In this video, we demonstrate a cytotoxicity assay to assess Cryptococcus neoformans, a pathogenic fungus, infection in macrophages. The cytotoxicity is determined by the release of cytoplasmic lactate dehydrogenase enzyme due to macrophage lysis caused by Cryptococcus neoformans infection.
Protocol
1. Verification of infection NOTE: Using a cytotoxicity assay, infection proficiency can be measured. The following protocol will highlight the application of a cytotoxicity product to measure LDH (lactate dehydrogenase) release. Other cytotoxicity products can also be used Preparation of C. neoformans infection of macrophage cells Preparation of fungal cells Using a glycerol stock, streak wildtype C. neoforma…
Divulgaciones
The authors have nothing to disclose.
Materials
100 mM Tris-HCl, pH 8.5
Fisher Scientific
BP152-1
Maintain at 4°C
60 x 15 mm Dish, Nunclon Delta
ThermoFisher Scientific
174888
6-well cell culture plate
ThermoFisher Scientific
140675
Conical falcon tubes (15 mL)
Fisher Scientific
05-539-12
Countess II Automated Cell Counter
ThermoFisher Scientific
AMQAX1000
Not essential, haemocytometer can be used as an alternative.
CytoTox 96 Non-Radioactive Cytotoxicity Assay
Promega
G1780
DMEM, high glucose, GlutaMAX Supplement
ThermoFisher Scientific
10566016
Fetal Bovine Serum (FBS)
ThermoFisher Scientific
12483020
Heat inactivate by incubating at 60°C for 30 minutes. Prepare 50 ml aliquots and flash freeze. Thaw prior to media preparation
Hemocytometer
VWR
15170-208
HEPES
Sigma Aldrich
H3375
Prepare 40 mM HEPES/8 M Urea in bulk stock solution, flash frozen, store at -20°C until use. Discard after each use (do not freeze-thaw repeatedly).
L-glutamine
ThermoFisher Scientific
25030081
Can be aliquot and frozen for storage. Thaw prior to media preparation.
Microcentrifuge
Eppendorf
13864457
Penicillin : Streptomycin 10k/10k
VWR
CA12001-692
Can be aliquot and frozen for storage. Thaw prior to media preparation.
Phosphate-Buffered Saline
VWR
CA12001-676
Purchase not required. PBS can also be prepared but sterile filteration must be performed before use.
Pipette, Disposable Serological (10 mL)
Fisher Scientific
13-678-11E
Pipette, Disposable Serological (25 mL) Basix
Fisher Scientific
14955235
Trypsin/Lys-C protease mix, MS grade
Pierce
A40007
Maintain at -20 °C.
Urea
Sigma Aldrich
U1250-1KG
Prepare 40 mM HEPES/8 M Urea in bulk stock solution, flash frozen, store at -20 °C until use. Discard after each use (do not freeze-thaw repeatedly).
A Lactate Dehydrogenase Release Assay to Detect Cryptococcus neoformans Infection in Macrophages. J. Vis. Exp. (Pending Publication), e21660, doi: (2023).