

HOW DO NEUTROPHILES KILL BACTERIA?

• Phagocytic – active engulfing
• Degranulation – release granules in the cytoplasm which contains cytotoxins that kill the bacteria

2. Eosinophiles – mediate for Allergies; Hypersensitivity reaction; Anaphylactic reaction;

Contains vasoactive dilators:

• Serotonin
• Histamine
• Bradykinin

Limited phagocytic activities
“Picky eaters” eat only * complement system, * Ag aggregated with Ab

3. Basophiles – HEPARIN – anti coagulant; lesser blood clots

b) AGRANULOCYTES

1. Monocytes – found in the blood which rids bacteria, virus, and other debris
“scavengers” (10 days in circulation)
ACTIVE phagocytes
DIAPEDESIS – mode of escape w/o damage
MACROPHAGES – once they are out, monocytes take this form; derivative
Neutrophiles, Monocytes, Macrophages = 3 active phagocytic cells

2. Lymphocytes – non phagocytic cells
HALLMARK OF CHRONIC INFECTION

a) T –CELLS/ T-LYMPHOCYTES = (Cellular Immunity)
T- cells mature in the Thymus glands(Lymphoid organs)
Once there is an infection, they become ACTIVE EFFECTOR CELLS

• Natural killer cells – non phagocytic cells which kills by secreting LYMPHOKINES
  kills ON CONTACT; has intimate contact with bacteria (sila ang Police na pumapatay sa kahit sinong magnanakaw - virus,bacteria)
• Helper cells – calls for other WBC’s which circulate around the body by secreting “OPSONINS” (chemically attract WBC). WBC aids in the attack; (nagtatawag para may katulong ang Police sa laban)
• Suppressor cells – the absence of these mediators will cause destruction of normal tissues
  (taga awat kung bugbog na ang kalaban, kung walang aawat sila-sila din ang magpapatayan kahit kakampi nila- "Autoimmune disease")
  

b) B CELLS/ B LYMPHOCYTES - mediator of specific immunity

• must 1st recognize specific Ag (nag draw-drawing ng cartographic sketch ng magnanakaw the 1st time na pumasok sya sa bahay)
• acquires Ab’s once exposed to microorganism (ipapakita niya yung drawing niya sa police para next time na papasok ang magnanakaw kilala na ng police at bubugbugin na niya ang magnanakaw)

improves with exposure (mas madalas niya makita at mas madalas sya manakawan, mas lalo na niya nakikilala ang magnanakaw para lalong maituro at mahuli ng police )

Humoral immunity

ACTIVE EFFECTOR B CELLS:

• MEMORY CELLS – (Ang "WITNESS" na nag draw-drawing ng cartographic sketch ng magnanakaw the 1st time na pumasok sya sa bahay)
• PLASMA CELLS – makes Ab’s specific to description of the memory cells; (bumubuo ng "TASK FORCE POLICE" para lumaban sa muling pagbalik, dun lang sa magnanakaw na nai-drawing ng witness - "Antigen-Antibody Response")
  
  
  IMMUNIZATION – is the process by which we reinforce our immune system by introducing antigens that stimulate antibody responses
• ACTIVE – our own body participates in the production of Ab’s
  slow acting so it is introduced during our childhood; last longer than passive
  VACCINES – made up of dead, inactivated organisms; parts of Ag’s; or attenuated (weakened virus or bacteria)
• PASSIVE – giving antibodies (Ab’s) especially during epidemic
  Gives immediate protection but temporary (3-6months)
  Ex. Equine vaccine from horses
  A) NATURAL – from mother to baby
  B) PASSIVE – Ab’s from other sources