Fungal Serology and Immunodiffusion

Question 1

What are the four fungi often diagnosed though serology?

Answer 1

1. Histoplasma capsulatum
2. Blastomyces dermatididis
3. Coccidioides immitis
4. Aspergillus species

Question 2

All of the fungi

- growth in culture

Answer 2

slow growing if it grows at all

Question 3

Histoplasma capsulatum

- disease symptoms

Answer 3

Broad spectrum of disease from asymptomatic to mild respiratory symptoms to severe disseminated disease
- most severe in immunocompromised

Question 4

Histoplasma capsulatum

- geographic location found

Answer 4

Indiana and the Ohio River Valley

Question 5

Blastomyces dermatididis

- disease symptoms

Answer 5

Respiratory symptoms

Question 6

Blastomyces dermatididis

- geographic location found

Answer 6

Southeastern US (sometimes Indiana)

Question 7

Coccidioides immitis

- disease symptoms

Answer 7

Often severe disease - starting with respiratory symptoms and sometimes involving the central nervous system

Question 8

Coccidioides immitis

- geographical location found

Answer 8

Southwestern US

Question 9

Aspergillus species

- disease symptoms

Answer 9

respiratory symptoms

- most often problem in immunocompromised patients

Question 10

Aspergillus species

- geographical location found

Answer 10

Across the US

Question 11

What are 4 reasons to use serology/immunodiffusion for Antibody detection for the four fungi?

Answer 11

1. fungi are slow growing if they grow at all
2. most are biphasic (yeast and mold forms)
3. antibodies sometimes cross react
4. Immunodiffusion allow closely-related antibodies to be differentiated

Question 12

What is the simplest serologic reaction where a visible product is produced when antigen and antibody meet in optimal proportions and bind?

Answer 12

Precipitation

Question 13

In Precipitation both the antigen and antibody are ______ not cellular

Answer 13

soluble

Question 14

What is the difference in soluble precipitation antigens and soluble flocculation antigens?

Answer 14

Flocculation antigens are used in a milieu containing other substances.

Question 15

Precipitation in agar or gel is called _______?

Answer 15

Immunodiffusion

Question 16

Immunodiffusion:

- describe antigen

Answer 16

Antigen to the fungus being tested is placed in the center of the well (polyclonal)

Question 17

Immunodiffusion:

- describe antibody

Answer 17

Antibody to the fungus being tested serves as a positive control to the antigen and also as your unknowns

Question 18

Immunodiffusion:

- List reagents and equipment required in testing

Answer 18

Known antibody (pos control) and antigen and then patients’ unknown antibody

Question 19

Immunodiffusion:

- appearance of acceptable results for positive control sera

Answer 19

must have precipitate under the positive control to be valid

Question 20

Immunodiffusion:

• appearance of identity reaction
• pos or neg

Answer 20

• smooth curve (no spurs)

- pos

Question 21

Immunodiffusion:

• appearance of partial identity reaction
• pos or neg

Answer 21

• curve with single spur

- pos

Question 22

Immunodiffusion:

• appearance of non-identitiy reaction
• pos or neg

Answer 22

curve with two spurs

- neg

Question 23

Immunodiffusion:

• appearance of no reaction
• pos or neg

Answer 23

• no precipitate

- neg