Humoral Response 2

Question 1

Neutralization: Fab

Answer 1

• virus binds to cell surface
• receptor mediated endocytosis of virus
• acidification of endoscope after endocytosis triggers fusion of virus with cell and entry of viral DNA
• antibody blocks binding to virus receptor and can also block fusion event

Question 2

Opsonization: Fab and Fc

Answer 2

Antibody opsonization is a process by which a pathogen is marked for destruction by:
▪ antibody-dependent cellular phagocytosis (ADCP)
▪ antibody-dependent cellular cytotoxicity (ADCC)

Question 3

What is the function of FcyRI

Answer 3

Phagocytosis and activation of phagocytes

Found on macrophages ,neutrophils ,eosinophils

Question 4

ADCP: Fab/Fc

Answer 4

Antibodies of certain IgG subclasses bind to microbes and are recognized by Fc receptors on phagocytes
-signals promote phagocytosis

Question 5

ADCC (NK cells): Fab/Fc

Answer 5

Antibodies of IgG1 and IgG3 binds to cells and their Fc regions are recognized by an Fcy receptor on NK cells
The NK cells are activated and kill the antibody -coated cells

Question 6

ADCC (eosinophils): Fab/Fc on IgE

Answer 6

• FceRI
• IgE antibody binds to helminths and recruits and activates eosinophils via FceRI leading to degranulation of the cells and release toxic mediators
• IL5 secreted

Question 7

Transported across the epithelium

Answer 7

IgA

Question 8

Transported across the placenta

Answer 8

IgG1

Question 9

▪ Antibodies also serve protective functions in 2 special sites

Answer 9

• mucosal organs

* Fetus/neonate gut

Question 10

Mucosal immunity

Answer 10

Immunoglobulin A is produced in mucosal lymphoid tissues
▪ Transported across epithelia
▪ Neutralizes microbes in lumen of mucosal organs

Question 11

Neonatal Immunity

Answer 11

Passive immunity from the mother
▪ Acquire IgG by two routes that rely on neonatal Fc receptor (FcRn):
• Placenta while in uterus
• Gut after ingestion of mother’s colostrum

Question 12

Mechanism of immune evasion

Answer 12

• antigenic variation
• inhibition of complement activation
• blocking by hyaluronic acid capsule

Question 13

Is there memory with passive immunity

Answer 13

No

Question 14

Whole vaccines

Answer 14

• Killed whole bacterial cells or inactivated virus • Live, attenuated bacterial cells or virus

Question 15

Acellular or subunit vaccine

Answer 15

Antigens derived from bacterial cells or virus particles

• Typically, surface molecules or neutralized toxins (toxoid)

Question 16

Recombinant vaccine

Answer 16

Genetically engineered

• Selected genes for microbial antigens are cloned into a vector

Question 17

Whole vaccines: killed or inactivated

Answer 17

• Stimulate a weaker immune response: Humoral only

- boosters

Question 18

Live attenuated vaccines:

Answer 18

Stimulate a strong immune response: Humoral + CMI • Require fewer doses and booster shots
• Require refrigeration, more difficult to transport
• Possibility of reversion (back mutation to wild type)

Question 19

Toxoid vaccines

Answer 19

acellular): formalin treated bacterial toxins

• Diphtheria, Tetanus, and acellular pertussis (DTaP)

Question 20

Conjugate vaccines

Answer 20

encapsulated bacteria (incapable of
activating CMI)
• Capsular polysaccharide molecule conjugated to protein (usually a toxoid)
✓Ensures CMI with class switching
• HaemophilusinfluenzatypeB(Hib)
• Streptococcuspneumonia,pneumococcalconjugate(PCV13)
✓13 capsular serotypes
✓Indicated for use in infants
• Neisseriameningitidis

Question 21

Subunit vaccines:

Answer 21

viral components • Hepatitis B surface antigen
• HPV
✓9-valent vaccine (released 2015)

Question 22

Recombinant vector vaccines

Answer 22

-Selected genes for microbial antigens are cloned into a vector
• Vaccinia virus, Canarypox virus, attenuated polio virus, adenovirus
• Attenuated Salmonella, Mycobacterium bovis (BCG)
• The cloning host will produce the antigen for use in a vaccine

Question 23

DNA/RNA vaccines

Answer 23

DNA plasmids encoding antigenic
proteins injected into patient
• Expression of foreign proteins in host cells
• Strong humoral and cell-mediated response

Question 24

When can you give fetus and neonates live attenuated vaccines

Answer 24

After 12 months

Question 25

What immunoglobulin is used to diagnose infections in neonates

Answer 25

IgM n

Question 26

Infants have _______ of adult _____ at age 12 months so _______ is important

Answer 26

20%
IgA
Colostrum