Host Response to Infection

1. HOST RESPONSE TO
INFECTION
AIDA V.G.

2. UNIT OBJECTIVES:
• List components of immune system
• Describe types of immune response
• Enumerate normal flora of body
• Describe Immunization

3. Immunology

6. PROPERTIES OF IMMUNOGEN
Page 55

7. Properties
of immunogen
PAGE
55

8. Properties of immunogen
1. FOREIGNESS
:genetically
foreign to the
host
: recognized
as non-self
2. CHEMICAL
COMPOSITION
: protein -
-most immunogenic,
-most antigenic
:pure lipid & nucleic
acid - poor
immunogens

9. 3. CHEMICAL
COMPLEXITY
• : the more structurally
complex – the more
immunogenic
4. GENETIC
CONSTITUTION OF
HOST
:Pure polysaccharides
– large amount
needed
:synthethic polymers
– not immunogenic

10. Properties of immunogen
5. MOLECULAR SIZE
: > 100,000 Dalton - very potent
immunogens
: <10,000 daltons –weak immunogen
6. DOSE / METHOD OF ADMINISTRATION-
: Subcutaneous – more immunogenic
than intravenous & intragastric

12. First line & second line of defense
• Also called as:
INNATE IMMUNITY, Natural Immunity
• Since birth. Exists prior to exposure to the
antigen
• Non-specific
• 2 functions: kill m.o. & activate acquired
immune response
• No memory. Does not improve after
antigen exposure Page
57

13. First Line of defense
• AIM: prevent *e_t_y of m.o. Into the body
• MAJOR LINE OF DEFENSE: Intact skin &
mucous membrane
• MECHANICAL / CHEM. BARRIER –
Keratin layer of skin

14. LINE OF DEFENSE /
other name: DEFENSE MECHANISM

15. Page 57
& etc.

16. First Line of defense: factors that limit
entry

17. Second Line of defense
Aim : Destroy m.o.
: Limit their growth

19. Lines of defense:
SECOND LINE OF DEFENSE
PAGE
58

20. Lines of defense;
SECOND LINE OF DEFENSE
INTERFERONS
Inhibits Viral
replication

21. Lines of defense;
SECOND LINE OF DEFENSE
NEUTROPHILS/
*Monocytes
Phagocytosis -
Ingest & destroy
microbes

22. Lines of defense;
SECOND LINE OF DEFENSE
FEVER
Retards
bacterial
growth

24. THIRD Line of defense
• B cells & T cells

26. I. PRIMARY LYMPHOID ORGANS
> Production & maturation of B cells & T
cells
Page 56

27. II. SECONDARY LYMPHOID ORGANS
B cells & T cells encounter antigens through
their receptors and trapped
Page 56

30. T lymphocytes (T CELLS)

31. w/ memory
T Helper cells
• Antigen recognition,
• Promote inflammation &
antibody production
• Regulates production of
cytotoxic T cells
Cytotoxic T cells
• Recognize & kill virus-
infected cells, tumor cells
& foreign cells (e.g.
Tissue graft)
• w/ memory

33. B lymphocytes (B CELLS)

34. ANTIBODY

35. Page
59

36. IgM

37. IgD

38. IgA

39. IgE

40. IgG

42. • ACTIVE IMMUNITY
– Resistance induced after contact w/ Ag
– Slow onset
– Long term resistance
• PASSIVE IMMUNITY
– Resistance is based on antibody preformed in
another host
– Short lifespan

43. . Ex. Gamma
globulin injection
Ex. ATS
Ex. Anti-Rabies
Injection
Ex. Vaccine
Ex. TT
Ex. Maternal
IgG in
newborn,
Ex. in mother’s
milk
Ex. Acquired
Disease
- Got sick