Types of immunity

1. Types Of Immunity
Dr. Sara Sadiq

2. What is immunity?
• Immunity is the body's ability to fight off
harmful micro-organisms –PATHOGENS-
that invade it.
• The immune system produces antibodies
or cells that can deactivate pathogens.
• Fungi, protozoans, bacteria, and viruses
are all potential pathogens.

3. Characteristics of Immunity
• Recognition of self versus non-self
• Response is specific
• Retains a “memory” allowing an
accelerated second response
• Can respond to many different
materials
• Involves lymphocytes and
antibodies

5. Fig 21.1

6. Innate (Non-Specific) Immunity
Innate Immunity Made Up Of 4 Forms
• Anatomical
• Physiological
• Phagocytic
• Inflammatory

7. Anatomical Barriers:
• Skin
• physical barrier to microbes
• Keratin resistant to most bacterial enzymes & toxins
• secretions are acidic pH 3-5
• Mucosa
• physical barrier & produces a variety of protective chemicals
• Gastric mucosa
• very acidic & produces proteolytic enzymes
• Saliva & lacrimal fluid contain lysozyme
• Mucous
• traps bacteria & moves them away from epithelial surface

8. • pH (stomach)
• Temperature (fever)
• Soluble Factors (interferons, lysozymes)
Physiologic Barriers

9. Phagocytic Barriers
• Macrophages: derived from monocytes
• Kupffer cells (liver) & microglia (brain)
• Ingest cellular debris, foreign material, bacteria, fungi
• Neutrophils: ingest pathogens
• Eosinophils: weakly phagocytic of pathogens. Attack parasites
(degranulation)
• Mast Cells: phagocytic of various bacteria

10. 2. Adaptive / Acquired (Specific) Immunity
• Two Components of Adaptive Immune System
• Humoral (humoral mediated immunity)
• B-Cells  Plasma Cells  Antibodies
• Cellular (cellular mediated immunity)
• CD8+ T-Cells  Direct Cellular Killing
• CD4+ T-Cells  Recruitment of other immune cells (inflammatory response)

11. • 4 Characteristics
• Memory
• Diversity
• Antigenic Specificity
• Self/ nonself recognition
Adaptive/ Acquired (Specific) Immunity

12. Types of Acquired Immunity
• Active Immunity
- Naturally-Acquired Active Immunity
- Artificially-Acquired Active Immunity
• Passive Immunity
- Naturally-Acquired Passive Immunity
- Artificially-Acquired Passive Immunity

13. • The production of antibodies against a specific
disease by the immune system.
• Naturally acquired through disease
• Artificially acquired through vaccination
• Vaccines include inactivated toxins, killed
microbes and viable but weakened
microbes.
• Active immunity is usually permanent
Active Immunity

14. 1. Cell-Mediated Immunity
Involves specialized set of lymphocytes called T cells that recognize
foreign antigens on the surface of cells, organisms, or tissues:
Helper T cells
Cytotoxic T cells
T cells regulate proliferation and activity of other cells of the immune
system: B cells, macrophages, neutrophils, etc.
Defense against:
Bacteria and viruses, Fungi, protozoa, and helminths
Cancer cells
Transplanted tissue
Naturally Acquired Active Immunity

15. Acquired Active Immunity
2. Humoral Immunity
• Involves antibodies (secreted from B cells) dissolved in the
blood plasma.
• Demonstrated as a immune response using only the blood
serum.
• Defense against bacteria, bacterial toxins, & viruses.
• Naturally acquired: natural exposure to antigen (i.e.
infection)
• Artificially acquired: vaccines

16. • Protection against disease through antibodies produced by
another human being or animal.
• Effective, but temporary
• Natural: Maternal antibody crosses the placental barrier conferring
temporary immunity to the baby
• Artificial: Antibodies harvested from an outside source given by
injection protect from immediate threat but no memory is formed
(antitoxins, antivenins , gamma globulin, etc.)
Passive Immunity

20. Thank
You