Immunology Exam 1

Question 1

GAS Extracellular Virulence Factors

Answer 1

• SLO and SLS
• Hyaluronidase
• DNAses A, B, C, D
• Streptokinase
• Erythrogenic Toxins

Question 2

Streptokinase

Answer 2

Helps to dissolve clots

Question 3

Hyaluronidase

Answer 3

Breaks down extracellular matrix (ECM)

Question 4

Erythrogenic toxins

Answer 4

Associated with scarlet fever strains
- 2nd day rash on trunk and face
- “Strawberry” tongue
- Sloughing of skin in second week

Question 5

Impetigo

Answer 5

• Common symptom of GAS (children)
• Extremely contagious
• Honey-colored crusts

Question 6

Necrotizing fasciitis

Answer 6

• Rare complication of GAS
• Secondary to wound infection, organism rapidly progresses through muscle
  Treatment:
  1. Debridement
  2. Intramuscular Antibiotics
  3. Amputation

Question 7

GAS Sequelae Causes

Answer 7

Rheumatic Fever - ASO
Acute Glomerulonephritis - Anti-DNAse B

Question 8

ASO Reference Method

Answer 8

• Neutralization Reaction
• Todd Units (1 / titer of last tube w/o hemolysis)
  Significant titers: >200 TU (adult), >300 TU (child), up 50 TU in 2 weeks

Question 9

Infectious Mononucleosis

Answer 9

• EBV (herpes virus)
• Infects B lymphocytes
• Lymphoproliferative disorder (60-90% of WBC are lymphs, 5-30% are reactive)

Question 10

Forssman (Heterophile Antibody)

Answer 10

Guinea Pig Kidney - Reacts
Bovine RBCs - NR
Sheep RBCs - Reacts

Question 11

Mono (Heterophile Antibody)

Answer 11

Guinea Pig Kidney - NR
Bovine RBCs - Reacts
Sheep RBCs - Reacts

Question 12

Serum Sickness (Heterophile Antibody)

Answer 12

Guinea Pig Kidney - Reacts
Bovine RBCs - Reacts
Sheep RBCs - Reacts

Question 13

Anti-VCA (IgM)

Answer 13

“Viral Capsid Antigen”, first antibody to appear

Question 14

Anti-VCA (IgG)

Answer 14

Appears early and a higher levels, may be present life long

Question 15

Anti-EA-D

Answer 15

Associated with acute infection of EBV

Question 16

Anti-EA-R

Answer 16

Associated with acute infection of EBV. Found in young adults but not children.

Question 17

Anti-EBNA

Answer 17

“Epstein Barr Nuclear Antigen”. Appears after acute infection and increases in convalescence.

Question 18

Febrile Agglutinins

Answer 18

Antibodies to microorganisms associated with persistent fever
- Cause RBCs to agglutinate (cold agglutinins)

Question 19

Widal Test

Answer 19

Agglutination test to detect antigens of various Salmonella species.
- Can differentiate between species
- O = Somatic Antigen (< 6 months) (1:160+ indicative)
- H = Flagellar Antigen (1 year +) (1:80)
- Vi = Capsular Antigen, highly virulent S. typhi and S. paratyphi (Never leaves Carriers), Can cause false negative O, boil to correct

Question 20

Tularemia

Answer 20

• Francisella tularensis
• Small mammals and birds
• Acquired through contact with animals
• Cross react with Brucella antibodies
• High titers in primary disease (1:160+)

Question 21

Brucellosis

Answer 21

• Brucella abortus
• Normal flora in genital and urinary tract of cows, pigs, and buffalo
• Acquired through eating meat or occupational exposure
• (1:80 significant, 1:160 indicative)

Question 22

Rickettsial Disease

Answer 22

• Recurrent Fever
• Acquired through tick, mite, and lice bites
• GNC

Question 23

Weil Felix Reactions

Answer 23

Detect Reckettsia Disease by cross reactivity with Proteus Antigens

Question 24

RMSF (Rocky Mountain Spotted Fever)
Epidemic Typhus
Murine Typhus

Answer 24

OX19 ++++ (1:160-1:320)
OX2 +
OXK neg

Question 25

Scrub Typhus

Answer 25

OX19 neg OX2 neg OXK ++++

Question 26

Other tickborne SFG (Spotted Fever Group) Infections

Answer 26

OX19 + OX2 ++++ OXK neg

Question 27

Hydatidiform Mole

Answer 27

- Chorionic villi enlarge into grapelike clusters - Can be complete moles (no fetal tissue) or partial moles - More common in older women

Question 28

Choriocarcinoma

Answer 28

- Malignancy of fetal origin - May disseminate, usually to lungs

Question 29

Testicular Teratoma

Answer 29

- Embryonic germ cell tumor - Composed of different kinds of tissues (skin, hair, muscle) - Produce HCG in men

Question 30

BHCG

Answer 30

Lateral Flow Sandwich Immunoassay - Highest near end of 1st Trimester - Fall to 10-15% of peak in 2nd and 3rd Trimester

Question 31

TORCH Test

Answer 31

TOxoplasmosis Rubella Cytomegalovirus Herpes

Question 32

Oocysts

Answer 32

Toxoplasmosis. Spore-like stage that is ingested by humans

Question 33

Tachyzoites

Answer 33

Toxoplasmosis. Mobile form that invades neural tissue

Question 34

Bradyzoites

Answer 34

Toxoplasmosis. Tissue cyst forming units that can lay dormant indefinitely

Question 35

Toxoplasmosis Treatment

Answer 35

- Pyrimethamine and sulfadiazine - Treat baby for first two weeks after birth

Question 36

Rubella Characteristics

Answer 36

- ssRNA virus of the togavirus family - Benign, self-limiting with mild upper respiratory tract infection, erythema (rash)

Question 37

Rubella Immune Titer (IgG)

Answer 37

1:8 or 1:10

Question 38

CMV (Cytomegalovirus)

Answer 38

- Belongs to herpes family - Associated with WBCs - Greatest risk: HIV+, Transplant patients, Premees - "Owl Eye" inclusions in infection

Question 39

Herpes

Answer 39

- Herpes simplex virus - Type 1: upper body, oral cavity (most infections) - Type 2: genital lesions - Latent infection in lymphoid and CNS ganglia cells

Question 40

Herpes Treatment

Answer 40

- Acyclovir or vidarabine

Question 41

Direct Agglutination

Answer 41

Antigen is a natural particle (often an RBC)

Question 42

Indirect (Passive) Agglutination

Answer 42

AntiGEN is adsorbed onto surface of an artificial particle (latex beads, etc)

Question 43

Reverse Indirect Agglutination

Answer 43

AntiBODY is adsorbed onto surface of an artificial particle (latex beads, etc)

Question 44

Agglutination Inhibition

Answer 44

Competitive between particle and the and its antigen for limited antibody - If agglutination, neg - If no agglutination, pos

Question 45

Capture (sandwich) immunoassays

Answer 45

Antibody-antigen-antibody

Question 46

Double Antibody immunoassays

Answer 46

Antigen-antibody-antibody

Question 47

Direct Immunofluorescence

Answer 47

Patient antigen adsorbed to slide, tagged antibody bound

Question 48

Indirect Immunofluorescence

Answer 48

Antigen adsorbed to slide, patient antibody bound, tagged antibody bound (like double-antibody immunoassay)