Question

(5) Fill in the blanks in the following statements. a. Variation in influenza surface proteins is generated by and b. Variation in pilin, which is expressed by many gram-negative bacteria, is generated by the process of c. The diphtheria vaccine is a formaldehyde- treated preparation of the exotoxin, called a d. A major contribution to nonspecific host defense against viruses is provided by and e. The primary host defense against viral and bacterial attachment to epithelial surfaces is (6) Describe the nonspecific defenses that operate when a disease-producing microorganism first enters the body

Subject Immunology

Answer 1

a- Since Influenza virus is a RNA virus it has more chances of mutation in genome which results in surface protein variations and the process is defined as Genetic Drift and Genetic Shift.

b- Variation in pilin, which is expressed by many Gram-negative bacteria is a process of antigenic variance and generated through a process of Antigenic Switching. This process happens through recombination between different cassettes of avaialbel genes of same protein.

c- Diphtheria toxin is an exotoxin secreted by Corynebacterium diphtheriae, the pathogenic bacterium that causes diphtheria and known as A-B toxin.

d-  A major contribution to nonspecific host defence against viruses is provided by Anatomical barriers and Interferons.

e- The primary host defence against viral and bacterial attachment to epithelial surfaces is cell mediated immune response /or chemical barriers.