THE HOST'S SPECIFIC (INDUCED) DEFENSES: HOW THE IMMUNE SYSTEM FIGHTS INFECTIOUS DISEASES

Reading Assignments: (1) Text: Chapter 7 (2) HANDOUTS: (A) DIAGRAM OF HOW THE IMMUNE SYSTEM FIGHTS INFECTIOUS DISEASES (B) Paul, W.E. Infectious diseases and the Immune System. Scientific American (September, 1993)

I. INTRODUCTION

A. Review Nomenclature for Lymphocytes – Effector and Memory Cells

B. Review Exogenous and Endogenous Processing of Antigens

C. Review Cell Surface Structures on B cells and T cells that Participate in Specific Immunity

II. HOW THE HOST'S SPECIFIC IMMUNE SYSTEM FIGHTS INFECTIOUS DISEASES

A. PRIMARY IMMUNE RESPONSE - be able to tell in a step by step fashion how the specific immune system uses:

1. Cellular immunity to kill virus infected cells

2. Cellular immunity to kill intracellular pathogens (i.e. delayed-type hypersensitivity)

3. Humoral immunity to fight extracellular pathogens (bacteria and viruses) and extracellular toxins.

(NOTE: The formation of memory cells is not shown on the handout. You should be able to put them into this diagram.)

B. SECONDARY IMMUNE RESPONSE

How does the secondary immune response come about? How does it differ from the primary response?

SELF STUDY ASSIGNMENT FOR LECTURE 9

VACCINES AND VACCINATION (IMMUNIZATION)

Reading Assignments: (1) Text: Chapter 44 (2) HANDOUT: Mims, C. N.J. Dimmock, A. Nash, and J. Stephen. 1995. Mims' Pathogenesis of Infectious Disease (4^th ed.) Academic Press, London.

(Note: You are not responsible for specific information about individual vaccines. These will be covered later in the course.)

Study questions:

1. What is a vaccine?

2. How do the primary and secondary immune response relate to vaccination?

3. What is active immunization vs passive immunization? What are the advantages and disadvantages of each approach to immunization? Differentiate between immune globulin and specific immune globulin.

4. What are the characteristics of an ideal vaccine? (See MIMS, p. 359)

5. List some important general principles that must be considered in order to produce an effective vaccine. (See MIMS pp. 359-364- # 1,2,3,4,6, 7,9)

6. What are the important differences, in principle, between killed and live vaccines?

7. Some viral vaccines contain live attenuated viruses. What attributes of a virus must be altered before it can be used as a live attenuated vaccine? How is attenuation accomplished? What major problem can arise with attenuated vaccines? What is the major guideline for using a live attentated vaccine in an immunocompromised host?

8. What is a toxoid vaccine?

9. When human infants are born, their immune system is not fully developed but they are passively protected against a variety of pathogens by the maternal IgG they have received in utero and if they are breast-fed, by secretory IgA. With these two kinds of passive protection in effect, why are very young infants vaccinated against some infectious diseases even before they can respond fully to foreign antigens?

10. List some complications and side effects of vaccines.

11. What is an adjuvant?

12. What is herd immunity?

13. Newer approaches to vaccination use a variety of alternative immunogens to whole microorganisms. Give three examples of such vaccines and briefly describe their modus operandi. Why in general are these vaccines considered to be advantageous?